Techniques for coding separated LUMA and chroma planes

Abstract

Coding separated luma and chroma planes includes receiving video data comprising at least one of a luma block associated with a luma coding tree unit or a chroma block associated with a chroma coding tree unit, determining a high-level partitioning scheme associated with the video data, where the high-level partitioning scheme corresponds to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit. The virtual coding tree unit is based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit. Coding separated luma and chroma planes includes coding the video data based on the high-level partitioning scheme.

Description

Atty. Doc. No. GOGL-2302-A-WOTECHNIQUES FOR CODING SEPARATED LUMA AND CHROMA PLANESCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to and the benefit of U.S. Provisional Application Patent Serial No. 63 / 774,367, filed March 19, 2025, the entire disclosure of which is hereby incorporated by reference.BACKGROUND

[0002] Digital video streams may represent video using a sequence of frames or still images. Digital video can be used for various applications including, for example, video conferencing, high- definition video entertainment, video advertisements, or sharing of usergenerated videos. A digital video stream can contain a large amount of data and consume a significant amount of computing or communication resources of a computing device for processing, transmission, or storage of the video data. Various approaches have been proposed to reduce the amount of data in video streams, including encoding or decoding techniques.SUMMARY

[0003] A first aspect is a method that includes receiving video data comprising at least one of a luma block associated with a luma coding tree unit (CTU) or a chroma block associated with a chroma coding tree unit. The method determines a high-level partitioning scheme associated with the video data, the high-level partitioning scheme corresponding to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit, wherein the virtual coding tree unit is based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit. The method codes the video data based on the high-level partitioning scheme.

[0004] A second aspect is a method that includes receiving video data comprising a luma block associated with a luma coding tree unit and a chroma block associated with a chroma coding tree unit. The method communicates a chroma quantization parameter (QP) information signal having a granularity corresponding to only a chroma coding tree unit level. The method codes the video data based on the chroma quantization parameter information.

[0005] A third aspect is a method that includes receiving video data comprising a luma block and an associated chroma block. The method codes the luma block based on at least one set of motion vectors. The method partitions, based on a geometric partitioning mode (GPM), the chroma block into a set of chroma subblocks. The method codes a chroma subblock of the set of chroma subblocks based on a motion vector of the at least one set of motion vectors.

[0006] A fourth aspect is a method that includes receiving video data comprising a luma block and an associated chroma inter block. The method codes the luma block based on a biprediction with coding unit-level weight (BCW) weighting. The method codes the chroma inter block based on a signaled bi-prediction with coding unit-level weight weighting or a default bi-prediction with coding unit-level weight weighting.

[0007] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The description herein makes reference to the accompanying drawings described below, wherein like reference numerals refer to like parts throughout the several views.

[0009] FIG. 1 is a diagram of a computing device in accordance with implementations of this disclosure.

[0010] FIG. 2 is a diagram of a computing and communications system in accordance with implementations of this disclosure.

[0011] FIG. 3 is a diagram of a video stream for use in encoding and decoding in accordance with implementations of this disclosure.

[0012] FIG. 4 is a block diagram of an encoder in accordance with implementations of this disclosure.

[0013] FIG. 5 is a block diagram of a decoder in accordance with implementations of this disclosure.

[0014] FIG. 6 is a block diagram of a representation of a portion of a frame in accordance with implementations of this disclosure.

[0015] FIG. 7 is a block diagram of examples of geometric partitions of a coding unit.

[0016] FIG. 8 is a flowchart of an example of processing video data with separated luma and chroma planes.

[0017] FIG. 9 is a flowchart of an example of processing video data with separated luma and chroma planes.

[0018] FIG. 10 is a flowchart of an example of coding video data with separated luma and chroma planes using geometric partitioning mode.

[0019] FIG. 11 is a flowchart of an example of coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight.DETAILED DESCRIPTION

[0020] Video compression schemes may include breaking respective images, or frames, of a video stream into smaller portions, such as blocks, or coding tree units (CTUs), and generating an encoded bitstream using techniques to limit the information included for respective coding tree units thereof. The bitstream can be decoded to re-create the source frames from the limited information. Encoding coding tree units to or decoding coding tree units from a bitstream can include predicting the values of pixels or coding tree units based on similarities with other pixels or coding tree units which have already been coded in the same frame, using intra-prediction, or in one or more different frames, using inter-prediction. Intra-prediction attempts to predict the pixel values of a coding unit of a coding tree unit using pixels peripheral to the coding unit (e.g., pixels that are in the same frame as the coding unit, but which are outside the coding unit). Inter-prediction attempts to predict the pixel values of a coding unit of a coding tree unit using pixels corresponding to the same video content in one or more other frames (e.g., pixels that are either co-located with the pixels of the coding unit in another frame or nearby the co-located portion of the coding unit in another frame).

[0021] During encoding, the result of an intra- or inter-prediction mode performed against a coding unit is a prediction unit (PU). A prediction residual can be determined based on a difference between the pixel values of the coding unit and the pixel values of the prediction unit. The prediction residual and the prediction mode used to ultimately obtain that prediction residual can then be encoded to a bitstream. During decoding, the prediction residual is reconstructed into a coding unit using a prediction unit produced based on the prediction mode and is thereafter included in an output video stream.

[0022] A coding unit includes a luminance, also referred to as luma, component and two chrominance, also referred to as chroma, components. These luma and chroma components may in some case be referred to as a luma block and chroma blocks. The luma component of a coding unit may, for example, be expressed within a Y plane of the coding unit and the chroma components may be expressed either within U and V planes or Cr and Cb planes of the coding unit. The luma component is understood to include some number of luma samplesand each chroma component is understood to include some number of chroma samples.Generally, the luma samples provide measures of brightness throughout a subject coding unit and thus represents the structural qualities of the video content of the subject coding unit, whereas the chroma samples provide measures of color throughout the subject coding unit. Because of this, conventional video compression schemes often use finer prediction approaches for predicting luma components of coding units than chroma components thereof. Such schemes may also use approaches directed to predicting those chroma components from the predicted luma components.

