Video data encoding and decoding using coded picture buffers

Abstract

An apparatus comprising a video data decoder; and a coded picture buffer buffering successive portions of an input video data stream and providing a portion to the video data decoder for decoding, the coded picture buffer having a coded picture buffer size; the video data decoder being responsive to parameter data associated with the input video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given input video data stream, each level defining at least a maximum luma picture size, a minimum compression ratio and a maximum value of the coded picture buffer size; wherein for each coding level of the plurality of coding levels, the maximum value of the coded picture buffer size is greater than or equal to a number of bits required to represent a picture at the maximum luma picture size when encoded according to the minimum compression ratio.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to video data encoding and decoding. BACKGROUND

[0002] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that can not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0003] There are several systems, e.g. video or image data encoding and decoding systems, which involve converting video data into a frequency domain representation, quantizing the frequency domain coefficients, and then applying some form of entropy coding to the quantized coefficients. This can enable compression of the video data. A corresponding decoding or decompression technique is applied to recover a reconstructed version of the original video data. SUMMARY

[0004] The present disclosure addresses or mitigates problems caused by this process.

[0005] Various aspects and features of the disclosure are defined in the appended claims.

[0006] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present technology. BRIEF DESCRIPTION OF DRAWINGS

[0007] A more complete understanding of the present disclosure and the many attendant advantages thereof will be readily understood by reference to the following detailed description when considered in conjunction with the drawings, wherein:

[0008] Figure 1 An audio / video (A / V) data transmission and reception system using video data compression and decompression is schematically illustrated;

[0009] Figure 2 A video display system using video data decompression is schematically illustrated;

[0010] Figure 3 An audio / video storage system using video data compression and decompression is schematically illustrated;

[0011] Figure 4 A video camera using video data compression is schematically illustrated;

[0012] Figure 5 And Figure 6 A storage medium is schematically illustrated;

[0013] Figure 7 A schematic diagram of a video data compression and decompression apparatus is provided;

[0014] Figure 8 a predictor is schematically illustrated;

[0015] Figure 9 use of a parameter set is schematically illustrated;

[0016] Figure 10 a decoding apparatus is schematically illustrated;

[0017] Figure 11 an encoding apparatus is schematically illustrated;

[0018] Figures 12 to 20 is a table relating to an encoding level; and

[0019] Figures 21 to 25 is a schematic flow diagram illustrating the respective method. DETAILED DESCRIPTION

[0020] Reference will now be made to the drawings, in which Figures 1 to 4 to give a schematic overview of an apparatus or system using compression and / or decompression apparatuses described below in connection with embodiments of the present technology.

[0021] All data compression and / or decompression apparatuses to be described below can be implemented in hardware, software running on a general purpose data processing apparatus such as a general purpose computer, programmable hardware such as an application specific integrated circuit (ASIC) or field programmable gate array (FPGA) or a combination of these. Where embodiments are implemented by software and / or firmware, it will be appreciated that such software and / or firmware, and non-transitory data storage media storing or otherwise providing such software or firmware, are considered to be embodiments of the present technology.

[0022] Figure 1 An audio / video data transmission and reception system using video data compression and decompression is schematically illustrated. In this example, the data values to be encoded or decoded represent image data.

[0023] An input audio / video signal 10 is provided to a video data compression apparatus 20 which at least compresses the video component of the audio / video data 10 for transmission along a transmission path 30 (e.g. a cable, optical fibre, wireless link, etc.). The compressed signal is processed by a decompression apparatus 40 to provide an output audio / video signal 50. For the return path, a compression apparatus 60 compresses the audio / video information for transmission along the transmission path 30 to a decompression apparatus 70.

[0024] Thus, the compression apparatus 20 and the decompression apparatus 70 can form one node of a transmission link. The decompression apparatus 40 and the decompression apparatus 60 can form the other node of the transmission link. Of course, in the case of a one-way transmission link, only one node requires a compression apparatus, while the other node only requires a decompression apparatus.

[0025] Figure 2 A video display system using video data decompression is shown schematically. In particular, a compressed audio / video signal 100 is processed by a decompression apparatus 110 to provide a decompressed signal that can be displayed on a display 120. The decompression apparatus 110 can be implemented as an integral part of the display 120, for example provided within the same housing as the display device. Alternatively, the decompression apparatus 110 can be provided as, for example, a so-called set-top box (STB), noting that the expression "set-top box" does not imply that the set-top box is required to be positioned in any particular orientation or location relative to the display 120; it is simply a term used in the art to indicate a device that can be connected to a display as a peripheral device.

[0026] Figure 3 An audio / video storage system using video data compression and decompression is shown schematically. An input audio / video signal 130 is provided to a compression apparatus 140, which generates a compressed signal for storage by a storage device 150 (for example a magnetic disk device, an optical disk device, a magnetic tape device, a solid state storage device such as a semiconductor memory, or other storage device). For playback, the compressed data is read from the storage device 150 and passed to a decompression apparatus 160 for decompression to provide an output audio / video signal 170.

[0027] It will be appreciated that a compressed or encoded signal, and a storage medium (for example a machine-readable non-transitory storage medium) storing the signal, are considered to be embodiments of the present technology.

