No-show keyframes

Abstract

Decoding using no-show keyframes includes obtaining encoded no-show keyframe data from an encoded bitstream, wherein the encoded no-show keyframe data includes data indicating that the encoded no-show keyframe data is for a keyframe and data indicating that the encoded no-show keyframe data is for a no-show frame. Decoding using no-show keyframes includes obtaining reconstructed no-show keyframe data by decoding the encoded no-show keyframe data using intra prediction, subsequent to obtaining the encoded no-show keyframe data, obtaining encoded overlay frame data from the encoded bitstream, subsequent to obtaining the reconstructed no-show keyframe data, obtaining reconstructed overlay frame data by decoding the encoded overlay frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data, including the reconstructed overlay frame data in output data for display, excluding the reconstructed no-show keyframe data from the output data, and outputting the output data.

Description

Atty. Doc. No. GOGL-2131-A-WO PATENTNO-SHOW KEYFRAMESBACKGROUND

[0001] Digital images and video can be used, for example, on the internet, for remote business meetings via video conferencing, high-definition video entertainment, video advertisements, or sharing of user-generated content. Due to the large amount of data involved in transferring and processing image and video data, high-performance compression may be advantageous for transmission and storage. Accordingly, it would be advantageous to provide high-resolution image and video transmitted over communications channels having limited bandwidth.SUMMARY

[0002] This application relates to encoding and decoding of image data, video stream data, or both for transmission, storage, or both. Disclosed herein are aspects of systems, methods, and apparatuses for encoding and decoding using no-show keyframes.

[0003] Variations in these and other aspects will be described in additional detail hereafter.

[0004] An aspect is a method for decoding using no-show keyframes. Decoding using no-show keyframes may include obtaining encoded no-show keyframe data from an encoded bitstream, wherein the encoded no-show keyframe data includes data indicating that the encoded no-show keyframe data is for a keyframe and data indicating that the encoded no-show keyframe data is for a no-show frame. Decoding using no-show keyframes may include obtaining reconstructed no-show keyframe data by decoding the encoded no-show keyframe data using intra prediction, subsequent to obtaining the encoded no-show keyframe data, obtaining encoded overlay frame data from the encoded bitstream, subsequent to obtaining the reconstructed no-show keyframe data, obtaining reconstructed overlay frame data by decoding the encoded overlay frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data, including the reconstructed overlay frame data in output data for display, excluding the reconstructed no-show keyframe data from the output data, and outputting the output data.

[0005] An aspect is an apparatus for decoding using no-show keyframes. The apparatus includes a non-transitory computer readable medium, and a processor configured to executeinstructions stored on the non-transitory computer readable medium to obtain encoded no-show keyframe data from an encoded bitstream, wherein the encoded no-show keyframe data includes data indicating that the encoded no-show keyframe data is for a keyframe and data indicating that the encoded no-show keyframe data is for a no-show frame. The processor may be configured to execute instructions stored on the non-transitory computer readable medium to obtain reconstructed no-show keyframe data wherein, to obtain the reconstructed no-show keyframe data, the processor executes the instructions to decode the encoded no-show keyframe data using intra prediction, obtain, subsequent to the encoded no-show keyframe data, encoded overlay frame data from the encoded bitstream, obtain reconstructed overlay frame data wherein, to obtain the reconstructed overlay frame data, the processor executes the instructions to decode the encoded overlay frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data, include the reconstructed overlay frame data in output data for display, exclude the reconstructed no-show keyframe data from the output data, and output the output data.

[0006] An aspect is a non-transitory computer-readable storage medium having stored thereon an encoded bitstream. The encoded bitstream may include encoded no-show keyframe data, wherein the encoded no-show keyframe data includes data indicating that the encoded no-show keyframe data is for a keyframe and data indicating that the encoded no-show keyframe data is for a no-show frame. The encoded bitstream may include encoded overlay frame data corresponding to inter prediction coding using reconstructed no-show keyframe data corresponding to the encoded no-show keyframe data as available reference frame data.

[0007] An aspect is a method for encoding using no-show keyframes. Encoding using no-show keyframes may include obtaining encoded no-show keyframe data, obtaining first encoded subsequent frame data, obtaining encoded overlay frame data, obtaining second encoded subsequent frame data, obtaining encoded forward no-show keyframe data, obtaining third encoded subsequent frame data, obtaining encoded forward overlay frame data, and obtaining fourth encoded subsequent frame data.

[0008] An aspect is an apparatus for encoding using no-show keyframes. The apparatus includes a non-transitory computer readable medium, and a processor configured to execute instructions stored on the non-transitory computer readable medium to obtain encoded no-show keyframe data, obtain first encoded subsequent frame data, obtain encoded overlay frame data, obtain second encoded subsequent frame data, obtain encoded forward no-showkeyframe data, obtain third encoded subsequent frame data, obtain encoded forward overlay frame data, and obtain fourth encoded subsequent frame data.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views unless otherwise noted or otherwise clear from context.

[0010] FIG. 1 is a diagram of a computing device in accordance with implementations of this disclosure.

[0011] FIG. 2 is a diagram of a computing and communications system in accordance with implementations of this disclosure.

[0012] FIG. 3 is a diagram of a video stream for use in encoding and decoding in accordance with implementations of this disclosure.

[0013] FIG. 4 is a block diagram of an encoder in accordance with implementations of this disclosure.

[0014] FIG. 5 is a block diagram of a decoder in accordance with implementations of this disclosure.

[0015] FIG. 6 is a block diagram of a representation of a portion of a frame in accordance with implementations of this disclosure.

[0016] FIG. 7 is a flowchart diagram of an example of decoding using no-show filtered keyframes in accordance with implementations of this disclosure.

[0017] FIG. 8 is a flowchart diagram of an example of encoding using no-show keyframes in accordance with implementations of this disclosure.DETAILED DESCRIPTION

[0018] Image and video compression schemes may include breaking an image, or frame, into smaller portions, such as blocks, and generating an output bitstream using techniques to minimize the bandwidth utilization of the information included for each block in the output. In some implementations, the information included for each block in the output may be limited by reducing spatial redundancy, reducing temporal redundancy, or a combination thereof. For example, temporal or spatial redundancies may be reduced by predicting a frame, or a portion thereof, based on information available to both the encoder and decoder, and including information representing a difference, or residual, between the predicted frame and the original frame in the encoded bitstream. The residual information may be furthercompressed by transforming the residual information into transform coefficients (e.g., energy compaction), quantizing the transform coefficients, and entropy coding the quantized transform coefficients. Other coding information, such as motion information, may be included in the encoded bitstream, which may include transmitting differential information based on predictions of the encoding information, which may be entropy coded to further reduce the corresponding bandwidth utilization. An encoded bitstream can be decoded to reconstruct the blocks and the source images from the limited information. In some implementations, the accuracy, efficiency, or both, of coding a block using either interprediction or intra-prediction may be limited.

[0019] The encoding and decoding using no-show keyframes described herein improves on video coding techniques, or codecs, by coding some keyframes as no-show keyframes, obtaining reconstructed no-show keyframe data by reconstructing the encoded no-show keyframes, and subsequently coding respective overlay frames using inter prediction coding using corresponding reconstructed no-show keyframe data.

[0020] FIG. 1 is a diagram of a computing device 100 in accordance with implementations of this disclosure. The computing device 100 shown includes a memory 110, a processor 120, a user interface (UI) 130, an electronic communication unit 140, a sensor 150, a power source 160, and a bus 170. As used herein, the term “computing device” includes any unit, or a combination of units, capable of performing any method, or any portion or portions thereof, disclosed herein.

[0021] The computing device 100 may be a stationary computing device, such as a personal computer (PC), a server, a workstation, a minicomputer, or a mainframe computer; or a mobile computing device, such as a mobile telephone, a personal digital assistant (PDA), a laptop, or a tablet PC. Although shown as a single unit, any one element or elements of the computing device 100 can be integrated into any number of separate physical units. For example, the user interface 130 and processor 120 can be integrated in a first physical unit and the memory 110 can be integrated in a second physical unit.

[0022] The memory 110 can include any non-transitory computer-usable or computer-readable medium, such as any tangible device that can, for example, contain, store, communicate, or transport data 112, instructions 114, an operating system 116, or any information associated therewith, for use by or in connection with other components of the computing device 100. The non-transitory computer-usable or computer-readable medium can be, for example, a solid-state drive, a memory card, removable media, a read-only memory (ROM), a random-access memory (RAM), any type of disk including a hard disk, afloppy disk, an optical disk, a magnetic or optical card, an application- specific integrated circuits (ASICs), or any type of non-transitory media suitable for storing electronic information, or any combination thereof.

[0023] Although shown a single unit, the memory 110 may include multiple physical units, such as one or more primary memory units, such as random-access memory units, one or more secondary data storage units, such as disks, or a combination thereof. For example, the data 112, or a portion thereof, the instructions 114, or a portion thereof, or both, may be stored in a secondary storage unit and may be loaded or otherwise transferred to a primary storage unit in conjunction with processing the respective data 112, executing the respective instructions 114, or both. In some implementations, the memory 110, or a portion thereof, may be removable memory.

[0024] The data 112 can include information, such as input audio data, encoded audio data, decoded audio data, or the like. The instructions 114 can include directions, such as code, for performing any method, or any portion or portions thereof, disclosed herein. The instructions 114 can be realized in hardware, software, or any combination thereof. For example, the instructions 114 may be implemented as information stored in the memory 110, such as a computer program, which may be executed by the processor 120 to perform any of the respective methods, algorithms, aspects, or combinations thereof, as described herein.

[0025] Although shown as included in the memory 110, in some implementations, the instructions 114, or a portion thereof, may be implemented as a special purpose processor, or circuitry, that can include specialized hardware for carrying out any of the methods, algorithms, aspects, or combinations thereof, as described herein. Portions of the instructions 114 can be distributed across multiple processors on the same machine or different machines or across a network such as a local area network, a wide area network, the Internet, or a combination thereof.

[0026] The processor 120 can include any device or system capable of manipulating or processing a digital signal or other electronic information now-existing or hereafter developed, including optical processors, quantum processors, molecular processors, or a combination thereof. For example, the processor 120 can include a special purpose processor, a central processing unit (CPU), a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessor in association with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a programmable logic array, programmable logic controller, microcode,firmware, any type of integrated circuit (IC), a state machine, or any combination thereof. As used herein, the term “processor” includes a single processor or multiple processors.

[0027] The user interface 130 can include any unit capable of interfacing with a user, such as a virtual or physical keypad, a touchpad, a display, a touch display, a speaker, a microphone, a video camera, a sensor, or any combination thereof. For example, the user interface 130 may be an audio-visual display device, and the computing device 100 may present audio, such as decoded audio, using the user interface 130 audio-visual display device, such as in conjunction with displaying video, such as decoded video. Although shown as a single unit, the user interface 130 may include one or more physical units. For example, the user interface 130 may include an audio interface for performing audio communication with a user, and a touch display for performing visual and touch-based communication with the user.

[0028] The electronic communication unit 140 can transmit, receive, or transmit and receive signals via a wired or wireless electronic communication medium 180, such as a radio frequency (RF) communication medium, an ultraviolet (UV) communication medium, a visible light communication medium, a fiber optic communication medium, a wireline communication medium, or a combination thereof. For example, as shown, the electronic communication unit 140 is operatively connected to an electronic communication interface 142, such as an antenna, configured to communicate via wireless signals.

[0029] Although the electronic communication interface 142 is shown as a wireless antenna in FIG. 1, the electronic communication interface 142 can be a wireless antenna, as shown, a wired communication port, such as an Ethernet port, an infrared port, a serial port, or any other wired or wireless unit capable of interfacing with a wired or wireless electronic communication medium 180. Although FIG. 1 shows a single electronic communication unit 140 and a single electronic communication interface 142, any number of electronic communication units and any number of electronic communication interfaces can be used.

[0030] The sensor 150 may include, for example, an audio-sensing device, a visible lightsensing device, a motion sensing device, or a combination thereof. For example, lOOthe sensor 150 may include a sound-sensing device, such as a microphone, or any other soundsensing device now existing or hereafter developed that can sense sounds in the proximity of the computing device 100, such as speech or other utterances, made by a user operating the computing device 100. In another example, the sensor 150 may include a camera, or any other image-sensing device now existing or hereafter developed that can sense an image such as the image of a user operating the computing device. Although a single sensor 150 isshown, the computing device 100 may include a number of sensors 150. For example, the computing device 100 may include a first camera oriented with a field of view directed toward a user of the computing device 100 and a second camera oriented with a field of view directed away from the user of the computing device 100.

[0031] The power source 160 can be any suitable device for powering the computing device 100. For example, the power source 160 can include a wired external power source interface; one or more dry cell batteries, such as nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion); solar cells; fuel cells; or any other device capable of powering the computing device 100. Although a single power source 160 is shown in FIG. 1, the computing device 100 may include multiple power sources 160, such as a battery and a wired external power source interface.