[0023] A frame can be divided into blocks (CTUs) of a maximum available size, often also referred to as superblocks. The partitioning strategies of coding tree units into coding units are signaled in a compressed bitstream. The partitioning of a coding tree unit can be hierarchical. That is, a coding tree unit may be recursively divided into progressively smaller coding units. The partitioning of a coding tree unit is communicated in the form of, or referred to as, a partition. The partition tree is a hierarchical structure that represents the division of a coding tree unit into smaller coding blocks. Each node in the tree corresponds to a block, with the root node representing the coding tree unit and the leaf nodes representing the smallest coding units.

[0024] At least in the case of a coding unit that is inter-predicted, conventional codecs signal a single block partition tree for the coding unit. The block partition tree is used for both the luma and chroma components of the coding unit. Thus, the same partition structure is applied to each of the luma Y, chroma U, and chroma V components of the coding unit. Interprediction broadly refers to any coding mode that leverages temporal similarities between the block in a current frame and other blocks within another frame that is different from the current frame.

[0025] To illustrate, in H.265 / HEVC (ITU-T Rec. H.265, “High Efficiency Video Coding”, December 2016), the coding tree of a coding tree unit (CTU) is shared by Y, U, and V components. In the joint exploration model (JEM), versatile video coding (VVC) codec, a single tree structure is used for P and B slices. However, the luma and chroma components may be encoded separately in I slices. As such, a luma coding tree unit (containing only one luma coding tree block of the original coding tree unit) forms one coding tree, and a chroma coding tree unit (containing only two chroma coding tree blocks of the original coding tree unit) forms a chroma separate tree (CST). The CST design in I slices may also be referred as “CTU dual tree.”

[0026] Another conventional approach interleaves luma component partition trees (i.e., luma trees) with chroma component partition trees (i.e., chroma trees). To illustrate, a bitstream may include, in the following order and with additional data (e.g., residual data) interspersed therebetween, a first luma tree for the luma component of a first coding unit, a first chroma tree for the chroma components of the first coding unit, a second luma tree for the luma component of a second coding unit, and a second chroma tree for the chroma components of the second coding unit.

[0027] In some cases, video compression with separated luma and chroma planes separates the luma coding tree units and chroma coding tree units into separate planes within a compressed bitstream. Each of the planes can be separately coded. As such, at least the coding of luma coding tree units can proceed independent of the coding of chroma coding tree units. Accordingly, parallelism can be improved over the traditional approaches.Furthermore, no special hardware / circuitry is required in hardware implementations as no special cases need be handled. Additionally, in low-bandwidth environments, a decoder may decode the luma signal and to ignore the chroma signal, therewith resulting in a monochrome video stream.

[0028] Moreover, separating the luma and chroma planes can improve the prediction quality for certain prediction modes whereby chroma blocks are predicted based on or from luma blocks. Where chroma blocks are predicted from luma blocks or images, as further described herein, the prediction can use post-filtered luma blocks or images. A post-filtered luma image can provide a better (e.g., improved or enhanced) luma signal over an only reconstructed set of luma blocks. Traditionally, such prediction is based on only reconstructed luma blocks or images since, in the case of luma coding tree unit and chroma coding tree unit interleaving, loop filtering and subsequently predicting chroma may be unavailable, such as wherein loop filtering is applied to both of the luma and chroma signals.

[0029] Some compression techniques include coding based on separated luma and chroma planes. With these methods, the luma plane and chroma planes are coded separately, while allowing prediction from the luma plane to chroma planes. Some coding techniques include chroma tree partitioning and prediction methods. As an example, a chroma inter / inter-block copy (IBC) prediction mode may be based on collocated luma motion vector (MV) / block vector (BV). Additionally, an MV / BV hole filling method may be used.

[0030] In VVC, a geometric partitioning mode (GPM) is supported for inter prediction. The geometric partitioning mode is signaled using a coding unit-level flag as one kind of merge mode, with other merge modes including the regular merge mode, the merge modewith motion vector difference (MMVD) mode, the combined inter and intra prediction (CIIP) mode, and the subblock merge mode. In total 64 partitions are supported by geometric partitioning mode for each available coding unit size excluding 8x64 and 64x8.

[0031] When this mode is used, a coding unit is split into two parts by a geometrically located straight line, as shown above. The location of the splitting line is mathematically derived from the angle and offset parameters of a specific partition. Each part of a geometric partition in the coding unit is inter-predicted using its own motion; only uni-prediction is allowed for each partition, that is, each part has one motion vector and one reference index. The uni-prediction motion constraint is applied to ensure that, same as the conventional biprediction, only two motion compensated predictions are needed for each coding unit. The uni-prediction motion for each partition is derived using a predefined process.

[0032] If geometric partitioning mode is used for the current coding unit, then a geometric partition index indicating the partition mode of the geometric partition (angle and offset), and two merge indices (one for each partition) are further signaled. The number of maximum geometric partitioning mode candidate size is signaled explicitly in a sequence parameter set (SPS) and specifies syntax binarization for geometric partitioning mode merge indices. After predicting each part of the geometric partition, the sample values along the geometric partition edge are adjusted using a blending processing with adaptive weights. This is the prediction signal for the whole coding unit, and the transform and quantization process will be applied to the whole coding unit as in other prediction modes. Finally, the motion field of a coding unit predicted using the geometric partition modes is stored based on a predefined process. However, such stored motion may not be good if it is used as motion for a rectangular block, which may happen in the case of separated luma and chroma planes.

[0033] In HEVC, the bi-prediction signal is generated by averaging two prediction signals obtained from two different reference pictures and / or using two different motion vectors. In VVC, the bi-prediction mode is extended beyond simple averaging to allow weighted averaging of the two prediction signals:Pbi- pred = ((8 - w) * Po+ w * Pj + 4) » 3,

[0034] where Pbi-pred is the bi-prediction signal, Poand P are the two prediction signals, and w is the weight.

[0035] Five weights are allowed in the weighted averaging bi-prediction. For each bipredicted coding unit, the weight w is determined in one of two ways: 1) for a non-merge coding unit, the weight index is signaled after the motion vector difference; or 2) for a mergecoding unit, the weight index is inferred from neighboring blocks based on the merge candidate index, bi-prediction with coding unit-level weight is only applied to coding units with 256 or more luma samples (e.g., coding unit width times coding unit height is greater than or equal to 256). For low-delay pictures, all 5 weights (wG { -2, 3, 4, 5, 10}) are used. For non-low-delay pictures, only 3 weights (wG {3, 4, 5}) are used.

[0036] VVC includes four different high-level picture partitioning schemes, namely subpictures, slices, tiles, and wavefront parallel processing (WPP). All these schemes are defined in the unit of coding tree unit.

[0037] A technical challenge arises from the potential misalignment between luma and chroma coding tree units (CTUs) when they are processed independently. This misalignment can occur due to different coding tree unit sizes or partitioning structures for luma and chroma components. As a result, high-level partitioning schemes such as subpictures, slices, and tiles, which are traditionally defined based on a unified coding tree unit grid, may no longer properly align across luma and chroma planes. This misalignment can lead to complications in implementing certain coding tools that rely on spatial correspondence between luma and chroma components.

[0038] Another technical issue stems from the application of prediction modes and coding tools that were originally designed for joint luma-chroma processing. For instance, geometric partitioning modes (GPM) and bi-prediction with coding unit-level weight (BCW) may not be directly applicable or optimal when luma and chroma planes are coded separately. The motion information derived for luma blocks may not be suitable for corresponding chroma blocks due to different partitioning structures, potentially leading to suboptimal motion compensation for chroma. Similarly, bi-prediction with coding unit-level weight weights determined based on luma characteristics may not provide the best prediction for chroma blocks, especially when luma and chroma have different spatial resolutions or statistical properties.

[0039] These challenges can result in reduced coding efficiency, increased computational complexity, and potential quality degradation in the compressed video. Additionally, the separate processing of luma and chroma planes may complicate the implementation of certain coding tools and require careful consideration of cross-component dependencies to maintain coding performance. Addressing these issues may be beneficial for developing nextgeneration video coding standards that can fully leverage the benefits of separated luma and chroma plane coding while maintaining or improving overall compression efficiency and visual quality.

[0040] Implementations of this disclosure address problems such as these by defining high-level partitioning schemes for video data with separated luma and chroma planes. In some implementations, the high-level partitioning scheme may correspond to a luma coding tree unit, a chroma coding tree unit, or a virtual coding tree unit. The virtual coding tree unit may be based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit. This approach allows for flexible partitioning that can accommodate different coding tree unit sizes for luma and chroma components while maintaining spatial alignment.

[0041] The term "high-level partitioning scheme" refers to a method of dividing video data into larger structural units for processing. This may include, but is not limited to, subpictures, slices, or tiles. For example, a high-level partitioning scheme might divide a frame into multiple tiles that can be processed independently. In some implementations, the high-level partitioning scheme may correspond to the luma coding tree unit when the partition unit comprises only a luma plane, or to the chroma coding tree unit when the partition unit comprises only a chroma plane. Alternatively, when the partition unit includes both luma and chroma planes, the scheme may correspond to the virtual coding tree unit.

[0042] Some implementations provide for efficient handling of wavefront parallel processing in the context of separated luma and chroma planes, wavefront parallel processing may be performed on the luma plane and the chroma plane separately and in parallel, potentially improving processing efficiency. This approach may also consider prediction dependencies from the luma plane when coding the chroma plane, maintaining important cross-component relationships while allowing for parallel processing.

[0043] The disclosure also addresses challenges related to quantization parameter (QP) signaling in separated plane coding. In some implementations, a chroma quantization parameter information signal may be communicated with a granularity corresponding to only a chroma coding tree unit level. This approach can reduce signaling overhead while still providing effective control over chroma quantization. All coding units within a chroma coding tree unit may be coded based on the same chroma quantization parameter information, which can simplify processing while maintaining coding efficiency.

[0044] Implementations of this disclosure may also improve the application of geometric partitioning mode to chroma coding in separated plane scenarios. The chroma block may be partitioned into a set of chroma subblocks based on geometric partitioning mode, and these subblocks may be coded based on motion vectors derived from the luma block coding. This approach allows for the benefits of geometric partitioning mode to be extended to chromacoding even when luma and chroma are processed separately. In some implementations, the coding of a chroma subblock may depend on the alignment state between the external boundaries of the inter chroma coding unit and the collocated luma coding unit, allowing for adaptive reuse of motion information.

[0045] Furthermore, some implementations provide solutions for applying bi-prediction with coding unit-level weight in the context of separated luma and chroma coding. In some implementations, the luma block may be coded based on bi-prediction with coding unit-level weight weighting, while the associated chroma inter block may be coded based on either a signaled bi-prediction with coding unit-level weight weighting or a default bi-prediction with coding unit- level weight weighting. This flexibility allows for optimized weighting in chroma prediction while managing signaling overhead. In some cases, all subblocks of a chroma inter block may use the same bi-prediction with coding unit-level weight weighting, which can simplify processing while still providing effective prediction.

[0046] The term "bi-prediction with coding unit-level weight" refers to a prediction mode where two prediction signals are combined using a weighted average, with the weights determined at the coding unit level. For example, in a scene with fading, different weights might be optimal for combining predictions from two different reference frames. Alternative implementations might include adaptive weight selection based on local image characteristics or the use of multiple weight sets for different regions within a coding unit.

[0047] These technical solutions provide a comprehensive approach to addressing the challenges of separated luma and chroma plane coding. By improving partitioning, parallel processing, quantization control, geometric partitioning, and weighted prediction, the disclosure enables more efficient and flexible video coding systems that can better adapt to the unique characteristics of luma and chroma information.

[0048] While the description herein is mainly described with respect to one color space, namely, the YUV color space, the disclosure is not so limited. Although terminology such as luma and chroma planes, or Y / U / V planes are used, the disclosure herein can be easily extended to other color formats, such as the YCoCg, YCbCr, RGB, or other color spaces. Additionally, according to the teachings herein, more planes can be included in a compressed bitstream. For example, the planes may include a transparency plane in addition to the luma and chroma planes or a depth plane in addition to the red, green, and blue planes.