[0032] Although shown as separate units, the electronic communication unit 140, the electronic communication interface 142, the user interface 130, the power source 160, or portions thereof, may be configured as a combined unit. For example, the electronic communication unit 140, the electronic communication interface 142, the user interface 130, and the power source 160 may be implemented as a communications port capable of interfacing with an external display device, providing communications, power, or both.

[0033] One or more of the memory 110, the processor 120, the user interface 130, the electronic communication unit 140, the sensor 150, or the power source 160, may be operatively coupled via a bus 170. Although a single bus 170 is shown in FIG. 1, a computing device 100 may include multiple buses. For example, the memory 110, the processor 120, the user interface 130, the electronic communication unit 140, the sensor 150, and the bus 170 may receive power from the power source 160 via the bus 170. In another example, the memory 110, the processor 120, the user interface 130, the electronic communication unit 140, the sensor 150, the power source 160, or a combination thereof, may communicate data, such as by sending and receiving electronic signals, via the bus 170.

[0034] Although not shown separately in FIG. 1, one or more of the processor 120, the user interface 130, the electronic communication unit 140, the sensor 150, or the power source 160 may include internal memory, such as an internal buffer or register. For example, the processor 120 may include internal memory (not shown) and may read data 112 from the memory 110 into the internal memory (not shown) for processing.

[0035] Although shown as separate elements, the memory 110, the processor 120, the user interface 130, the electronic communication unit 140, the sensor 150, the power source160, and the bus 170, or any combination thereof can be integrated in one or more electronic units, circuits, or chips.

[0036] FIG. 2 is a diagram of a computing and communications system 200 in accordance with implementations of this disclosure. The computing and communications system 200 shown includes computing and communication devices 100A, 100B, 100C, access points 210A, 210B, and a network 220. For example, the computing and communication system 200 can be a multiple access system that provides communication, such as voice, audio, data, video, messaging, broadcast, or a combination thereof, to one or more wired or wireless communicating devices, such as the computing and communication devices 100A, 100B, 100C. Although, for simplicity, FIG. 2 shows three computing and communication devices 100A, 100B, 100C, two access points 210A, 210B, and one network 220, any number of computing and communication devices, access points, and networks can be used.

[0037] A computing and communication device 100A, 100B, 100C can be, for example, a computing device, such as the computing device 100 shown in FIG. 1. For example, the computing and communication devices 100A, 100B may be user devices, such as a mobile computing device, a laptop, a thin client, or a smartphone, and the computing and communication device 100C may be a server, such as a mainframe or a cluster. Although the computing and communication device 100A and the computing and communication device 100B are described as user devices, and the computing and communication device 100C is described as a server, any computing and communication device may perform some or all of the functions of a server, some, or all, of the functions of a user device, or some or all of the functions of a server and a user device. For example, the server computing and communication device 100C may receive, encode, process, store, transmit, or a combination thereof audio data and one or both of the computing and communication device 100A and the computing and communication device 100B may receive, decode, process, store, present, or a combination thereof the audio data.

[0038] Each computing and communication device 100A, 100B, 100C, which may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a personal computer, a tablet computer, a server, consumer electronics, or any similar device, can be configured to perform wired or wireless communication, such as via the network 220. For example, the computing and communication devices 100A, 100B, 100C can be configured to transmit or receive wired or wireless communication signals. Althougheach computing and communication device 100A, 100B, 100C is shown as a single unit, a computing and communication device can include any number of interconnected elements.

[0039] Each access point 210A, 21 OB can be any type of device configured to communicate with a computing and communication device 100A, 100B, 100C, a network 220, or both via wired or wireless communication links 180A, 180B, 180C. For example, an access point 210A, 210B can include a base station, a base transceiver station (BTS), a Node-B, an enhanced Node-B (eNode-B), a Home Node-B (HNode-B), a wireless router, a wired router, a hub, a relay, a switch, or any similar wired or wireless device. Although each access point 210A, 210B is shown as a single unit, an access point can include any number of interconnected elements.

[0040] The network 220 can be any type of network configured to provide services, such as voice, data, applications, voice over internet protocol (VoIP), or any other communications protocol or combination of communications protocols, over a wired or wireless communication link. For example, the network 220 can be a local area network (FAN), wide area network (WAN), virtual private network (VPN), a mobile or cellular telephone network, the Internet, or any other means of electronic communication. The network can use a communication protocol, such as the transmission control protocol (TCP), the user datagram protocol (UDP), the internet protocol (IP), the real-time transport protocol (RTP) the HyperText Transport Protocol (HTTP), or a combination thereof.

[0041] The computing and communication devices 100A, 100B, 100C can communicate with each other via the network 220 using one or more a wired or wireless communication links, or via a combination of wired and wireless communication links. For example, as shown the computing and communication devices 100A, 100B can communicate via wireless communication links 180A, 180B, and computing and communication device 100C can communicate via a wired communication link 180C. Any of the computing and communication devices 100A, 100B, 100C may communicate using any wired or wireless communication link, or links. For example, a first computing and communication device 100A can communicate via a first access point 210A using a first type of communication link, a second computing and communication device 100B can communicate via a second access point 210B using a second type of communication link, and a third computing and communication device 100C can communicate via a third access point (not shown) using a third type of communication link. Similarly, the access points 210A, 210B can communicate with the network 220 via one or more types of wired or wireless communication links 230A, 230B. Although FIG. 2 shows the computing and communication devices 100A, 100B, 100Cin communication via the network 220, the computing and communication devices 100A, 100B, 100C can communicate with each other via any number of communication links, such as a direct wired or wireless communication link.

[0042] In some implementations, communications between one or more of the computing and communication device 100A, 100B, 100C may omit communicating via the network 220 and may include transferring data via another medium (not shown), such as a data storage device. For example, the server computing and communication device 100C may store audio data, such as encoded audio data, in a data storage device, such as a portable data storage unit, and one or both of the computing and communication device 100A or the computing and communication device 100B may access, read, or retrieve the stored audio data from the data storage unit, such as by physically disconnecting the data storage device from the server computing and communication device 100C and physically connecting the data storage device to the computing and communication device 100A or the computing and communication device 100B.

[0043] Other implementations of the computing and communications system 200 are possible. For example, in an implementation, the network 220 can be an ad-hoc network and can omit one or more of the access points 210A, 210B. The computing and communications system 200 may include devices, units, or elements not shown in FIG. 2. For example, the computing and communications system 200 may include many more communicating devices, networks, and access points.

[0044] FIG. 3 is a diagram of a video stream 300 for use in encoding and decoding in accordance with implementations of this disclosure. A video stream 300, such as a video stream captured by a video camera or a video stream generated by a computing device, may include a video sequence 310. The video sequence 310 may include a sequence of adjacent frames 320. Although three adjacent frames 320 are shown, the video sequence 310 can include any number of adjacent frames 320.

[0045] Each frame 330 from the adjacent frames 320 may represent a single image from the video stream. Although not shown in FIG. 3, a frame 330 may include one or more segments, tiles, or planes, which may be coded, or otherwise processed, independently, such as in parallel. A frame 330 may include one or more tiles 340. Each of the tiles 340 may be a rectangular region of the frame that can be coded independently. Each of the tiles 340 may include respective blocks 350. Although not shown in FIG. 3, a block can include pixels. For example, a block can include a 16x16 group of pixels, an 8x8 group of pixels, an 8x16 group of pixels, or any other group of pixels. Unless otherwise indicated herein, the term ‘block’can include a superblock, a macroblock, a segment, a slice, or any other portion of a frame. A frame, a block, a pixel, or a combination thereof can include display information, such as luminance information, chrominance information, or any other information that can be used to store, modify, communicate, or display the video stream or a portion thereof.

[0046] FIG. 4 is a block diagram of an encoder 400 in accordance with implementations of this disclosure. Encoder 400 can be implemented in a device, such as the computing device 100 shown in FIG. 1 or the computing and communication devices 100A, 100B, 100C shown in FIG. 2, as, for example, a computer software program stored in a data storage unit, such as the memory 110 shown in FIG. 1. The computer software program can include machine instructions that may be executed by a processor, such as the processor 120 shown in FIG. 1, and may cause the device to encode video data as described herein. The encoder 400 can be implemented as specialized hardware included, for example, in computing device 100.

[0047] The encoder 400 can encode an input video stream 402, such as the video stream 300 shown in FIG. 3, to generate an encoded (compressed) bitstream 404. In some implementations, the encoder 400 may include a forward path for generating the compressed bitstream 404. The forward path may include an intra / inter prediction unit 410, a transform unit 420, a quantization unit 430, an entropy encoding unit 440, or any combination thereof. In some implementations, the encoder 400 may include a reconstruction path (indicated by the broken connection lines) to reconstruct a frame for encoding of further blocks. The reconstruction path may include a dequantization unit 450, an inverse transform unit 460, a reconstruction unit 470, a filtering unit 480, or any combination thereof. Other structural variations of the encoder 400 can be used to encode the video stream 402.

[0048] For encoding the video stream 402, each frame within the video stream 402 can be processed in units of blocks. Thus, a current block may be identified from the blocks in a frame, and the current block may be encoded.

[0049] At the intra / inter prediction unit 410, the current block can be encoded using either intra-frame prediction, which may be within a single frame, or inter-frame prediction, which may be from frame to frame. Intra-prediction may include generating a prediction block from samples in the current frame that have been previously encoded and reconstructed. Inter-prediction may include generating a prediction block from samples in one or more previously constructed reference frames. Generating a prediction block for a current block in a current frame may include performing motion estimation to generate a motion vector indicating an appropriate reference portion of the reference frame.

[0050] The intra / inter prediction unit 410 may subtract the prediction block from the current block (raw block) to produce a residual block. The transform unit 420 may perform a block-based transform, which may include transforming the residual block into transform coefficients in, for example, the frequency domain. Examples of block-based transforms include the Karhunen-Loeve Transform (KLT), the Discrete Cosine Transform (DCT), the Singular Value Decomposition Transform (SVD), and the Asymmetric Discrete Sine Transform (ADST). In an example, the DCT may include transforming a block into the frequency domain. The DCT may include using transform coefficient values based on spatial frequency, with the lowest frequency (i.e., direct current (DC)) coefficient at the top-left of the matrix and the highest frequency coefficient at the bottom-right of the matrix.

[0051] The quantization unit 430 may convert the transform coefficients into discrete quantum values, which may be referred to as quantized transform coefficients or quantization levels. The quantized transform coefficients can be entropy encoded by the entropy encoding unit 440 to produce entropy-encoded coefficients. Entropy encoding can include using a probability distribution metric. The entropy-encoded coefficients and information used to decode the block, which may include the type of prediction used, motion vectors, and quantizer values, can be output to the compressed bitstream 404. The compressed bitstream 404 can be formatted using various techniques, such as run-length encoding (RLE) and zerorun coding.

[0052] The reconstruction path can be used to maintain reference frame synchronization between the encoder 400 and a corresponding decoder, such as the decoder 500 shown in FIG. 5. The reconstruction path may be similar to the decoding process discussed below and may include decoding the encoded frame, or a portion thereof, which may include decoding an encoded block, which may include dequantizing the quantized transform coefficients at the dequantization unit 450 and inverse transforming the dequantized transform coefficients at the inverse transform unit 460 to produce a derivative residual block. The reconstruction unit 470 may add the prediction block generated by the intra / inter prediction unit 410 to the derivative residual block to create a decoded block. The filtering unit 480 can be applied to the decoded block to generate a reconstructed block, which may reduce distortion, such as blocking artifacts. Although one filtering unit 480 is shown in FIG. 4, filtering the decoded block may include loop filtering, deblocking filtering, or other types of filtering or combinations of types of filtering. The reconstructed block may be stored or otherwise made accessible as a reconstructed block, which may be a portion of a reference frame, for encoding another portion of the current frame, another frame, or both, as indicated by thebroken line at 482. Coding information, such as deblocking threshold index values, for the frame may be encoded, included in the compressed bitstream 404, or both, as indicated by the broken line at 484.

[0053] Other variations of the encoder 400 can be used to encode the compressed bitstream 404. For example, a non-transform-based encoder 400 can quantize the residual block directly without the transform unit 420. In some implementations, the quantization unit 430 and the dequantization unit 450 may be combined into a single unit.

[0054] FIG. 5 is a block diagram of a decoder 500 in accordance with implementations of this disclosure. The decoder 500 can be implemented in a device, such as the computing device 100 shown in FIG. 1 or the computing and communication devices 100A, 100B, 100C shown in FIG. 2, as, for example, a computer software program stored in a data storage unit, such as the memory 110 shown in FIG. 1. The computer software program can include machine instructions that may be executed by a processor, such as the processor 120 shown in FIG. 1, and may cause the device to decode video data as described herein. The decoder 500 can be implemented as specialized hardware included, for example, in computing device 100.

[0055] The decoder 500 may receive a compressed bitstream 502, such as the compressed bitstream 404 shown in FIG. 4, and may decode the compressed bitstream 502 to generate an output video stream 504. The decoder 500 may include an entropy decoding unit 510, a dequantization unit 520, an inverse transform unit 530, an intra / inter prediction unit 540, a reconstruction unit 550, a filtering unit 560, or any combination thereof. Other structural variations of the decoder 500 can be used to decode the compressed bitstream 502.

[0056] The entropy decoding unit 510 may decode data elements within the compressed bitstream 502 using, for example, Context Adaptive Binary Arithmetic Decoding, to produce a set of quantized transform coefficients. The dequantization unit 520 can dequantize the quantized transform coefficients, and the inverse transform unit 530 can inverse transform the dequantized transform coefficients to produce a derivative residual block, which may correspond to the derivative residual block generated by the inverse transform unit 460 shown in FIG. 4. Using header information decoded from the compressed bitstream 502, the intra / inter prediction unit 540 may generate a prediction block corresponding to the prediction block created in the encoder 400. At the reconstruction unit 550, the prediction block can be added to the derivative residual block to create a decoded block. The filtering unit 560 can be applied to the decoded block to reduce artifacts, such as blocking artifacts, which may include loop filtering, deblocking filtering, or other types of filtering orcombinations of types of filtering, and which may include generating a reconstructed block, which may be output as the output video stream 504.

[0057] Other variations of the decoder 500 can be used to decode the compressed bitstream 502. For example, the decoder 500 can produce the output video stream 504 without the deblocking filtering unit 560.

[0058] FIG. 6 is a block diagram of a representation of a portion 600 of a frame, such as the frame 330 shown in FIG. 3, in accordance with implementations of this disclosure. As shown, the portion 600 of the frame includes four 64x64 blocks 610, in two rows and two columns in a matrix or Cartesian plane. In some implementations, a 64x64 block may be a maximum coding unit, N=64. Each 64x64 block may include four 32x32 blocks 620. Each 32x32 block may include four 16x16 blocks 630. Each 16x16 block may include four 8x8 blocks 640. Each 8x8 block 640 may include four 4x4 blocks 650. Each 4x4 block 650 may include 16 pixels, which may be represented in four rows and four columns in each respective block in the Cartesian plane or matrix. The pixels may include information representing an image captured in the frame, such as luminance information, color information, and location information. In some implementations, a block, such as a 16x16 pixel block as shown, may include a luminance block 660, which may include luminance pixels 662; and two chrominance blocks 670, 680, such as a U or Cb chrominance block 670, and a V or Cr chrominance block 680. The chrominance blocks 670, 680 may include chrominance pixels 690. For example, the luminance block 660 may include 16x16 luminance pixels 662 and each chrominance block 670, 680 may include 8x8 chrominance pixels 690 as shown.Although one arrangement of blocks is shown, any arrangement may be used. Although FIG.6 shows NxN blocks, in some implementations, NxM blocks may be used. For example, 32x64 blocks, 64x32 blocks, 16x32 blocks, 32x16 blocks, or any other size blocks may be used. In some implementations, Nx2N blocks, 2NxN blocks, or a combination thereof may be used.

[0059] In some implementations, video coding may include ordered block-level coding. Ordered block-level coding may include coding blocks of a frame in an order, such as rasterscan order, wherein blocks may be identified and processed starting with a block in the upper left comer of the frame, or portion of the frame, and proceeding along rows from left to right and from the top row to the bottom row, identifying each block in turn for processing. For example, the 64x64 block in the top row and left column of a frame may be the first block coded and the 64x64 block immediately to the right of the first block may be the second block coded. The second row from the top may be the second row coded, such that the 64x64block in the left column of the second row may be coded after the 64x64 block in the rightmost column of the first row.

[0060] In some implementations, coding a block may include using quad-tree coding, which may include coding smaller block units within a block in raster- scan order. For example, the 64x64 block shown in the bottom left comer of the portion of the frame shown in FIG. 6, may be coded using quad-tree coding wherein the top left 32x32 block may be coded, then the top right 32x32 block may be coded, then the bottom left 32x32 block may be coded, and then the bottom right 32x32 block may be coded. Each 32x32 block may be coded using quad- tree coding wherein the top left 16x16 block may be coded, then the top right 16x16 block may be coded, then the bottom left 16x16 block may be coded, and then the bottom right 16x16 block may be coded. Each 16x16 block may be coded using quad- tree coding wherein the top left 8x8 block may be coded, then the top right 8x8 block may be coded, then the bottom left 8x8 block may be coded, and then the bottom right 8x8 block may be coded. Each 8x8 block may be coded using quad-tree coding wherein the top left 4x4 block may be coded, then the top right 4x4 block may be coded, then the bottom left 4x4 block may be coded, and then the bottom right 4x4 block may be coded. In some implementations, 8x8 blocks may be omitted for a 16x16 block, and the 16x16 block may be coded using quad-tree coding wherein the top left 4x4 block may be coded, then the other 4x4 blocks in the 16x16 block may be coded in raster- scan order.

[0061] In some implementations, video coding may include compressing the information included in an original, or input, frame by, for example, omitting some of the information in the original frame from a corresponding encoded frame. For example, coding may include reducing spectral redundancy, reducing spatial redundancy, reducing temporal redundancy, or a combination thereof.

[0062] In some implementations, reducing spectral redundancy may include using a color model based on a luminance component (Y) and two chrominance components (U and V or Cb and Cr), which may be referred to as the YUV or YCbCr color model, or color space. Using the YUV color model may include using a relatively large amount of information to represent the luminance component of a portion of a frame and using a relatively small amount of information to represent each corresponding chrominance component for the portion of the frame. For example, a portion of a frame may be represented by a high-resolution luminance component, which may include a 16x16 block of pixels, and by two lower resolution chrominance components, each of which represents the portion of the frame as an 8x8 block of pixels. A pixel may indicate a value, for example, a value in the rangefrom 0 to 255, and may be stored or transmitted using, for example, eight bits. Although this disclosure is described in reference to the YUV color model, any color model may be used.

[0063] In some implementations, reducing spatial redundancy may include transforming a block into the frequency domain using, for example, a discrete cosine transform (DCT). For example, a unit of an encoder, such as the transform unit 420 shown in FIG. 4, may perform a DCT using transform coefficient values based on spatial frequency.

[0064] In some implementations, reducing temporal redundancy may include using similarities between frames to encode a frame using a relatively small amount of data based on one or more reference frames, which may be previously encoded, decoded, and reconstructed frames of the video stream. For example, a block or pixel of a current frame may be similar to a spatially corresponding block or pixel of a reference frame. In some implementations, a block or pixel of a current frame may be similar to block or pixel of a reference frame at a different spatial location and reducing temporal redundancy may include generating motion information indicating the spatial difference, or translation, between the location of the block or pixel in the current frame and corresponding location of the block or pixel in the reference frame.

[0065] In some implementations, reducing temporal redundancy may include identifying a portion of a reference frame that corresponds to a current block or pixel of a current frame. For example, a reference frame, or a portion of a reference frame, which may be stored in memory, may be searched to identify a portion for generating a prediction to use for encoding a current block or pixel of the current frame with maximal efficiency. For example, the search may identify a portion of the reference frame for which the difference in pixel values between the current block and a prediction block generated based on the portion of the reference frame is minimized and may be referred to as motion searching. In some implementations, the portion of the reference frame searched may be limited. For example, the portion of the reference frame searched, which may be referred to as the search area, may include a limited number of rows of the reference frame. In an example, identifying the portion of the reference frame for generating a prediction may include calculating a cost function, such as a sum of absolute differences (SAD), between the pixels of portions of the search area and the pixels of the current block.

[0066] In some implementations, the spatial difference between the location of the portion of the reference frame for generating a prediction in the reference frame and the current block in the current frame may be represented as a motion vector. The difference in pixel values between the prediction block and the current block may be referred to asdifferential data, residual data, a prediction error, or as a residual block. In some implementations, generating motion vectors may be referred to as motion estimation, and a pixel of a current block may be indicated based on location using Cartesian coordinates as / (.y. Similarly, a pixel of the search area of the reference frame may be indicated based on location using Cartesian coordinates as rx,y. A motion vector (MV) for the current block may be determined based on, for example, a SAD between the pixels of the current frame and the corresponding pixels of the reference frame.

[0067] Although described herein with reference to matrix or Cartesian representation of a frame for clarity, a frame may be stored, transmitted, processed, or any combination thereof, in any data structure such that pixel values may be efficiently represented for a frame or image. For example, a frame may be stored, transmitted, processed, or any combination thereof, in a two-dimensional data structure such as a matrix as shown, or in a onedimensional data structure, such as a vector array. In an implementation, a representation of the frame, such as a two-dimensional representation as shown, may correspond to a physical location in a rendering of the frame as an image. For example, a location in the top left corner of a block in the top left comer of the frame may correspond with a physical location in the top left corner of a rendering of the frame as an image.

[0068] In some implementations, block-based coding efficiency may be improved by partitioning input blocks into one or more prediction partitions, which may be rectangular, including square, partitions for prediction coding. In some implementations, video coding using prediction partitioning may include selecting a prediction partitioning scheme from among multiple candidate prediction partitioning schemes. For example, in some implementations, candidate prediction partitioning schemes for a 64x64 coding unit may include rectangular size prediction partitions ranging in sizes from 4x4 to 64x64, such as 4x4, 4x8, 8x4, 8x8, 8x16, 16x8, 16x16, 16x32, 32x16, 32x32, 32x64, 64x32, or 64x64. In some implementations, video coding using prediction partitioning may include a full prediction partition search, which may include selecting a prediction partitioning scheme by encoding the coding unit using each available candidate prediction partitioning scheme and selecting the best scheme, such as the scheme that produces the least rate-distortion error.

[0069] In some implementations, encoding a video frame may include identifying a prediction partitioning scheme for encoding a current block, such as block 610. In some implementations, identifying a prediction partitioning scheme may include determining whether to encode the block as a single prediction partition of maximum coding unit size,which may be 64x64 as shown, or to partition the block into multiple prediction partitions, which may correspond with the sub-blocks, such as the 32x32 blocks 620 the 16x16 blocks 630, or the 8x8 blocks 640, as shown, and may include determining whether to partition into one or more smaller prediction partitions. For example, a 64x64 block may be partitioned into four 32x32 prediction partitions. Three of the four 32x32 prediction partitions may be encoded as 32x32 prediction partitions and the fourth 32x32 prediction partition may be further partitioned into four 16x16 prediction partitions. Three of the four 16x16 prediction partitions may be encoded as 16x16 prediction partitions and the fourth 16x16 prediction partition may be further partitioned into four 8x8 prediction partitions, each of which may be encoded as an 8x8 prediction partition. In some implementations, identifying the prediction partitioning scheme may include using a prediction partitioning decision tree.

[0070] In some implementations, video coding for a current block may include identifying an optimal prediction coding mode from multiple candidate prediction coding modes, which may provide flexibility in handling video signals with various statistical properties and may improve the compression efficiency. For example, a video coder may evaluate each candidate prediction coding mode to identify the optimal prediction coding mode, which may be, for example, the prediction coding mode that minimizes an error metric, such as a rate-distortion cost, for the current block. In some implementations, the complexity of searching the candidate prediction coding modes may be reduced by limiting the set of available candidate prediction coding modes based on similarities between the current block and a corresponding prediction block. In some implementations, the complexity of searching each candidate prediction coding mode may be reduced by performing a directed refinement mode search. For example, metrics may be generated for a limited set of candidate block sizes, such as 16x16, 8x8, and 4x4, the error metric associated with each block size may be in descending order, and additional candidate block sizes, such as 4x8 and 8x4 block sizes, may be evaluated.

[0071] In some implementations, block-based coding efficiency may be improved by partitioning a current residual block into one or more transform partitions, which may be rectangular, including square, partitions for transform coding. In some implementations, video coding, such as video coding using transform partitioning, may include selecting a uniform transform partitioning scheme. For example, a current residual block, such as block 610, may be a 64x64 block and may be transformed without partitioning using a 64x64 transform.

[0072] Although not expressly shown in FIG. 6, a residual block may be transform partitioned using a uniform transform partitioning scheme. For example, a 64x64 residual block may be transform partitioned using a uniform transform partitioning scheme including four 32x32 transform blocks, using a uniform transform partitioning scheme including sixteen 16x16 transform blocks, using a uniform transform partitioning scheme including sixty-four 8x8 transform blocks, or using a uniform transform partitioning scheme including 2564x4 transform blocks.

[0073] In some implementations, video coding, such as video coding using transform partitioning, may include identifying multiple transform block sizes for a residual block using multiform transform partition coding. In some implementations, multiform transform partition coding may include recursively determining whether to transform a current block using a current block size transform or by partitioning the current block and multiform transform partition coding each partition. For example, the bottom left block 610 shown in FIG. 6 may be a 64x64 residual block, and multiform transform partition coding may include determining whether to code the current 64x64 residual block using a 64x64 transform or to code the 64x64 residual block by partitioning the 64x64 residual block into partitions, such as four 32x32 blocks 620, and multiform transform partition coding each partition. In some implementations, determining whether to transform partition the current block may be based on comparing a cost for encoding the current block using a current block size transform to a sum of costs for encoding each partition using partition size transforms.