[0049] Further details of techniques for coding separated luma and chroma planes are described herein with initial reference to a system in which they can be implemented.

[0050] FIG. 1 is a diagram of a computing device 100 in accordance with implementationsof 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.

[0051] 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.

[0052] The memory 110 (e.g., a non-transitory computer readable medium or a non-transitory computer readable storage medium) can include any non-transitory computer-usable or non-transitory 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, a floppy disk, an optical disk, a magnetic or optical card, one or more applicationspecific integrated circuits (ASICs), or any type of non-transitory media suitable for storing electronic information, or any combination thereof.

[0053] Although shown as 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.

[0054] 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. Theinstructions 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.

[0055] 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.

[0056] 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 microprocessors 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.

[0057] 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.

[0058] 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, avisible 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.

[0059] 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.

[0060] 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, the sensor 150 may include a sound-sensing device, such as a microphone, or any other sound-sensing 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 is shown, 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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 source 160, and the bus 170, or any combination thereof can be integrated in one or more electronic units, circuits, or chips.

[0066] 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.

[0067] 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 100 A, 100B may be user devices, such as a mobile computing device, a laptop, a thin client, or a smartphone, and the computing andcommunication device 100C may be a server, such as a mainframe or a cluster. Although the computing and communication device 100 A 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 100 A and the computing and communication device 100B may receive, decode, process, store, present, or a combination thereof the audio data.

[0068] 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. Although each computing and communication device 100 A, 100B, 100C is shown as a single unit, a computing and communication device can include any number of interconnected elements.

[0069] Each access point 210A, 210B 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.

[0070] 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 (LAN), 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), theHyperText Transport Protocol (HTTP), or a combination thereof.

[0071] The computing and communication devices 100A, 100B, 100C can communicate with each other via the network 220 using one or more 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 100 A 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, 100C in 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.

[0072] In some implementations, communications between one or more of the computing and communication device 100 A, 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 100 A 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 100 A or the computing and communication device 100B.

[0073] 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, thecomputing and communications system 200 may include many more communicating devices, networks, and access points.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 bythe 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.

[0078] 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.

[0079] 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. Interprediction 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.

[0080] 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.

[0081] 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.

[0082] 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 the broken 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.

[0083] 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.

[0084] 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.

[0085] 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, adequantization 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.

[0086] 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 or combinations of types of filtering, and which may include generating a reconstructed block, which may be output as the output video stream 504.

[0087] 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.

[0088] 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 pixels690. 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.

[0089] 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 64x64 block in the left column of the second row may be coded after the 64x64 block in the rightmost column of the first row.

[0090] 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.

[0091] 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.

[0092] 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 range from 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.

[0093] 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.

[0094] 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.

[0095] 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 inmemory, 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.

[0096] 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 as differential 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 / x,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.

[0097] 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.

[0098] In some implementations, block-based coding efficiency may be improved bypartitioning 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.

[0099] 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.

[0100] 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 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 candidateprediction 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.

[0101] 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.

[0102] 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 two hundred fifty six (256) 4x4 transform blocks.

[0103] 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.

[0104] FIG. 7 is a block diagram of examples of geometric partitions 700 of a coding unit. Twenty-four example coding units are shown each with multiple example splitting lines, depicting at least some of the available geometric partitions into which a given coding unit may be split within its external boundary. As has been mentioned above, a coding unit is partitioned into two geometric partitions in which the splitting line represents the boundary between those two geometric partitions. The location of the splitting line for a given geometric partition is derived from the angle and offset parameters of that partition.

[0105] FIG. 8 is a flowchart of an example of processing video data with separated luma and chroma planes 800. Processing video data with separated luma and chroma planes 800 can be implemented, for example, as a software program that may be executed by computing devices, such as in an encoder, such as the encoder 400 shown in FIG. 4, a decoder, such as the decoder 500 shown in FIG. 5, or both. The software program can include machine-readable instructions that may be stored in a memory, such as the memory 110 shown in FIG.1, and that, when executed by a processor, such as processor 120 shown in FIG. 1, may cause the computing device to perform processing video data with separated luma and chroma planes 800. Processing video data with separated luma and chroma planes 800 may be implemented, in whole or in part, by a component, or stage, of the encoder, such as the intra / inter prediction unit 410 shown in FIG. 4, or a component, or stage, of the decoder, such as the intra / inter prediction unit 540 shown in FIG. 5. Processing video data with separated luma and chroma planes 800 can be implemented using specialized hardware or firmware. Multiple processors, memories, or both, may be used.

[0106] Processing video data with separated luma and chroma planes 800 includes receiving, reading, obtaining, or otherwise accessing, input video data (at 810) comprising at least one of a luma block associated with a luma coding tree unit or a chroma block associated with a chroma coding tree unit. For example, the video data may be received as part of a video stream, such as the video stream 300 shown in FIG. 3. In some implementations, the video data may include both luma and chroma blocks, while in other implementations, only luma or only chroma blocks may be received. The luma and chroma blocks may be associated with separate coding tree units, allowing for independent processing of luma and chroma information.

[0107] Processing video data with separated luma and chroma planes 800 includes determining a high-level partitioning scheme associated with the video data (at 820). The high-level partitioning scheme may correspond to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit. In some implementations, the virtual coding treeunit may be based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit. This approach allows for flexible partitioning that can accommodate different coding tree unit sizes for luma and chroma components while maintaining spatial alignment.

[0108] The high-level partitioning scheme may be indicative of a partition unit comprising at least one of a subpicture, a slice, or a tile, such as shown in FIG. 3. In some implementations, the high-level partitioning scheme may correspond to the luma coding tree unit when the partition unit comprises only a luma plane, or to the chroma coding tree unit when the partition unit comprises only a chroma plane. In some implementations, when the partition unit includes both luma and chroma planes, the scheme may correspond to the virtual coding tree unit.

[0109] In some implementations, the high-level partitioning scheme may include wavefront parallel processing. When the video data includes both luma and chroma blocks, processing video data with separated luma and chroma planes 800 may involve performing wavefront parallel processing on the luma plane and the chroma plane separately and in parallel. This approach can improve processing efficiency by allowing simultaneous processing of luma and chroma information.