[0074] FIG. 7 is a flowchart diagram of an example of decoding using no-show filtered keyframes 700 in accordance with implementations of this disclosure. Decoding using no-show keyframes 700 may be implemented in a decoder, such as the decoder 500 shown in FIG. 5.

[0075] Decoding using no-show keyframes 700 includes decoding an encoded bitstream, such as the compressed bitstream 502 shown in FIG. 5, or one or more portions thereof, to generate a reconstructed video, or a portion thereof, such as the output video stream 504 shown in FIG. 5.

[0076] A keyframe (key frame or key_frame) is an intra prediction coded (intra-coded) frame, which is coded independently of other frames.

[0077] For example, decoding a 1020thframe of a sequence of frames randomly, or ad-hoc, wherein the 1000thframe of the sequence of frames is a keyframe, may omit decoding frames from the sequence of frames prior to the 1000thframe, in coding order, and mayinclude decoding the 1000thframe (keyframe) and subsequent frames to decode the 1020thframe.

[0078] A keyframe is a key frame random-access point, a delayed random-access point, a no-show keyframe random-access point, or a forward filtered no-show key frame randomaccess point.

[0079] A key frame random- access point is a frame wherein encoded frame data for the key frame random-access point indicates that frame is a keyframe, and wherein encoded frame data for the key frame random-access point indicates that a reconstructed frame corresponding to a key frame random-access point is output for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, which may be expressed as show_frame == 1. A reconstructed frame corresponding to a key frame random-access point is included in a reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order.

[0080] A delayed random-access point is a keyframe that is coded prior, in coding order, to the temporal, display, or input order of the keyframe so that the corresponding reconstructed keyframe (forward keyframe) may be used as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are prior to the keyframe in temporal, display, or input order. Encoded frame data for the delayed random-access point frame indicates that the frame is a keyframe. Encoded frame data for the delayed randomaccess point frame indicates that outputting a reconstructed frame corresponding to a delayed random-access point for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, is omitted, skipped, or avoided, which may be expressed as show_frame == 0. A reconstructed frame corresponding to a delayed random-access point is included in a reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are prior to or subsequent to the keyframe in temporal, display, or input order. A delayed random-access point keyframe is a showable frame (showable_frame == 1).

[0081] A no-show key frame random-access point (filtered keyframe or no-show keyframe) is a frame wherein encoded frame data for the no-show key frame random-access point indicates that frame is a keyframe (the encoded frame data is for a keyframe), and wherein the encoded frame data for the no-show key frame random-access point indicates that outputting a reconstructed frame corresponding to the no-show key frame random-accesspoint for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, is omitted, skipped, or avoided, which may be expressed as show_frame == 0. A no-show key frame random-access point is other than a showable frame (showable_frame == 0). In some implementations, the encoded frame data for the no-show key frame random-access point indicates an order hint value (order_hint) of zero (order_hint == 0). A reconstructed frame corresponding to a no-show key frame random-access point is included in a reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order. In some implementations, reconstructing the no-show key frame random-access point includes the refreshing of reference frames (refresh_frame_flags = (1 << REF_FRAMES) - 1), such that reference frames, other than the reconstructed frame corresponding to a no-show key frame random-access point, are removed, deleted, omitted, or excluded from the reference frame buffer.

[0082] A forward filtered no-show key frame random-access point (forward filtered keyframe or forward no-show keyframe) is a frame wherein encoded frame data for the forward filtered no-show key frame random-access point indicates that frame is a keyframe, and wherein the encoded frame data for the forward filtered no-show key frame randomaccess point indicates that outputting a reconstructed frame corresponding to the forward filtered no-show key frame random- access point for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, is omitted, skipped, or avoided, which may be expressed as show_frame == 0. A reconstructed frame corresponding to a forward filtered no-show key frame randomaccess point may be used as a reference frame for decoding a subsequent forward filtered key frame dependent overlay frame. A forward filtered no-show key frame random-access point is other than a showable frame (showable_frame == 0). In some implementations, the encoded frame data for the forward filtered no-show key frame random-access point indicates an order hint value (order_hint) that is one greater than a most recently coded order hint value. A reconstructed frame corresponding to the forward filtered no-show key frame random-access point is included in a reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order. In some implementations, the encoded frame data for the forward filtered no-show key frame random-access point includes one or more bits, flags, or other syntax elements indicating zero or more reference frames to refresh, orreplace, with the reconstructed frame corresponding to the forward filtered no-show key frame random-access point.

[0083] A key frame dependent recovery point is a frame wherein the encoded frame data for the key frame dependent recovery point omits encoded image data and includes data, such as a bit, flag, or other syntax element that indicates the output, presentation, or display of a previously reconstructed delayed random-access point keyframe, which may be expressed as show_existing_frame == 1. The encoded frame data for the key frame dependent recovery point includes data, such as a defined number, count, or cardinality of bits, such as three bits, (frame_to_show_map_idx) indicating an index value of a frame from the reference frame buffer to be shown in accordance with decoding the key frame dependent recovery point.

[0084] A key frame dependent overlay frame (overlay frame) is an inter prediction coded frame coded using previously reconstructed no-show keyframe data, from the reference frame buffer, as available reference frame data, wherein encoded frame data for the key frame dependent overlay frame includes data, such as a bit, flag, or other syntax element that indicates the output, presentation, or display of a previously reconstructed frame is omitted, skipped, or excluded, which may be expressed as show_existing_frame == 0. In some implementations, the encoded frame data for the key frame dependent overlay frame includes data, such as a bit, flag, or other syntax element that indicates that a reconstructed frame corresponding to a key frame dependent overlay frame is output for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, which may be expressed as show_frame == 1. In some implementations, the encoded frame data for the key frame dependent overlay frame indicates an order hint value (order_hint) of zero (order_hint == 0). In some implementations, reconstructing the key frame dependent overlay frame includes omitting, skipping, or excluding refreshing reference frames (refresh_frame_flags == 0). In some implementations, including the reconstructed frame corresponding to the forward filtered no-show key frame random-access point in the reference frame buffer for use as a reference frame may be omitted, skipped, avoided, or excluded.

[0085] A forward filtered key frame dependent overlay frame (forward overlay frame) is an inter prediction coded frame coded using previously reconstructed forward filtered no-show keyframe data, from the reference frame buffer as available reference frame data, wherein encoded frame data for the forward filtered key frame dependent overlay frame includes data, such as a bit, flag, or other syntax element that indicates the output, presentation, or display of a previously reconstructed frame is omitted, skipped, or excluded,which may be expressed as show_existing_frame == 0. In some implementations, In some implementations, the encoded frame data for the forward filtered key frame dependent overlay frame includes data, such as a bit, flag, or other syntax element that indicates that a reconstructed frame corresponding to a forward filtered key frame dependent overlay frame is output for display in response to, or in accordance with, decoding, or reconstructing, the frame, such as prior to decoding, or reconstructing, a subsequent frame, which may be expressed as show_frame == 1. In some implementations, the encoded frame data for the forward filtered key frame dependent overlay frame indicates an order hint value (order_hint) of zero (order_hint == 0). In some implementations, reconstructing the forward filtered key frame dependent overlay frame includes determining that the forward filtered key frame dependent overlay frame is an inter prediction coded frame, the order hint value is zero, and that a frame reconstructed prior, such as immediately prior, to reconstructing the forward filtered key frame dependent overlay frame is other than a keyframe, which may be expressed as the following:if(frame_ type == INTER_FRAME && order_hint == 0 && last_frame_ type !=KEY_FRAME)

[0086] In some implementations, the encoded frame data for the forward filtered key frame dependent overlay frame includes data, such as a bit, flag, or other syntax element that indicates a location, such as an index value with respect to the reference frame buffer, of a corresponding forward filtered no-show key frame random-access point. In response to determining that the forward filtered key frame dependent overlay frame is an inter prediction coded frame, the order hint value is zero, and that a frame reconstructed prior, such as immediately prior, to reconstructing the forward filtered key frame dependent overlay frame is other than a keyframe, the forward filtered key frame dependent overlay frame is identified as such and the bit, flag, or other syntax element that indicates a location, such as an index value with respect to the reference frame buffer, of a corresponding forward filtered no-show key frame random-access point is obtained. In some implementations, reconstructing the forward filtered key frame dependent overlay frame includes refreshing the reference frame buffer, such that reference frames, other than the reconstructed frame corresponding to the corresponding forward filtered no-show key frame random-access point, are removed, deleted, omitted, or excluded from the reference frame buffer.

[0087] In some implementations, a random-access point, or recovery point, corresponding to a key frame dependent overlay frame is a first frame, in temporal, display,or output order, for which the previously reconstructed no-show keyframe data is available reference frame data.

[0088] In some implementations, a random-access point, or recovery point, corresponding to a key frame dependent overlay frame is a first frame, in temporal, display, or output order, subsequent to, in coding order, a no-show keyframe.

[0089] In some implementations, a random-access point, or recovery point, corresponding to a key frame dependent overlay frame is a frame wherein the encoded frame data for the frame includes a bit, flag, or other syntax element that indicates that the frame is the random-access point, or recovery point, which may be expressed as is_kf_dependent_recovery_point == 1.

[0090] Decoding using no-show keyframes 700 includes obtaining reconstructed no-show keyframe data (at 710), obtaining first reconstructed subsequent frame data (at 720), obtaining reconstructed overlay frame data (at 730), obtaining second reconstructed subsequent frame data (at 740), obtaining reconstructed forward no-show keyframe data (at 750), obtaining third reconstructed subsequent frame data (at 760), obtaining reconstructed forward overlay frame data (at 770), and obtaining fourth reconstructed subsequent frame data (at 780). Decoding using no-show keyframes 700 may include aspects not expressly shown in FIG. 7 for simplicity, such as filtering, such as the filtering shown (at 560) in FIG.5.

[0091] Although FIG. 7 shows obtaining reconstructed no-show keyframe data (at 710), obtaining first reconstructed subsequent frame data (at 720), obtaining reconstructed overlay frame data (at 730), obtaining second reconstructed subsequent frame data (at 740), obtaining reconstructed forward no-show keyframe data (at 750), obtaining third reconstructed subsequent frame data (at 760), obtaining reconstructed forward overlay frame data (at 770), and obtaining fourth reconstructed subsequent frame data (at 780), obtaining reconstructed no-show keyframe data (at 710), obtaining first reconstructed subsequent frame data (at 720), obtaining reconstructed overlay frame data (at 730), and obtaining second reconstructed subsequent frame data (at 740), may be performed in the absence of obtaining reconstructed forward no-show keyframe data (at 750), obtaining third reconstructed subsequent frame data (at 760), obtaining reconstructed forward overlay frame data (at 770), and obtaining fourth reconstructed subsequent frame data (at 780).

[0092] Although FIG. 7 shows obtaining reconstructed no-show keyframe data (at 710), obtaining first reconstructed subsequent frame data (at 720), obtaining reconstructed overlay frame data (at 730), obtaining second reconstructed subsequent frame data (at 740), obtainingreconstructed forward no-show keyframe data (at 750), obtaining third reconstructed subsequent frame data (at 760), obtaining reconstructed forward overlay frame data (at 770), and obtaining fourth reconstructed subsequent frame data (at 780), obtaining reconstructed no-show keyframe data (at 710), obtaining first reconstructed subsequent frame data (at 720), and obtaining reconstructed overlay frame data (at 730), may be omitted, skipped, avoided, or excluded.

[0093] To obtain the reconstructed no-show keyframe data (at 710), the decoder extracts, reads, obtains, or otherwise accesses encoded no-show keyframe data (at 710) from the encoded bitstream. The encoded no-show keyframe data includes a bit, flag, or other syntax element, indicating that the encoded no-show keyframe data is for a keyframe. The encoded no-show keyframe data includes a bit, flag, or other syntax element, indicating that the encoded no-show keyframe data is for a no-show frame.

[0094] To obtain the reconstructed no-show keyframe data (at 710), the decoder decodes the encoded no-show keyframe data using intra prediction coding and reconstructs the reconstructed no-show keyframe data (a reconstructed no-show keyframe). The decoder accesses, from the encoded no-show keyframe data, the bit, flag, or other syntax element indicating that the reconstructed no-show keyframe is a keyframe. The decoder accesses, from the encoded no-show keyframe data, the bit, flag, or other syntax element indicating that the reconstructed no-show keyframe is a no-show frame (show_frame == 0 and showable_frame == 0). In some implementations, the decoder accesses from the encoded no-show keyframe data, the bit, flag, or other syntax element indicating an order hint value (order_hint) of zero (order_hint == 0).

[0095] The decoder includes the reconstructed no-show keyframe data in the reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order. In some implementations, the decoder removes, deletes, omits, or excludes reference frames, other than the reconstructed frame corresponding to a no-show key frame randomaccess point, from the reference frame buffer.

[0096] The decoder omits, avoids, or excludes outputting the reconstructed no-show keyframe for presentation or display.

[0097] To obtain the first reconstructed subsequent frame data (at 720), the decoder accesses first encoded subsequent frame data (at 720) from the encoded bitstream for one or more subsequent frames, such as subsequent to the encoded no-show keyframe data in the encoded bitstream. The first encoded subsequent frame data is encoded frame data for one ormore frames respectively coded as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed no-show keyframe data as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data as available reference frame data, a respective frame corresponding to the first encoded subsequent frame data may be reconstructed using other previously reconstructed reference frame data as available reference frame data.

[0098] The decoder obtains, from the first encoded subsequent frame data, on a per-frame basis, a bit, flag, or other syntax element indicating that reconstructing the respective frame omits, excludes, or avoids outputting the frame for display, which may be expressed as show_frame == 0.

[0099] To obtain the first reconstructed subsequent frame data (at 720), the decoder decodes the first encoded subsequent frame data using the reconstructed no-show keyframe data as available reference frame data. The first reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data as available reference frame data. The decoder may include the reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0100] Obtaining the first reconstructed subsequent frame data omits, skips, avoids, or excludes outputting the reconstructed subsequent frame data.

[0101] Obtaining the first reconstructed subsequent frame data may include obtaining reconstructed subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining first reconstructed subsequent frame data (at 720) to obtaining first reconstructed subsequent frame data (at 720).

[0102] To obtain the reconstructed overlay frame data (at 730), the decoder accesses encoded overlay frame data (at 730) from the encoded bitstream, such as subsequent to accessing the encoded subsequent frame data (at 720).

[0103] The decoder obtains, from the encoded overlay frame data, a bit, flag, or other syntax element indicating that reconstructing the overlay frame data includes outputting the corresponding reconstructed frame for display, or otherwise indicating the output (data indicating output) of the reconstructed overlay frame data in response to decoding the encoded overlay frame data, which may be expressed as show_frame == 1.

[0104] In some implementations, the decoder accesses from the encoded overlay frame data, the bit, flag, or other syntax element indicating an order hint value (order_hint) of zero (order_hint == 0).

[0105] To obtain the reconstructed overlay frame data (at 730), the decoder decodes the encoded overlay frame data using inter prediction coding using the reconstructed no-show keyframe data as available reference frame data and reconstructs the reconstructed overlay frame data (a reconstructed overlay frame).

[0106] The decoder includes the reconstructed frame data obtained by decoding the encoded overlay frame data in output data for presentation or display.

[0107] In some implementations, the decoder may omit, skip, avoid, or exclude including the reconstructed overlay frame data in the reference frame buffer.

[0108] Although not expressly shown in FIG. 7, subsequent to decoding the encoded overlay frame data, the decoder may access encoded frame data that omits, or excludes, encoded image data and includes data, such as a bit, flag, or other syntax element that indicates the output, presentation, or display of a previously reconstructed frame obtained by decoding the first encoded subsequent frame data, which may be expressed as show_existing_frame == 1, wherein the encoded frame data includes data, such as a defined number, count, or cardinality of bits, such as three bits, (frame_to_show_map_idx) indicating an index value of a frame from the reference frame buffer to be shown. The decoder includes the reconstructed frame data indicated by the index value in the output data for presentation or display.

[0109] The decoder obtains second reconstructed subsequent frame data (at 740). To obtain the second reconstructed subsequent frame data (at 740), the decoder accesses second encoded subsequent frame data (at 740) from the encoded bitstream for one or more subsequent frames, such as subsequent to the encoded overlay frame data in the encoded bitstream. The second encoded subsequent frame data is encoded frame data for one or more frames respectively coded as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using inter prediction using the reconstructed no-show keyframe data as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data as available reference frame data, a respective frame corresponding to the second encoded subsequent frame data may be reconstructed using other previously reconstructed reference frame data as available reference frame data.

[0110] To obtain the second reconstructed subsequent frame data (at 740), the decoder decodes the second encoded subsequent frame data using the reconstructed no-show keyframe data as available reference frame data. In some implementations, a respective frame corresponding to the second encoded subsequent frame data may be reconstructed using previously reconstructed reference frame data, other than the reconstructed no-show- l-keyframe data and the reconstructed overlay frame data, as available reference frame data. The second reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data as available reference frame data. The decoder may include the second reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0111] The decoder may obtain second reconstructed subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining second reconstructed subsequent frame data (at 740) to obtaining second reconstructed subsequent frame data (at 740).

[0112] To obtain the reconstructed forward no-show keyframe data (at 750), the decoder extracts, reads, obtains, or otherwise accesses encoded forward no-show keyframe data (at 750) from the encoded bitstream. The encoded forward no-show keyframe data includes a bit, flag, or other syntax element, indicating that the encoded forward no-show keyframe data is for a keyframe. The encoded forward no-show keyframe data includes a bit, flag, or other syntax element, indicating that the encoded forward no-show keyframe data is for a no-show frame.

[0113] To obtain the reconstructed forward no-show keyframe data (at 750), the decoder decodes the encoded forward no-show keyframe data using intra prediction coding and reconstructs the reconstructed forward no-show keyframe data (a reconstructed forward no-show keyframe). The decoder obtains, from the encoded forward no-show keyframe data, the bit, flag, or other syntax element indicating that the reconstructed forward no-show keyframe is a keyframe. The decoder obtains, from the encoded forward no-show keyframe data, the bit, flag, or other syntax element indicating that the reconstructed forward no-show keyframe is a no-show frame (show_frame == 0. A forward no-show keyframe is other than a showable frame (showable_frame == 0). In some implementations, the decoder accesses from the encoded no-show keyframe data, the bit, flag, or other syntax element indicating an order hint value (order_hint) that is one greater than a most recently coded order hint value.

[0114] The decoder includes the reconstructed forward no-show keyframe data in the reference frame buffer for use as a reference frame for decoding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order.

[0115] In some implementations, the decoder accesses data indicating zero or more reference frames to refresh, or replace, with the reconstructed forward no-show keyframe data and the decoder replaces the indicated reference frames in the reference frame bufferwith the reconstructed forward no-show keyframe data, wherein the data indicating zero or more reference frames to refresh, or replace, includes one or more bits, flags, or other syntax elements,. For example, the one or more bits, flags, or other syntax elements indicating zero or more reference frames to refresh, or replace, with the reconstructed forward no-show keyframe data may include index values of the respective reference frames to refresh with respect to the reference frame buffer.

[0116] The decoder omits, avoids, or excludes outputting the reconstructed forward no-show keyframe for presentation or display.

[0117] To obtain the third reconstructed subsequent frame data (at 760), the decoder accesses third encoded subsequent frame data (at 760) from the encoded bitstream for one or more subsequent frames, such as subsequent to the encoded forward no-show keyframe data in the encoded bitstream. The third encoded subsequent frame data is encoded frame data for one or more frames. In some implementations, one or more of the frames are coded as intra prediction coded frames other than keyframes. In some implementations, one or more of the frames are coded as inter prediction coded frames coded using inter prediction using the reconstructed no-show keyframe data as available reference frame data. In some implementations, one or more of the frames are coded as inter prediction coded frames coded using inter prediction using reconstructed forward no-show keyframe data (the reconstructed forward no-show keyframe data) as available reference frame data.

[0118] To obtain the third reconstructed subsequent frame data (at 760), the decoder decodes the third encoded subsequent frame data using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data and the reconstructed forward no-show keyframe data as available reference frame data, a respective frame corresponding to the third encoded subsequent frame data may be reconstructed using other previously reconstructed reference frame data as available reference frame data.

[0119] The third reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data. The decoder may include the reconstructed frame data for one or more of the reconstructed frames of the third reconstructed subsequent frame data in the reference frame buffer.

[0120] Obtaining the third reconstructed subsequent frame data may include obtaining reconstructed subsequent frame data for one or more subsequent frames, as indicated by thebroken directional line from obtaining third reconstructed subsequent frame data (at 760) to obtaining third reconstructed subsequent frame data (at 760).

[0121] To obtain the reconstructed forward overlay frame data (at 770), the decoder accesses encoded forward overlay frame data (at 770) from the encoded bitstream, such as subsequent to accessing the third encoded subsequent frame data (at 760).

[0122] The decoder obtains, from the encoded forward overlay frame data, a bit, flag, or other syntax element indicating that reconstructing the forward overlay frame data includes outputting the corresponding reconstructed frame for display, which may be expressed as show_frame == 1.

[0123] To obtain the reconstructed forward overlay frame data (at 770), the decoder decodes the encoded forward overlay frame data using inter prediction coding using the reconstructed forward no-show keyframe data (obtained at 750) as available reference frame data and reconstructs the reconstructed forward overlay frame data (a reconstructed forward overlay frame). The decoder includes the reconstructed forward overlay frame data obtained by decoding the encoded forward overlay frame data in output data for presentation or display. In some implementations, the decoder accesses from the encoded forward no-show keyframe data, the bit, flag, or other syntax element indicating an order hint value (order_hint) of zero (order_hint == 0).

[0124] In some implementations, to obtain the reconstructed forward overlay frame data (at 770), the decoder determines whether the encoded forward overlay frame data is for an inter prediction coded frame. The decoder determines whether the order hint value is zero. The decoder determines whether a frame reconstructed prior, such as immediately prior, to reconstructing the encoded forward overlay frame data (a most recently reconstructed frame), is other than a keyframe.

[0125] In some implementations, in response to determining that the encoded forward overlay frame data is for an inter prediction coded frame, the order hint value is zero, and the frame reconstructed prior, such as immediately prior, to reconstructing the encoded forward overlay frame data, is other than a keyframe, the decoder accesses, from the encoded forward overlay frame data, a bit, flag, or other syntax element indicating a location, such as an index value with respect to the reference frame buffer, of the reconstructed forward no-show keyframe data (obtained at 750), for reconstructing the reconstructed forward overlay frame data (at 770). In some implementations, obtaining the reconstructed forward overlay frame data (at 770) includes refreshing the reference frame buffer, such that reference frame data,other than the reconstructed forward no-show keyframe data, is removed, deleted, omitted, or excluded from the reference frame buffer.

[0126] In some implementations, the decoder may omit, skip, avoid, or exclude including the reconstructed forward overlay frame data in the reference frame buffer.

[0127] To obtain the fourth reconstructed subsequent frame data (at 780), the decoder accesses fourth encoded subsequent frame data (at 780) from the encoded bitstream for one or more subsequent frames, such as subsequent to the encoded forward overlay frame data in the encoded bitstream. The fourth encoded subsequent frame data is encoded frame data for one or more frames respectively coded as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed forward no-show keyframe data (obtained at 750) as available reference frame data.

[0128] To obtain the fourth reconstructed subsequent frame data (at 780), the decoder decodes the fourth encoded subsequent frame data using the reconstructed forward no-show keyframe data (obtained at 750), as available reference frame data. In some implementations, in addition to using the reconstructed forward no-show keyframe data (obtained at 750) as available reference frame data, a respective frame corresponding to the fourth encoded subsequent frame data may be reconstructed using other previously reconstructed reference frame data, reconstructed subsequent to the reconstructed forward overlay frame, as available reference frame data.

[0129] The fourth reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed forward no-show keyframe data (obtained at 750) as available reference frame data. The decoder may include the reconstructed frame data for one or more of the reconstructed frames of the fourth reconstructed subsequent frame data in the reference frame buffer.

[0130] Obtaining the fourth reconstructed subsequent frame data may include obtaining reconstructed subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining fourth reconstructed subsequent frame data (at 780) to obtaining fourth reconstructed subsequent frame data (at 780).

[0131] In an example, decoding using no-show filtered keyframes 700 may include obtaining encoded forward no-show keyframe data from an encoded bitstream. The encoded forward no-show keyframe data may include data indicating that the encoded forward no-show keyframe data is for a keyframe, data indicating that the encoded forward no-show keyframe data is for a no-show frame, and data indicating zero or more reference frames from the reference frame buffer to refresh. In the example, decoding using no-show filteredkeyframes 700 may include obtaining reconstructed forward no-show keyframe data by decoding the encoded forward no-show keyframe data using intra prediction, refreshing the zero or more reference frames from the reference frame buffer with the reconstructed forward no-show keyframe data, subsequent to decoding the encoded forward no-show keyframe data, obtaining encoded subsequent frame data from the encoded bitstream, obtaining reconstructed subsequent frame data by decoding the encoded subsequent frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data, subsequent to obtaining the encoded subsequent frame data, obtaining encoded forward overlay frame data from the encoded bitstream, obtaining reconstructed forward overlay frame data by decoding the encoded forward overlay frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data, including the reconstructed forward overlay frame data in output data for display, excluding the reconstructed forward no-show keyframe data from the output data, and outputting the output data.

[0132] In an example, decoding using no-show filtered keyframes 700 may include decoding an encoded bitstream. The encoded bitstream may include encoded forward no-show keyframe data. The encoded forward no-show keyframe data may include data indicating that the encoded forward no-show keyframe data is for a keyframe, data indicating that the encoded forward no-show keyframe data is for a no-show frame, and data indicating zero or more reference frames from the reference frame buffer to refresh. The encoded bitstream may include, subsequent to the encoded forward no-show keyframe data, encoded subsequent frame data for obtaining reconstructed subsequent frame data by decoding the encoded subsequent frame data using inter prediction using reconstructed forward no-show keyframe data corresponding to the encoded forward no-show keyframe data as available reference frame data. The encoded bitstream may include, subsequent to the encoded subsequent frame data, encoded forward overlay frame data for obtaining reconstructed forward overlay frame data by decoding the encoded forward overlay frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data.