[0110] Processing video data with separated luma and chroma planes 800 includes coding the video data based on the high-level partitioning scheme (at 830). Coding the video data based on the high-level partitioning scheme (at 830) may involve encoding or decoding the video data, depending on whether processing video data with separated luma and chroma planes 800 is implemented in the encoder or the decoder. The coding process may utilize the partitioning information determined in determining a high-level partitioning scheme associated with the video data (at 820) to efficiently process the video data.

[0111] When coding the video data, processing video data with separated luma and chroma planes 800 may take into account various factors. For example, if the high-level partitioning scheme corresponds to the luma coding tree unit based on the partition unit comprising only a luma plane, the coding process may be optimized for luma-only data. Similarly, if the scheme corresponds to the chroma coding tree unit based on the partition unit comprising only a chroma plane, the coding may be tailored for chroma- specific processing.

[0112] In implementations where the high-level partitioning scheme corresponds to the virtual coding tree unit based on the partition unit comprising both a luma plane and a chroma plane, the coding process may need to handle the relationship between luma and chroma data.This may involve coordinating the processing of luma and chroma information to maintain proper spatial and temporal relationships between the color components.

[0113] When wavefront parallel processing is used with the high-level partitioning scheme, the coding process in coding the video data based on the high-level partitioning scheme (at 830) may involve parallel processing of different wavefronts. In some implementations, this may include coding the chroma block based on one or more prediction dependencies from the luma plane. For example, the chroma coding may use information from the luma plane to improve prediction accuracy, even while the luma and chroma planes are processed in parallel.

[0114] Processing video data with separated luma and chroma planes 800 may be adapted to handle various video formats and coding standards. For instance, it may be applied to different chroma subsampling formats (e.g., 4:2:0, 4:2:2, or 4:4:4) or to different color spaces beyond YUV, such as RGB or YCoCg. The flexibility of the high-level partitioning scheme allows the technique to be tailored to the specific requirements of different video coding applications and scenarios.

[0115] At the encoder, the encoded data is included in an output, compressed, or encoded, bitstream, which is output, such as stored or transmitted, such as to a decoder, (at 840).

[0116] At the decoder, the decoded, or reconstructed, data is included in reconstructed video data, which is output such as for presentation to a user or storage (at 840).

[0117] FIG. 9 is a flowchart of an example of processing video data with separated luma and chroma planes 900. Processing video data with separated luma and chroma planes 900 can be implemented, for example, as a software program that may be executed by computing devices, such as in an encoder, such as the encoder 400 shown in FIG. 4, a decoder, such as the decoder 500 shown in FIG. 5, or both. The software program can include machine-readable instructions that may be stored in a memory, such as the memory 110 shown in FIG.1, and that, when executed by a processor, such as processor 120 shown in FIG. 1, may cause the computing device to perform processing video data with separated luma and chroma planes 900. Processing video data with separated luma and chroma planes 900 may be implemented, in whole or in part, by a component, or stage, of the encoder, such as the intra / inter prediction unit 410 shown in FIG. 4, or a component, or stage, of the decoder, such as the intra / inter prediction unit 540 shown in FIG. 5. Processing video data with separated luma and chroma planes 900 can be implemented using specialized hardware or firmware. Multiple processors, memories, or both, may be used.

[0118] Processing video data with separated luma and chroma planes 900 includes receiving video data (at 910) comprising a luma block associated with a luma coding tree unit and a chroma block associated with a chroma coding tree unit. For example, the video data may be received as part of a video stream, such as the video stream 300 shown in FIG. 3. In some implementations, the luma and chroma blocks may be associated with separate coding tree units, allowing for independent processing of luma and chroma information. This separation of luma and chroma planes can provide flexibility in coding and may improve coding efficiency for certain types of video content.

[0119] The luma block and chroma block received in receiving video data (at 910) may correspond to different color components of the same spatial region in a video frame. For instance, in a YUV color space, the luma block may represent the Y (luminance) component, while the chroma block may represent either the U or V (chrominance) component. In some implementations, the chroma block may have a different resolution than the luma block, such as in 4:2:0 chroma subsampling where the chroma resolution is half that of the luma in both horizontal and vertical directions.

[0120] Processing video data with separated luma and chroma planes 900 includes signaling (at 920) a chroma quantization parameter information signal having a granularity corresponding to only a chroma coding tree unit level. This addresses the challenge of efficiently signaling quantization information for chroma components when luma and chroma are processed separately. By limiting the granularity of chroma quantization parameter information to the coding tree unit level, the technique can reduce signaling overhead while still providing effective control over chroma quantization.

[0121] The communication of the chroma quantization parameter information signal may occur in various ways depending on whether processing video data with separated luma and chroma planes 900 is being used for encoding or decoding. In an encoding scenario, this step may involve determining an appropriate chroma quantization parameter value for the coding tree unit and including this information in the encoded bitstream. In a decoding scenario, it may involve parsing the chroma quantization parameter information from the received bitstream. This approach to chroma quantization parameter signaling can be particularly beneficial in the context of separated luma and chroma planes, as it allows for independent control of chroma quantization without requiring quantization parameter information at a finer granularity.

[0122] In some implementations, the chroma quantization parameter information may be independent of luma quantization parameter information associated with the luma block. Thisindependence allows for greater flexibility in optimizing the quantization of chroma components separately from luma components. For example, in scenes with subtle color variations but strong luminance contrasts, an encoder might choose to use a lower quantization parameter (finer quantization) for chroma while using a higher quantization parameter (coarser quantization) for luma to preserve color fidelity while achieving higher compression of luminance information.

[0123] Processing video data with separated luma and chroma planes 900 includes coding the video data (at 930) based on the chroma quantization parameter information. The coding process may involve either encoding or decoding, depending on the context in which processing video data with separated luma and chroma planes 900 is implemented. In an encoding scenario, this step may include applying the chroma quantization parameter to transform coefficients of the chroma block during quantization. In a decoding scenario, it may involve using the chroma quantization parameter information during the dequantization process to reconstruct the chroma block.