[0133] In an example, an apparatus may implement decoding using no-show filtered keyframes. The apparatus may include a non-transitory computer readable medium, and a processor configured to execute instructions stored on the non-transitory computer readable medium to obtain encoded forward no-show keyframe data from an encoded bitstream. The encoded forward no-show keyframe data may include data indicating that the encodedforward no-show keyframe data is for a keyframe, data indicating that the encoded forward no-show keyframe data is for a no-show frame, and data indicating zero or more reference frames from the reference frame buffer to refresh. In the example, the processor may execute the instruction to obtain reconstructed forward no-show keyframe data. To obtain the reconstructed forward no-show keyframe data, the processor may execute the instructions to decode the encoded forward no-show keyframe data using intra prediction. The processor may execute the instruction to refresh the zero or more reference frames from the reference frame buffer with the reconstructed forward no-show keyframe data. The processor may execute the instruction to, subsequent to the encoded forward no-show keyframe data, obtain encoded subsequent frame data from the encoded bitstream. The processor may execute the instruction to obtain reconstructed subsequent frame data. To obtain the reconstructed subsequent frame data, the processor may execute the instruction to decode the encoded subsequent frame data by inter prediction in accordance with the reconstructed forward no-show keyframe data as available reference frame data. The processor may execute the instruction to, subsequent to the encoded subsequent frame data, obtain encoded forward overlay frame data from the encoded bitstream. The processor may execute the instruction to obtain reconstructed forward overlay frame data. To obtain the reconstructed forward overlay frame data, the processor may execute the instruction to decoding the encoded forward overlay frame data by inter prediction in accordance with the reconstructed forward no-show keyframe data as available reference frame data. The processor may execute the instruction to include the reconstructed forward overlay frame data in output data for display. The processor may execute the instruction to exclude the reconstructed forward no-show keyframe data from the output data. The processor may execute the instruction to output the output data.

[0134] FIG. 8 is a flowchart diagram of an example of encoding using no-show keyframes 800 in accordance with implementations of this disclosure. Encoding using no-show keyframes 800 may be implemented in an encoder, such as the encoder 400 shown in FIG. 4, or one or more portions thereof.

[0135] Encoding using no-show keyframes 800 includes encoding an input video steam, such as the input video stream 402 shown in FIG. 4, or one or more portions thereof, to generate an encoded (compressed) output bitstream, such as the encoded (compressed) bitstream 404 shown in FIG. 4, or one or more portions thereof. In block-based hybrid video coding, to reduce, or minimize, the resource utilization, such as bandwidth utilization, for signaling, storing, or both, compressed, or encoded, video data, redundant data, such as spatially redundant data, temporally redundant data, or both, is omitted or excluded from thecompressed, or encoded, data. For example, spatial redundancy may be reduced using intra prediction, wherein a block of a frame is predicted from previously reconstructed data for the frame. In another example, temporal redundancy may be reduced using inter prediction, wherein the current block is predicted from one or more reference frames, which may be previously reconstructed frames, constructed reference frames, or both.

[0136] Encoding using no-show keyframes 800 includes obtaining encoded no-show keyframe data (at 810), obtaining first encoded subsequent frame data (at 820), obtaining encoded overlay frame data (at 830), obtaining second encoded subsequent frame data (at 840), obtaining encoded forward no-show keyframe data (at 850), obtaining third encoded subsequent frame data (at 860), obtaining encoded forward overlay frame data (at 870), and obtaining fourth encoded subsequent frame data (at 880). Encoding using no-show keyframes 800 may include aspects not expressly shown in FIG. 8 for simplicity, such as filtering, such as the filtering shown (at 480) in FIG. 4.

[0137] Although FIG. 8 shows obtaining encoded no-show keyframe data (at 810), obtaining first encoded subsequent frame data (at 820), obtaining encoded overlay frame data (at 830), obtaining second encoded subsequent frame data (at 840), obtaining encoded forward no-show keyframe data (at 850), obtaining third encoded subsequent frame data (at 860), obtaining encoded forward overlay frame data (at 870), and obtaining fourth encoded subsequent frame data (at 880), obtaining encoded no-show keyframe data (at 810), obtaining first encoded subsequent frame data (at 820), obtaining encoded overlay frame data (at 830), obtaining second encoded subsequent frame data (at 840), may be performed in the absence of obtaining encoded forward no-show keyframe data (at 850), obtaining third encoded subsequent frame data (at 860), obtaining encoded forward overlay frame data (at 870), and obtaining fourth encoded subsequent frame data (at 880).

[0138] Although FIG. 8 shows obtaining encoded no-show keyframe data (at 810), obtaining first encoded subsequent frame data (at 820), obtaining encoded overlay frame data (at 830), obtaining second encoded subsequent frame data (at 840), obtaining encoded forward no-show keyframe data (at 850), obtaining third encoded subsequent frame data (at 860), obtaining encoded forward overlay frame data (at 870), and obtaining fourth encoded subsequent frame data (at 880), obtaining encoded no-show keyframe data (at 810), obtaining first encoded subsequent frame data (at 820), obtaining encoded overlay frame data (at 830), may be omitted, skipped, avoided, or excluded.

[0139] To obtain the encoded no-show keyframe data (at 810) the encoder obtains a first input frame (at 810) from the input video stream. Encoding the first input frame includesencoding the first input frame as a keyframe (key frame or key_frame), an inter prediction coded frame (inter_frame), an intra prediction coded frame (intra_only_frame) other than a keyframe, or a switch frame (switch_frame). The encoder determines to encode the first input frame as a no-show keyframe (at 810).

[0140] To obtain the encoded no-show keyframe data (at 810) the encoder obtains no-show keyframe data (at 810) by processing the first input frame. In some implementations, the encoder filters, such as using temporal filtering, the first input frame, such as to remove, or reduce, noise, such as input noise, to obtain the no-show keyframe data. Other processing may be used to obtain the no-show keyframe data.

[0141] To obtain the encoded no-show keyframe data (at 810) the encoder encodes the no-show keyframe data (at 810) using intra prediction coding.

[0142] The encoder includes the encoded no-show keyframe data in the encoded bitstream.

[0143] The encoder includes, such as in the encoded no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating that the no-show keyframe is a keyframe.

[0144] The encoder includes, such as in the encoded no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating that the no-show keyframe is a no-show frame (show_frame == 0. A no-show frame is other than a showable frame (showable_frame == 0).

[0145] In some implementations, the encoder includes, such as in the encoded no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating an order hint value (order_hint) of zero (order_hint == 0) for the no-show keyframe.

[0146] The encoder decodes the encoded no-show keyframe data using intra prediction coding to obtain decoded no-show keyframe data and reconstructs the decoded no-show keyframe data to obtain reconstructed no-show keyframe data (a reconstructed no-show keyframe).

[0147] The encoder includes the reconstructed no-show keyframe data in a reference frame buffer for use as a reference frame for coding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order. In some implementations, the encoder removes, deletes, omits, or excludes reference frames, other than the reconstructed frame corresponding to a no-show keyframe, from the reference frame buffer.

[0148] To obtain the first encoded subsequent frame data (at 820) the encoder obtains first subsequent input frame data (at 820) from the input video stream.

[0149] To obtain the first encoded subsequent frame data (at 820) the encoder encodes the first subsequent input frame data (at 820), on a per-frame basis, as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed no-show keyframe data as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data as available reference frame data, a respective frame from the first subsequent input frame data may be encoded using other previously reconstructed reference frame data as available reference frame data. Encoding the subsequent frames using the reconstructed no-show keyframe data as available reference frame data improves coding efficiency, accuracy, or both, relative to encoding the subsequent frames using reconstructed keyframe data (unfiltered) as available reference frame data.

[0150] The encoder includes first encoded subsequent frame data in the encoded bitstream, such as subsequent to the encoded no-show keyframe data.

[0151] The encoder includes, in the first encoded subsequent frame data, on a per-frame basis, a bit, flag, or other syntax element indicating that reconstructing the respective frame omits, excludes, or avoids outputting the frame for display, which may be expressed as show_frame == 0.

[0152] The encoder obtains first reconstructed subsequent frame data (at 820). To obtain the first reconstructed subsequent frame data (at 820), the encoder decodes the first encoded subsequent frame data using the reconstructed no-show keyframe data as available reference frame data. The first reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data as available reference frame data. The encoder may include the reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0153] Obtaining the first encoded subsequent frame data may include obtaining encoded subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining first encoded subsequent frame data (at 820) to obtaining first encoded subsequent frame data (at 820).

[0154] To obtain the encoded overlay frame data (at 830) the encoder encodes the first input frame, previously used to obtain the no-show keyframe, by inter prediction coding using the reconstructed no-show keyframe data as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data as availablereference frame data, the encoded overlay frame data may be obtained by encoding the first input frame using other previously reconstructed reference frame data as available reference frame data.

[0155] The encoder includes the encoded overlay frame data in the encoded bitstream, such as subsequent to the encoded no-show keyframe data and the first encoded subsequent frame data.

[0156] In some implementations, the encoded overlay frame data corresponds to a key frame dependent recovery point (overlay frame), wherein the encoder includes, in the encoded bitstream, such as in the encoded overlay frame data, a bit, flag, or other syntax element, indicating that outputting, for presentation or display, in accordance with decoding the encoded overlay frame data, a frame other than the overlay frame is omitted (show_existing_frame == 0).

[0157] The encoder includes, in the encoded bitstream, such as in the encoded overlay frame data, a bit, flag, or other syntax element indicating that reconstructing the encoded overlay frame data includes outputting the corresponding reconstructed frame for display, which may be expressed as show_frame == 1.

[0158] In some implementations, the encoder includes, in the encoded bitstream, such as in the encoded overlay frame data, a bit, flag, or other syntax element indicating an order hint value (order_hint) of zero (order_hint == 0).

[0159] The encoder obtains decoded overlay frame data by decoding the encoded overlay frame data using inter prediction coding using the reconstructed no-show keyframe data as available reference frame data and obtains reconstructed overlay frame data by reconstructing the decoded overlay frame data (a reconstructed overlay frame).

[0160] In some implementations, the encoder may omit, skip, avoid, or exclude including the reconstructed overlay frame data in the reference frame buffer.

[0161] Although not expressly shown in FIG. 8, subsequent to encoding the overlay frame data, the encoder may include, in the encoded bitstream, encoded frame data that omits, or excludes, encoded image data and includes data, such as a bit, flag, or other syntax element that indicates the output, presentation, or display of a previously reconstructed frame obtained by decoding the first encoded subsequent frame data, which may be expressed as show_existing_frame == 1, wherein the encoded frame data includes data, such as a defined number, count, or cardinality of bits, such as three bits, (frame_to_show_map_idx) indicating an index value of a frame from the reference frame buffer to be shown.

[0162] To obtain the second encoded subsequent frame data (at 840) the encoder obtains second subsequent input frame data (at 840) from the input video stream.

[0163] To obtain the second encoded subsequent frame data (at 840) the encoder encodes second encoded subsequent frame data (at 840), on a per-frame basis, as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed no-show keyframe data as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data as available reference frame data, a respective frame from the second subsequent input frame data may be encoded using other previously reconstructed reference frame data as available reference frame data. Encoding the subsequent frames using the reconstructed no-show keyframe data as available reference frame data improves coding efficiency, accuracy, or both, relative to encoding the subsequent frames using reconstructed keyframe data (unfiltered) as available reference frame data.

[0164] The encoder includes the second encoded subsequent frame data in the encoded bitstream, such as subsequent to the encoded overlay frame data.

[0165] The encoder obtains second reconstructed subsequent frame data (at 840). To obtain the second reconstructed subsequent frame data (at 840), the encoder decodes the second encoded subsequent frame data using the reconstructed no-show keyframe data as available reference frame data. The second reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data as available reference frame data. The encoder may include the reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0166] Obtaining the second encoded subsequent frame data may include obtaining encoded subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining second encoded subsequent frame data (at 840) to obtaining second encoded subsequent frame data (at 840).

[0167] To obtain the encoded forward no-show keyframe data (at 850) the encoder obtains a second input frame (at 850) from the input video stream. Encoding the second input frame includes encoding the second input frame as a keyframe (key frame or key_frame), an inter prediction coded frame (inter_frame), an intra prediction coded frame (intra_only_frame) other than a keyframe, or a switch frame (switch_frame). The encoder determines to encode the second input frame as a forward no-show keyframe (at 850).

[0168] To obtain the encoded forward no-show keyframe data (at 850) the encoder obtains forward no-show keyframe data (at 850) by processing the second input frame. In some implementations, the encoder filters, such as using temporal filtering, the second input frame, such as to remove, or reduce, noise, such as input noise, to obtain the forward no-show keyframe data. Other processing may be used to obtain the forward no-show keyframe data.

[0169] To obtain the encoded forward no-show keyframe data (at 850) the encoder encodes the forward no-show keyframe data (at 850) using intra prediction coding.

[0170] The encoder includes the encoded forward no-show keyframe data in the encoded bitstream.

[0171] The encoder includes, such as in the encoded forward no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating that the forward no-show keyframe is a keyframe.

[0172] The encoder includes, such as in the encoded forward no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating that the forward no-show keyframe is a no-show frame (show_frame == 0. A forward no-show keyframe is other than a showable frame (showable_frame == 0).

[0173] In some implementations, the encoder includes, such as in the encoded forward no-show keyframe data, a bit, flag, or other syntax element, in the encoded bitstream indicating an order hint value (order_hint) for the forward no-show keyframe that is one greater than a most recently coded order hint value.

[0174] The encoder decodes the encoded forward no-show keyframe data using intra prediction coding (at 850) to obtain decoded forward no-show keyframe data and reconstructs the decoded forward no-show keyframe data to obtain reconstructed forward no-show keyframe data (a reconstructed forward no-show keyframe) (at 850).

[0175] The encoder includes the reconstructed forward no-show keyframe data in the reference frame buffer for use as a reference frame for coding, subsequent to the keyframe in coding order, one or more frames that are subsequent to the keyframe in temporal, display, or input order.

[0176] In some implementations, the encoder includes, such as in the encoded forward no-show keyframe data, one or more bits, flags, or other syntax elements indicating zero or more reference frames to refresh, or replace, with the reconstructed forward no-show keyframe data. In some implementations, the encoder replaces the indicated reference frames in the reference frame buffer with the reconstructed forward no-show keyframe data.

[0177] To obtain the third encoded subsequent frame data (at 860) the encoder obtains third subsequent input frame data (at 860) from the input video stream.

[0178] To obtain the third encoded subsequent frame data (at 860) the encoder encodes the third subsequent input frame data (at 860), on a per-frame basis, as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data. In some implementations, in addition to using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data, a respective frame from the third subsequent input frame data may be encoded using other previously reconstructed reference frame data as available reference frame data. Encoding the subsequent frames using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data improves coding efficiency, accuracy, or both, relative to encoding the subsequent frames using reconstructed keyframe data (unfiltered) as available reference frame data.

[0179] The encoder includes third encoded subsequent frame data in the encoded bitstream (at 860), such as subsequent to the encoded forward no-show keyframe data.

[0180] The encoder obtains third reconstructed subsequent frame data (at 860). To obtain the third reconstructed subsequent frame data (at 860), the encoder decodes the third encoded subsequent frame data using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data. The third reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed no-show keyframe data, the reconstructed forward no-show keyframe data, or both, as available reference frame data. The encoder may include the reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0181] Obtaining the third encoded subsequent frame data may include obtaining encoded subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining third encoded subsequent frame data (at 860) to obtaining third encoded subsequent frame data (at 860).

[0182] To obtain the encoded forward overlay frame data (at 870) the encoder encodes the second input frame, previously used to obtain the forward no-show keyframe (at 850), by inter prediction coding using the reconstructed forward no-show keyframe data as available reference frame data.

[0183] The encoder includes the encoded forward overlay frame data in the encoded bitstream (at 870), such as subsequent to the third encoded subsequent frame data.

[0184] In some implementations, the encoder includes, in the encoded bitstream, such as in the encoded forward overlay frame data, a bit, flag, or other syntax element indicating that reconstructing the encoded forward overlay frame data includes outputting the corresponding reconstructed frame (forward overlay frame) for display, which may be expressed as show_frame == 1.

[0185] In some implementations, the encoder includes, such as in the encoded forward overlay frame data, a bit, flag, or other syntax element, in the encoded bitstream indicating an order hint value (order_hint) of zero (order_hint == 0) for the no-show keyframe.

[0186] The encoder obtains decoded forward overlay frame data by decoding the encoded forward overlay frame data using inter prediction coding using the reconstructed forward no-show keyframe data as available reference frame data and obtains reconstructed forward overlay frame data by reconstructing the decoded forward overlay frame data (a reconstructed forward overlay frame).

[0187] In some implementations, the encoder may omit, skip, avoid, or exclude including the reconstructed forward overlay frame data in the reference frame buffer.

[0188] In some implementations, to obtain the reconstructed forward overlay frame data (at 870), the encoder determines whether the encoded forward overlay frame data is for an inter prediction coded frame. The encoder determines whether the order hint value is zero. The encoder determines whether a frame reconstructed prior, such as immediately prior, to reconstructing the encoded forward overlay frame data, is other than a keyframe.

[0189] In some implementations, in response to determining that the encoded forward overlay frame data is for an inter prediction coded frame, the order hint value is zero, and the frame reconstructed prior, such as immediately prior, to reconstructing the encoded forward overlay frame data, is other than a keyframe, the encoder includes, such as in the encoded forward overlay frame data, a bit, flag, or other syntax element, in the encoded bitstream a bit, flag, or other syntax element indicating a location, such as an index value with respect to the reference frame buffer, of the reconstructed forward no-show keyframe data (obtained at 850), for reconstructing the reconstructed forward overlay frame data (at 870). In some implementations, obtaining the reconstructed forward overlay frame data (at 870) includes refreshing the reference frame buffer, such that reference frame data, other than the reconstructed forward no-show keyframe data, is removed, deleted, omitted, or excluded from the reference frame buffer.

[0190] To obtain the fourth encoded subsequent frame data (at 880) the encoder obtains fourth subsequent input frame data (at 880) from the input video stream.

[0191] To obtain the fourth encoded subsequent frame data (at 880) the encoder encodes the fourth subsequent input frame data (at 880), on a per-frame basis, as intra prediction coded frames other than keyframes or as inter prediction coded frames coded using the reconstructed forward no-show keyframe data as available reference frame data. Encoding the subsequent frames using the reconstructed forward no-show keyframe data as available reference frame data improves coding efficiency, accuracy, or both, relative to encoding the subsequent frames using reconstructed keyframe data (unfiltered) as available reference frame data. In some implementations, in addition to using the reconstructed forward no-show keyframe data (obtained at 850) as available reference frame data, a respective frame corresponding to the fourth encoded subsequent frame data may be reconstructed using other previously reconstructed reference frame data, reconstructed subsequent to the reconstructed forward overlay frame, as available reference frame data.

[0192] The encoder includes the fourth encoded subsequent frame data in the encoded bitstream (at 880), such as subsequent to the encoded forward overlay frame data.

[0193] The encoder obtains fourth reconstructed subsequent frame data (at 880). To obtain the fourth reconstructed subsequent frame data (at 880), the encoder decodes the fourth encoded subsequent frame data using the reconstructed forward no-show keyframe data as available reference frame data. The fourth reconstructed subsequent frame data is reconstructed frame data for one or more frames reconstructed using the reconstructed forward no-show keyframe data as available reference frame data. The encoder may include the reconstructed frame data for one or more of the reconstructed frames in the reference frame buffer.

[0194] Obtaining the fourth encoded subsequent frame data may include obtaining encoded subsequent frame data for one or more subsequent frames, as indicated by the broken directional line from obtaining fourth encoded subsequent frame data (at 880) to obtaining fourth encoded subsequent frame data (at 880).

[0195] Although not expressly shown in FIG. 8, the encoder may output the encoded bitstream for storage, to a decoder, or both.

[0196] In an example, encoding using no-show filtered keyframes 800 includes generating an encoded bitstream by encoding an input video stream. Generating the encoded bitstream includes obtaining a first input frame from the input video stream, generating forward no-show keyframe data by filtering the first input frame, and generating encodedforward no-show keyframe data by intra prediction coding the forward no-show keyframe data. Generating the encoded forward no-show keyframe data comprises including, in the encoded forward no-show keyframe data, data indicating that the encoded forward no-show keyframe data is for a keyframe, data indicating that the encoded forward no-show keyframe data is for a no-show frame, and data indicating zero or more reference frames from a reference frame buffer to refresh. Generating the encoded forward no-show keyframe data comprises including the encoded forward no-show keyframe data in the encoded bitstream, generating reconstructed forward no-show keyframe data by decoding the encoded forward no-show keyframe data, obtaining a second input frame from the input video stream, the second input frame sequentially after the first input frame in the input video stream, generating encoded frame data by inter prediction coding the second input frame using the reconstructed forward no-show keyframe data as available reference frame data, including the encoded frame data in the encoded bitstream subsequent to the encoded forward no-show keyframe data, and generating encoded forward overlay frame data by inter prediction coding the first input frame using the reconstructed forward no-show keyframe data as available reference frame data. Generating the encoded forward overlay frame data comprises including, in the encoded forward overlay frame data, data indicating that the encoded forward overlay frame data is for an inter prediction coded frame, data indicating that reconstructing the encoded forward overlay frame data includes outputting, for display, a reconstructed frame generated by reconstructing the encoded forward overlay frame data, and data indicating an order hint value of zero. Generating the encoded forward no-show keyframe data comprises, in response to generating the encoded forward overlay frame data, refreshing the reference frame buffer using the reconstructed forward no-show keyframe data, including the encoded forward overlay frame data in the encoded bitstream subsequent to the encoded frame data, and outputting the encoded bitstream.

[0197] In an example, an apparatus may implement encoding using no-show filtered keyframes. The apparatus may include a non-transitory computer readable medium, and a processor configured to execute instructions stored on the non-transitory computer readable medium to obtain a first input frame from the input video stream, generate forward no-show keyframe data, wherein, to generate the forward no-show keyframe data, the processor is configured to execute the instructions to filter the first input frame. The processor is configured to execute the instructions to generate encoded forward no-show keyframe data, wherein, to generate the encoded forward no-show keyframe data, the processor is configured to execute the instructions to intra prediction code the forward no-show keyframe data. Togenerate the encoded forward no-show keyframe data, the processor is configured to execute the instructions to include, in the encoded forward no-show keyframe data, data that indicates that the encoded forward no-show keyframe data is for a keyframe, data that indicates that the encoded forward no-show keyframe data is for a no-show frame, and data that indicates zero or more reference frames from a reference frame buffer to refresh. The processor is configured to execute the instructions to include the encoded forward no-show keyframe data in the encoded bitstream and generate reconstructed forward no-show keyframe data, wherein, to generate the reconstructed forward no-show keyframe data, the processor is configured to execute the instructions to decode the encoded forward no-show keyframe data. The processor is configured to execute the instructions to obtain a second input frame from the input video stream, the second input frame sequentially after the first input frame in the input video stream. The processor is configured to execute the instructions to generate encoded frame data, wherein, to generate the encoded frame data, the processor is configured to execute the instructions to inter prediction code the second input frame in accordance with the reconstructed forward no-show keyframe data as available reference frame data. The processor is configured to execute the instructions to include the encoded frame data in the encoded bitstream subsequent to the encoded forward no-show keyframe data, and generate encoded forward overlay frame data, wherein, to generate the encoded forward overlay frame data, the processor is configured to execute the instructions to inter prediction code the first input frame in accordance with the reconstructed forward no-show keyframe data as available reference frame data. To generate the encoded forward overlay frame data, the processor is configured to execute the instructions to include, in the encoded forward overlay frame data, data that indicates that that the encoded forward overlay frame data is for an inter prediction coded frame, data that indicates that reconstruct the encoded forward overlay frame data includes outputting, for display, a reconstructed frame generated by reconstruct the encoded forward overlay frame data, and data that indicates an order hint value of zero. To generate the encoded forward no-show keyframe data, the processor is configured to execute the instructions to, in response to the encoded forward overlay frame data, refresh the reference frame buffer in accordance with the reconstructed forward no-show keyframe data. The processor is configured to execute the instructions to include the encoded forward overlay frame data in the encoded bitstream subsequent to the encoded frame data and output the encoded bitstream.

[0198] As used herein, the terms “optimal”, “optimized”, “optimization”, or other forms thereof, are relative to a respective context and are not indicative of absolute theoretic optimization unless expressly specified herein.

[0199] As used herein, the term “set” indicates a distinguishable collection or grouping of zero or more distinct elements or members that may be represented as a one-dimensional array or vector, except as expressly described herein or otherwise clear from context.

[0200] The words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “example” or “exemplary” not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Moreover, use of the term “an embodiment” or “one embodiment” or “an implementation” or “one implementation” throughout is not intended to mean the same embodiment or implementation unless described as such. As used herein, the terms “determine” and “identify”, or any variations thereof, includes selecting, ascertaining, computing, looking up, receiving, determining, establishing, obtaining, or otherwise identifying or determining in any manner whatsoever using one or more of the devices shown in FIG. 1.

[0201] Further, for simplicity of explanation, although the figures and descriptions herein may include sequences or series of steps or stages, elements of the methods disclosed herein can occur in various orders and / or concurrently. Additionally, elements of the methods disclosed herein may occur with other elements not explicitly presented and described herein. Furthermore, one or more elements of the methods described herein may be omitted, avoided, or excluded from implementations of methods in accordance with the disclosed subject matter.