[0124] When coding the video data, all coding units within the chroma coding tree unit may be coded based on the same chroma quantization parameter information. This approach simplifies the coding process and reduces the amount of quantization parameter information that needs to be signaled or stored. It leverages the observation that chroma information often varies more slowly across a frame than luma information, making it reasonable to use the same quantization parameter for an entire chroma coding tree unit in many cases.

[0125] The coding process in coding the video data (at 930) may also take into account the relationship between the luma and chroma blocks, even though they are associated with separate coding tree units. For example, in some implementations, the technique may use information from the luma block to improve the prediction or coding of the chroma block. This could include methods such as cross-component prediction, where reconstructed luma samples are used to predict chroma samples.

[0126] In some implementations, processing video data with separated luma and chroma planes 900 may be adapted to handle various chroma subsampling formats beyond 4:2:0, such as 4:2:2 or 4:4:4. The approach to chroma quantization parameter signaling and coding may be adjusted based on the specific subsampling format used. For instance, in a 4:4:4 format where chroma has the same resolution as luma, the technique might allow for more fine-grained control of chroma quantization parameter, potentially signaling quantization parameter information at a level below the coding tree unit.

[0127] Processing video data with separated luma and chroma planes 900 may also be extended to support additional features related to chroma coding in the context of separated luma and chroma planes. For example, it may incorporate adaptive quantization parameter selection methods that choose the optimal chroma quantization parameter based on characteristics of the video content, such as the amount of color detail or the presence of specific color patterns. Such adaptive methods could potentially improve coding efficiency while still maintaining the simplicity of coding tree unit-level chroma quantization parameter signaling.

[0128] At the encoder, the encoded data is included in an output, compressed, or encoded, bitstream, which is output, such as stored or transmitted, such as to a decoder, (at 940).

[0129] At the decoder, the decoded, or reconstructed, data is included in reconstructed video data, which is output such as for presentation to a user or storage (at 940).

[0130] FIG. 10 is a flowchart of an example of coding video data with separated luma and chroma planes using geometric partitioning mode 1000. Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 can be implemented, for example, as a software program that may be executed by computing devices, such as in an encoder, such as the encoder 400 shown in FIG. 4, a decoder, such as the decoder 500 shown in FIG. 5, or both. The software program can include machine-readable instructions that may be stored in a memory, such as the memory 110 shown in FIG.1, and that, when executed by a processor, such as processor 120 shown in FIG. 1, may cause the computing device to perform coding video data with separated luma and chroma planes using geometric partitioning mode 1000. Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may be implemented, in whole or in part, by a component, or stage, of the encoder, such as the intra / inter prediction unit 410 shown in FIG.4, or a component, or stage, of the decoder, such as the intra / inter prediction unit 540 shown in FIG. 5. Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 can be implemented using specialized hardware or firmware.Multiple processors, memories, or both, may be used.

[0131] Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 includes receiving video data (at 1010) comprising a luma block and an associated chroma block. For example, the video data may be received as part of a video stream 300 as shown in FIG. 3. In some implementations, the luma and chroma blocks may be associated with separate coding tree units, allowing for independent processing of lumaand chroma information. This separation of luma and chroma planes can provide flexibility in coding and may improve coding efficiency for certain types of video content.

[0132] The luma block and chroma block received in receiving video data (at 1010) may correspond to different color components of the same spatial region in a video frame. For instance, in a YUV color space, the luma block may represent the Y (luminance) component, while the chroma block may represent either the U or V (chrominance) component. In some implementations, the chroma block may have a different resolution than the luma block, such as in 4:2:0 chroma subsampling where the chroma resolution is half that of the luma in both horizontal and vertical directions.

[0133] Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 includes coding the luma block (at 1020) based on at least one set of motion vectors. This may involve various prediction modes, such as inter-prediction or intraprediction. In the case of inter-prediction, the coding process may use motion vectors to identify reference blocks in previously coded frames that are similar to the current luma block.

[0134] In some implementations, the coding of the luma block may involve advanced techniques such as bi-prediction with coding unit-level weight , as described above. This approach allows for weighted averaging of two prediction signals, potentially improving the accuracy of the prediction and, consequently, the coding efficiency.

[0135] Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 includes partitioning (at 1030), based on a geometric partitioning mode, the chroma block into a set of chroma subblocks. This leverages the geometric partitioning mode concept described earlier in the specification, where a coding unit can be split into two parts by a geometrically located straight line. The geometric partitioning patterns, such as shown in FIG. 7, provide a range of available ways to divide the chroma block.

[0136] In some implementations, the partitioning of the chroma block may be independent of the partitioning used for the luma block. This flexibility can allow for more efficient coding of chroma information, especially in cases where the color variation in a region doesn't correspond directly to luminance variations. However, in other implementations, the chroma partitioning may be derived from or influenced by the luma partitioning to maintain a relationship between luma and chroma coding structures.

[0137] Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 includes coding a chroma subblock (at 1040) of the set of chromasubblocks based on a motion vector of the at least one set of motion vectors. This involves applying motion compensation to the chroma subblocks using motion information derived from the luma coding process. In some implementations, this may involve reusing or adapting the motion vectors used for the corresponding luma region.

[0138] The coding of the chroma subblock (at 1040) may depend on the alignment between the chroma and luma coding units. In some implementations, if an inter chroma coding unit is determined to be collocated with a luma coding unit that is a geometric partitioning mode block, the coding process may consider the alignment state between the external boundaries of the inter chroma coding unit and the collocated luma coding unit. If the boundaries are aligned, the set of motion vectors used for the luma coding unit may be directly reused for coding the chroma subblock. If the boundaries are not aligned, the coding process may reuse motion vectors from a regular rectangular luma subblock of the collocated luma coding unit.

[0139] In some implementations, coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may include additional steps or variations. For example, coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may incorporate adaptive methods for selecting the best partitioning mode or motion vector reuse strategy based on the characteristics of the video content.Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may also include handling special cases, such as when the chroma resolution differs significantly from the luma resolution, or when certain types of prediction modes are used for the luma block.