[0202] The implementations of the transmitting computing and communication device 100A and / or the receiving computing and communication device 100B (and the algorithms, methods, instructions, etc. stored thereon and / or executed thereby) can be realized inhardware, software, or any combination thereof. The hardware can include, for example, computers, intellectual property (IP) cores, application- specific integrated circuits (ASICs), programmable logic arrays, optical processors, programmable logic controllers, microcode, microcontrollers, servers, microprocessors, digital signal processors or any other suitable circuit. In the claims, the term “processor” should be understood as encompassing any of the foregoing hardware, either singly or in combination. The terms “signal” and “data” are used interchangeably. Further, portions of the transmitting computing and communication device 100A and the receiving computing and communication device 100B do not necessarily have to be implemented in the same manner.

[0203] Further, in one implementation, for example, the transmitting computing and communication device 100A or the receiving computing and communication device 100B can be implemented using a computer program that, when executed, carries out any of the respective methods, algorithms and / or instructions described herein. In addition, or alternatively, for example, a special purpose computer / processor can be utilized which can contain specialized hardware for carrying out any of the methods, algorithms, or instructions described herein.

[0204] The transmitting computing and communication device 100A and receiving computing and communication device 100B can, for example, be implemented on computers in a real-time video system. Alternatively, the transmitting computing and communication device 100A can be implemented on a server and the receiving computing and communication device 100B can be implemented on a device separate from the server, such as a hand-held communications device. In this instance, the transmitting computing and communication device 100A can encode content using an encoder 400 into an encoded video signal and transmit the encoded video signal to the communications device. In turn, the communications device can then decode the encoded video signal using a decoder 500. Alternatively, the communications device can decode content stored locally on the communications device, for example, content that was not transmitted by the transmitting computing and communication device 100A. Other suitable transmitting computing and communication device 100A and receiving computing and communication device 100B implementation schemes are available. For example, the receiving computing and communication device 100B can be a generally stationary personal computer rather than a portable communications device and / or a device including an encoder 400 may also include a decoder 500.

[0205] Further, all or a portion of implementations can take the form of a computer program product accessible from, for example, a tangible computer-usable or computer-readable medium. A computer-usable or computer-readable medium can be any device that can, for example, tangibly contain, store, communicate, or transport the program for use by or in connection with any processor. The medium can be, for example, an electronic, magnetic, optical, electromagnetic, or a semiconductor device. Other suitable mediums are also available.

[0206] It will be appreciated that aspects can be implemented in any convenient form. For example, aspects may be implemented by appropriate computer programs which may be carried on appropriate carrier media which may be tangible carrier media (e.g. disks) or intangible carrier media (e.g. communications signals). Aspects may also be implemented using suitable apparatus which may take the form of programmable computers running computer programs arranged to implement the methods and / or techniques disclosed herein. Aspects can be combined such that features described in the context of one aspect may be implemented in another aspect.

[0207] The above-described implementations have been described in order to allow easy understanding of the application are not limiting. On the contrary, the application covers various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structure as is permitted under the law.

Claims

CLAIMSWhat is claimed is:

1. A method comprising:obtaining encoded no-show keyframe data from an encoded bitstream, wherein the encoded no-show keyframe data includes:data indicating that the encoded no-show keyframe data is for a keyframe; and data indicating that the encoded no-show keyframe data is for a no-show frame;obtaining reconstructed no-show keyframe data by decoding the encoded no-show keyframe data using intra prediction;subsequent to obtaining the encoded no-show keyframe data, obtaining encoded overlay frame data from the encoded bitstream;subsequent to obtaining the reconstructed no-show keyframe data, obtaining reconstructed overlay frame data by decoding the encoded overlay frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data;including the reconstructed overlay frame data in output data for display; excluding the reconstructed no-show keyframe data from the output data; and outputting the output data.

2. The method of claim 1, further comprising:in response to obtaining the reconstructed no-show keyframe data refreshing a reference frame buffer by:including the reconstructed no-show keyframe data in the reference frame buffer; andexcluding reference frame data other than the reconstructed no-show keyframe data from the reference frame buffer.

3. The method of claim 2, further comprising:omitting refreshing the reference frame buffer in response to obtaining the reconstructed overlay frame data.

4. The method of claim 2, wherein the encoded overlay frame data includes data indicating the output of the reconstructed overlay frame data in response to decoding the encoded overlay frame data.

5. The method of claim 2, further comprising:subsequent to obtaining the encoded no-show keyframe data, obtaining encoded subsequent frame data from the encoded bitstream;obtaining reconstructed subsequent frame data by decoding the encoded subsequent frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data; andincluding the reconstructed subsequent frame data in the output data for display subsequent to the reconstructed overlay frame data.

6. The method of claim 5, wherein obtaining the encoded subsequent frame data includes obtaining the encoded subsequent frame data subsequent to obtaining the encoded overlay frame data.

7. The method of claim 6, further comprising:subsequent to obtaining the encoded subsequent frame data, obtaining encoded forward no-show keyframe data from the encoded bitstream, wherein the encoded forward no-show keyframe data includes:data indicating that the encoded forward no-show keyframe data is for a keyframe;data indicating that the encoded forward no-show keyframe data is for a no- show frame; anddata indicating zero or more reference frames from the reference frame buffer to refresh;obtaining reconstructed forward no-show keyframe data by decoding the encoded forward no-show keyframe data using intra prediction;refreshing the zero or more reference frames from the reference frame buffer with the reconstructed forward no-show keyframe data;subsequent to decoding the encoded forward no-show keyframe data, obtaining second encoded subsequent frame data from the encoded bitstream;obtaining second reconstructed subsequent frame data by decoding the second encoded subsequent frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data;subsequent to obtaining the second encoded subsequent frame data, obtaining encoded forward overlay frame data from the encoded bitstream;obtaining reconstructed forward overlay frame data by decoding the encoded forward overlay frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data;including the reconstructed forward overlay frame data in the output data for display; andexcluding the reconstructed forward no-show keyframe data from the output data.

8. The method of claim 7, wherein obtaining the reconstructed forward overlay frame data includes:obtaining the reconstructed forward overlay frame data in response to:determining that the encoded forward overlay frame data indicates that the encoded forward overlay frame data is for an inter prediction coded frame;determining that the encoded forward overlay frame data includes data indicating an order hint value of zero; anddetermining that a most recently reconstructed frame is other than a keyframe; refreshing the reference frame buffer by:including the reconstructed forward no-show keyframe data in the reference frame buffer; andexcluding reference frame data other than the reconstructed forward no-show keyframe data from the reference frame buffer;accessing, from the encoded forward overlay frame data, an index value of the reconstructed forward no-show keyframe data in the reference frame buffer; and obtaining the forward no-show keyframe data from the reference frame buffer.

9. An apparatus for use in decoding using no-show keyframes, the apparatus comprising:a non-transitory computer readable medium; anda processor configured to execute instructions stored on the non-transitory computer readable medium to:obtain encoded no-show keyframe data from an encoded bitstream, wherein the encoded no-show keyframe data includes:data indicating that the encoded no-show keyframe data is for a keyframe; anddata indicating that the encoded no-show keyframe data is for a no- show frame;obtain reconstructed no-show keyframe data wherein, to obtain the reconstructed no-show keyframe data, the processor executes the instructions to decode the encoded no-show keyframe data using intra prediction;obtain, subsequent to the encoded no-show keyframe data, encoded overlay frame data from the encoded bitstream;obtain reconstructed overlay frame data wherein, to obtain the reconstructed overlay frame data, the processor executes the instructions to decode the encoded overlay frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data;include the reconstructed overlay frame data in output data for display; exclude the reconstructed no-show keyframe data from the output data; and output the output data.

10. The apparatus of claim 9, wherein the processor is configured to execute the instructions to:in response to the reconstructed no-show keyframe data, refresh a reference frame buffer, wherein, to refresh the reference frame buffer, the processor executes the instructions to:include the reconstructed no-show keyframe data in the reference frame buffer; andexclude reference frame data other than the reconstructed no-show keyframe data from the reference frame buffer.

11. The apparatus of claim 10, wherein the processor is configured to execute the instructions to:omit refreshing the reference frame buffer in response to the reconstructed overlay frame data.

12. The apparatus of claim 10, wherein the encoded overlay frame data includes data indicating the output of the reconstructed overlay frame data in response to decoding the encoded overlay frame data.

13. The apparatus of claim 10, wherein the processor is configured to execute the instructions to:subsequent to the encoded no-show keyframe data, obtain encoded subsequent frame data from the encoded bitstream;obtain reconstructed subsequent frame data, wherein, to obtain the reconstructed subsequent frame data, the processor executes the instructions to decode the encoded subsequent frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data; andinclude the reconstructed subsequent frame data in the output data for display subsequent to the reconstructed overlay frame data.

14. The apparatus of claim 13, wherein, to obtain the encoded subsequent frame data, the processor executes the instructions to obtain the encoded subsequent frame data subsequent to the encoded overlay frame data.

15. The apparatus of claim 14, , wherein the processor is configured to execute the instructions to:subsequent to the encoded subsequent frame data, obtain encoded forward no-show keyframe data from the encoded bitstream, wherein the encoded forward no-show keyframe data includes:data indicating that the encoded forward no-show keyframe data is for a keyframe;data indicating that the encoded forward no-show keyframe data is for a no- show frame; anddata indicating zero or more reference frames from the reference frame buffer to refresh;obtain reconstructed forward no-show keyframe data, wherein, to obtain the reconstructed forward no-show keyframe data, the processor executes the instruction to decode the encoded forward no-show keyframe data using intra prediction;refresh the zero or more reference frames from the reference frame buffer with the reconstructed forward no-show keyframe data;subsequent to the encoded forward no-show keyframe data, obtain second encoded subsequent frame data from the encoded bitstream;obtain second reconstructed subsequent frame data, wherein, to obtain the second reconstructed subsequent frame data, the processor executes the instruction to decode the second encoded subsequent frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data;subsequent to the second encoded subsequent frame data, obtain encoded forward overlay frame data from the encoded bitstream;obtain reconstructed forward overlay frame data, wherein, to obtain the reconstructed forward overlay frame data, the processor executes the instruction to decode the encoded forward overlay frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data;include the reconstructed forward overlay frame data in the output data for display; andexclude the reconstructed forward no-show keyframe data from the output data.

16. The apparatus of claim 15, wherein, to obtain the reconstructed forward overlay frame data, the processor executes the instruction to:obtain the reconstructed forward overlay frame data in response to:a determination that the encoded forward overlay frame data indicates that the encoded forward overlay frame data is for an inter prediction coded frame;a determination that the encoded forward overlay frame data includes data indicating an order hint value of zero; anda determination that a most recently reconstructed frame is other than a keyframe;refreshing the reference frame buffer by:include the reconstructed forward no-show keyframe data in the reference frame buffer; andexclude reference frame data other than the reconstructed forward no-show keyframe data from the reference frame buffer;access, from the encoded forward overlay frame data, an index value of the reconstructed forward no-show keyframe data in the reference frame buffer; andobtain the forward no-show keyframe data from the reference frame buffer.

17. A non-transitory computer-readable storage medium having stored thereon an encoded bitstream comprising:encoded no-show keyframe data, wherein the encoded no-show keyframe data includes:data indicating that the encoded no-show keyframe data is for a keyframe; and data indicating that the encoded no-show keyframe data is for a no-show frame; andencoded overlay frame data corresponding to inter prediction coding using reconstructed no-show keyframe data corresponding to the encoded no-show keyframe data as available reference frame data.

18. The non-transitory computer-readable storage medium of claim 17, wherein the encoded overlay frame data includes data indicating output of reconstructed overlay frame data in response to decoding the encoded overlay frame data.

19. The non-transitory computer-readable storage medium of claim 17, wherein the encoded bitstream includes:subsequent to the encoded no-show keyframe data, encoded subsequent frame data for obtaining reconstructed subsequent frame data by decoding the encoded subsequent frame data using inter prediction using the reconstructed no-show keyframe data as available reference frame data.

20. The non-transitory computer-readable storage medium of claim 19, wherein the encoded bitstream includes:subsequent to the encoded subsequent frame data, encoded forward no-show keyframe data, wherein the encoded forward no-show keyframe data includes:data indicating that the encoded forward no-show keyframe data is for a keyframe;data indicating that the encoded forward no-show keyframe data is for a no- show frame; anddata indicating zero or more reference frames from a reference frame buffer to refresh;subsequent to the encoded forward no-show keyframe data, second encoded subsequent frame data for obtaining second reconstructed subsequent frame data by decoding the second encoded subsequent frame data using inter prediction using reconstructed forward no-show keyframe data corresponding to the encoded forward no-show keyframe data as available reference frame data; andsubsequent to the second encoded subsequent frame data, encoded forward overlay frame data for obtaining reconstructed forward overlay frame data by decoding the encoded forward overlay frame data using inter prediction using the reconstructed forward no-show keyframe data as available reference frame data.

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