[0140] Coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may be adapted to support various video coding standards and formats. For instance, it may be applied to different chroma subsampling formats (e.g., 4:2:0, 4:2:2, or 4:4:4) or to different color spaces beyond YUV, such as RGB or YCoCg. The flexibility of the geometric partitioning mode and the separate handling of luma and chroma blocks allow the technique to be tailored to the specific requirements of different video coding applications and scenarios.

[0141] In some implementations, coding video data with separated luma and chroma planes using geometric partitioning mode 1000 may be combined with other coding tools and techniques described earlier in the specification. For example, it may be used in conjunction with the high-level partitioning schemes described in relation to FIG. 8, or with the chroma quantization parameter handling described in relation to FIG. 9. This combination oftechniques can provide a comprehensive approach to coding video with separated luma and chroma planes, potentially leading to improvements in both coding efficiency and flexibility.

[0142] At the encoder, the encoded data is included in an output, compressed, or encoded, bitstream, which is output, such as stored or transmitted, such as to a decoder, (at 1050).

[0143] At the decoder, the decoded, or reconstructed, data is included in reconstructed video data, which is output such as for presentation to a user or storage (at 1050).

[0144] FIG. 11 is a flowchart of an example of coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100. The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 can be implemented, for example, as a software program that may be executed by computing devices, such as in an encoder, such as the encoder 400 shown in FIG. 4, a decoder, such as the decoder 500 shown in FIG. 5, or both. The software program can include machine-readable instructions that may be stored in a memory, such as the memory 110 shown in FIG. 1, and that, when executed by a processor, such as processor 120 shown in FIG. 1, may cause the computing device to perform processing video data with separated luma and chroma planes 800. Processing video data with separated luma and chroma planes 800 may be implemented, in whole or in part, by a component, or stage, of the encoder, such as the intra / inter prediction unit 410 shown in FIG. 4, or a component, or stage, of the decoder, such as the intra / inter prediction unit 540 shown in FIG. 5. Processing video data with separated luma and chroma planes 800 can be implemented using specialized hardware or firmware. Multiple processors, memories, or both, may be used.

[0145] The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 includes receiving video data (at 1110) comprising a luma block and an associated chroma inter block. For example, the video data may be received as part of a video stream, such as the video stream 300 shown in FIG. 3. In some implementations, the luma and chroma blocks may be associated with separate coding tree units, allowing for independent processing of luma and chroma information. This separation of luma and chroma planes can provide flexibility in coding and may improve coding efficiency for certain types of video content.

[0146] The luma block and chroma inter block received in receiving video data (at 1110) may correspond to different color components of the same spatial region in a video frame. For instance, in a YUV color space, the luma block may represent the Y (luminance) component, while the chroma inter block may represent either the U or V (chrominance) component. In some implementations, the chroma inter block may have a different resolutionthan the luma block, such as in 4:2:0 chroma subsampling where the chroma resolution is half that of the luma in both horizontal and vertical directions.

[0147] The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 includes coding the luma block based on a bi-prediction with coding unit-level weight weighting (at 1120). This involves using bi-prediction with coding unit-level weight , as described earlier in the specification, where the bi-prediction signal is generated by weighted averaging of two prediction signals. In some codecs, the biprediction mode extends beyond simple averaging to allow weighted averaging of the two prediction signals, wherein where Pbi-pred is the bi-prediction signal, Poand P are the two prediction signals, and w is the weight, which may be expressed as the following:Pbi- pred = ((8 - w) * Po+ w * Pj + 4) » 3.

[0148] In some implementations, five weights may be allowed in the weighted averaging bi-prediction. For each bi-predicted coding unit, the weight w may be determined in one of two ways: 1) for a non-merge coding unit, the weight index may be signaled after the motion vector difference; or 2) for a merge coding unit, the weight index may be inferred from neighboring blocks based on the merge candidate index, bi-prediction with coding unit-level weight may only be applied to coding units with 256 or more luma samples (e.g., coding unit width times coding unit height is greater than or equal to 256).

[0149] The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 includes coding the chroma inter block (at 1130) based on a signaled bi-prediction with coding unit-level weight weighting or a default bi-prediction with coding unit-level weight weighting. This addresses the challenge of efficiently applying bi-prediction with coding unit-level weight to chroma coding when luma and chroma are processed separately. In some implementations, the coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 may involve communicating a signal indicative of the signaled bi-prediction with coding unit-level weight weighting. This allows for flexibility in choosing whether to use a signaled weighting specific to the chroma block or a default weighting.

[0150] The choice between using a signaled bi-prediction with coding unit-level weight weighting or a default bi-prediction with coding unit-level weight weighting for the chroma inter block may depend on various factors. For example, in some implementations, the decision may be based on the characteristics of the video content, such as the amount of color detail or the presence of specific color patterns. In other implementations, the choice may beinfluenced by rate-distortion optimization considerations, balancing the potential improvement in prediction accuracy against the cost of signaling additional weighting information.

[0151] In some implementations, coding the chroma inter block may involve coding all subblocks of the chroma inter block using the same bi-prediction with coding unit-level weight weighting, comprising either the signaled bi-prediction with coding unit-level weight weighting or the default bi-prediction with coding unit- level weight weighting. This approach can simplify the coding process and reduce the amount of weighting information that needs to be signaled or stored. It leverages the observation that chroma information often varies more slowly across a frame than luma information, making it reasonable to use the same weighting for an entire chroma inter block in many cases.

[0152] The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 may be adapted to support various video coding standards and formats. For instance, it may be applied to different chroma subsampling formats (e.g., 4:2:0, 4:2:2, or 4:4:4) or to different color spaces beyond YUV, such as RGB or YCoCg. The flexibility in handling bi-prediction with coding unit-level weight for separated luma and chroma planes allows the technique to be tailored to the specific requirements of different video coding applications and scenarios.

[0153] In some implementations, the coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 may incorporate adaptive methods for selecting the best bi-prediction with coding unit-level weight strategy based on the characteristics of the video content. For example, it may include steps for analyzing the correlation between luma and chroma information to determine whether using the same biprediction with coding unit-level weight weights for both components is likely to be effective, or whether separate weights should be signaled for chroma.

[0154] The coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 may also be combined with other coding tools and techniques described earlier in the specification. For example, it may be used in conjunction with the high-level partitioning schemes described in relation to FIG. 8, or with the chroma quantization parameter handling described in relation to FIG. 9. This combination of techniques can provide a comprehensive approach to coding video with separated luma and chroma planes, potentially leading to improvements in both coding efficiency and flexibility.

[0155] In alternative embodiments, the coding video data with separated luma and chroma planes using bi-prediction with coding unit-level weight 1100 may be extended tosupport more complex weighting schemes. For instance, instead of using a single weight for the entire coding unit, multiple weights could be used for different regions within the coding unit. This could potentially improve prediction accuracy for coding units with varying characteristics, at the cost of increased complexity and signaling overhead.

[0156] At the encoder, the encoded data is included in an output, compressed, or encoded, bitstream, which is output, such as stored or transmitted, such as to a decoder, (at 1140).

[0157] At the decoder, the decoded, or reconstructed, data is included in reconstructed video data, which is output such as for presentation to a user or storage (at 1140).

[0158] The aspects of encoding and decoding described above illustrate some examples of encoding and decoding techniques. However, it is to be understood that encoding and decoding, as those terms are used in the claims, could mean compression, decompression, transformation, or any other processing or change of data.

[0159] 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.

[0160] 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.

[0161] The words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as an “example” or “exemplary” is 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 otherwiseidentifying or determining in any manner whatsoever using one or more of the devices shown in FIG. 1.

[0162] 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 from implementations of methods in accordance with the disclosed subject matter.

[0163] The implementations of the transmitting computing and communication device 100 A and / or the receiving computing and communication device 100B (and the algorithms, methods, instructions, etc. stored thereon and / or executed thereby) can be realized in hardware, 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.

[0164] Further, in one implementation, for example, the transmitting computing and communication device 100 A 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.

[0165] The transmitting computing and communication device 100 A 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 100 A 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 100 A can encode content using an encoder 400 into an encoded videosignal 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 100 A 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.

[0166] 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.

[0167] 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.

[0168] 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 for coding, the method comprising:receiving video data comprising at least one of a luma block associated with a luma coding tree unit or a chroma block associated with a chroma coding tree unit;determining a high-level partitioning scheme associated with the video data, the high-level partitioning scheme corresponding to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit, wherein the virtual coding tree unit is based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit; andcoding the video data based on the high-level partitioning scheme.

2. The method of claim 1, wherein the high-level partitioning scheme is indicative of a partition unit comprising at least one of a subpicture, a slice, or a tile.

3. The method of claim 2, wherein the high-level partitioning scheme corresponds to the luma coding tree unit based on the partition unit comprising only a luma plane.

4. The method of claim 2, wherein the high-level partitioning scheme corresponds to the chroma coding tree unit based on the partition unit comprising only a chroma plane.

5. The method of claim 2, wherein the high-level partitioning scheme corresponds to the virtual coding tree unit based on the partition unit comprising a luma plane and a chroma plane.

6. The method of claim 1, wherein the high-level partitioning scheme includes wavefront parallel processing and the video data includes the luma block and the chroma block, and coding the video data comprises: performing wavefront parallel processing on a luma plane and a chroma plane separately and in parallel.

7. The method of claim 6, wherein coding the video data comprises: coding the chroma block based on one or more prediction dependencies from the luma plane.

8. The method of claim 1, wherein coding comprises encoding or decoding.

9. An apparatus comprising:a non-transitory computer-readable medium storing instructions for processing video data with separated luma and chroma planes; anda processor configured to execute the instructions to:receive video data comprising at least one of a luma block associated with a luma coding tree unit or a chroma block associated with a chroma coding tree unit; determine a high-level partitioning scheme associated with the video data, the high-level partitioning scheme corresponding to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit, wherein the virtual coding tree unit is based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit; andcode the video data based on the high-level partitioning scheme.

10. The apparatus of claim 9, wherein the high-level partitioning scheme is indicative of a partition unit comprising at least one of a subpicture, a slice, or a tile.

11. The apparatus of claim 10, wherein the high-level partitioning scheme corresponds to the luma coding tree unit based on the partition unit comprising only a luma plane.

12. The apparatus of claim 10, wherein the high-level partitioning scheme corresponds to the chroma coding tree unit based on the partition unit comprising only a chroma plane.

13. The apparatus of claim 10, wherein the high-level partitioning scheme corresponds to the virtual coding tree unit based on the partition unit comprising a luma plane and a chroma plane.

14. The apparatus of claim 9, wherein:the high-level partitioning scheme includes wavefront parallel processing;the video data includes the luma block and the chroma block; andto code the video data the processor executes the instructions to perform wavefront parallel processing on a luma plane and a chroma plane separately and in parallel.

15. The apparatus of claim 14, wherein to code the video data the processor executes the instructions to code the chroma block based on one or more prediction dependencies from the luma plane.

16. The apparatus of claim 9, wherein to code the video data the processor executes the instructions to encode the video data to obtain an encoded bitstream.

17. The apparatus of claim 9, wherein to code the video data the processor executes the instructions to decode the video data to obtain a reconstructed video stream.

18. A non-transitory computer-readable storage medium having stored thereon executable instructions that, when executed by one or more processors of an image capture apparatus, cause the image capture apparatus to:receive video data comprising at least one of a luma block associated with a luma coding tree unit or a chroma block associated with a chroma coding tree unit;determine a high-level partitioning scheme associated with the video data, the high-level partitioning scheme corresponding to the luma coding tree unit, the chroma coding tree unit, or a virtual coding tree unit, wherein the virtual coding tree unit is based on a least common multiple of a width and a height of the luma coding tree unit and the chroma coding tree unit; andcode the video data based on the high-level partitioning scheme.

19. The non-transitory computer- readable storage medium of claim 18, wherein the high-level partitioning scheme is indicative of a partition unit comprising at least one of a subpicture, a slice, or a tile.

20. The non-transitory computer-readable storage medium of claim 18, wherein:the high-level partitioning scheme includes wavefront parallel processing;the video data includes the luma block and the chroma block; andinstructions comprise instructions to perform wavefront parallel processing on a luma plane and a chroma plane separately and in parallel.

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