[0028] Figure 4 A video camera using video data compression is shown schematically. In Figure 4 In particular, an image capture device 180 (for example a charge-coupled device (CCD) image sensor and associated control and readout electronics) generates a video signal that is passed to a compression apparatus 190. A microphone (or microphones) 200 generates an audio signal that is passed to the compression apparatus 190. The compression apparatus 190 generates a compressed audio / video signal 210 (shown generally as a schematic step 220) that is stored and / or transmitted.

[0029] The techniques to be described below relate primarily to video data compression and decompression. It will be appreciated that many of the existing techniques can be used with the video data compression techniques to be described below for audio data compression to generate a compressed audio / video signal. Accordingly, a separate discussion of audio data compression will not be provided. It will also be appreciated that the data rate associated with video data (particularly broadcast quality video data) is typically much higher than the data rate associated with audio data (whether compressed or uncompressed). It will therefore be appreciated that uncompressed audio data can accompany compressed video data to form a compressed audio / video signal. It will also be appreciated that although the present examples (as shown) relate to audio / video data, the techniques described below can be used in systems that simply process (i.e. compress, decompress, store, display and / or transmit) video data. That is, embodiments can be applied to video data compression without necessarily having to have any associated audio data processing. Figures 1 to 4

[0030] Thus, Figure 4 Examples of video capture apparatus are provided that include an image sensor and an encoding apparatus of the type to be discussed below. Thus, Figure 2 Examples of decoding apparatus of the type to be discussed below are provided, as well as displays that output decoded images.

[0031] Figure 2 And Figure 4 The combination of the image sensor 180 and the encoding apparatus 190, the decoding apparatus 110 and the display 120 to which the decoded images are output can provide a video capture apparatus.

[0032] Figure 5 And Figure 6 Storage media are schematically shown that store, for example, compressed data generated by the apparatus 20, 60, compressed data input to the apparatus 110 or storage media or stages 150, 220, Figure 6 Solid state storage media are schematically shown, such as flash memory. Note that, Figure 5 And Figure 6 Examples of non-transitory machine readable storage media that store computer software that, when executed by a computer, cause the computer to perform one or more of the methods to be discussed below can also be provided.

[0033] Thus, the above arrangements provide examples of video storage, capture, transmission or reception apparatus that embody any of the present technology.

[0034] Figure 7 Schematic diagrams of video or image data compression (encoding) and decompression (decoding) apparatus are provided for encoding and / or decoding video or images representing one or more images.

[0035] ​The controller 343 controls the overall operation of the apparatus, in particular when it comes to the compression mode, the controller 343 controls the tracking encoding process by acting as a selector to select various modes of operation, such as block size and shape, and whether or not the video data will be losslessly encoded. The controller is considered part of the image encoder or image decoder, as the case can be. Successive images of the input video signal 300 are provided to the adder 310 and the image predictor 320. The image predictor 320 will be described in more detail below. The image encoder or decoder, as the case can be, adds Figure 8 The image predictor 320 will be described in more detail below. The image encoder or decoder, as the case can be, adds Figure 8 The image predictor 320 will be described in more detail below. The image encoder or decoder, as the case can be, adds Figure 7 The image predictor 320 will be described in more detail below. The image encoder or decoder, as the case can be, adds Figure 7 The image predictor 320 will be described in more detail below. The image encoder or decoder, as the case can be, adds

[0036] The adder 310 actually performs a subtraction (negative addition) operation, since it receives the input video signal 300 on the "+" input and the output of the image predictor 320 on the "-" input, thereby subtracting the predicted image from the input image. The result is a so-called residual image signal 330 that represents the difference between the actual image and the predicted image.

[0037] One reason for generating a residual image signal is as follows. The data encoding technique to be described, i.e. the technique to be applied to the residual image signal, tends to work more efficiently when there is less "energy" in the image to be encoded. Here, the term "efficiently" means that less encoded data is generated; for a particular image quality level, it is desirable (and considered "efficient") to generate as little data as possible. The reference to "energy" in the residual image relates to the amount of information contained in the residual image. If the predicted image is identical to the true image, the difference between the two (i.e. the residual image) will contain zero information (zero energy) and will be very easy to encode into a small amount of encoded data. In general, if the prediction process is able to work reasonably well, such that the predicted image content is similar to the image content to be encoded, then it is expected that the residual image data will contain less information (less energy) than the input video, and will therefore be easier to encode into a small amount of encoded data.

[0038] Thus, encoding (using the adder 310) involves predicting an image region of an image to be encoded; and generating a residual image region from a difference between the predicted image region and a corresponding region of the image to be encoded. In combination with the techniques to be discussed below, an ordered array of data values comprises data values representing the residual image region. Decoding involves predicting an image region of an image to be decoded; generating a residual image region indicative of a difference between the predicted image region and a corresponding region of the image to be decoded; wherein an ordered array of data values comprises data values representing the residual image region; and combining the predicted image region and the residual image region.

[0039] The remainder of the apparatus, which acts as an encoder (encoding the residual or difference image), will now be described.

[0040] The residual image data 330 is provided to the transform unit or circuit 340, which generates a discrete cosine transform (DCT) representation of the blocks or regions of the residual image. DCT technology itself is well known and will not be described in detail here. It should also be noted that the use of DCT is merely an illustration of an exemplary arrangement. Other transforms that can be used include, for example, the discrete sine transform (DST). Transformations can also include sequences or cascades of individual transforms, such as an arrangement where one transform follows (whether directly or not) another. The selection of transforms can be explicitly determined and / or may depend on auxiliary information used to configure the encoder and decoder. In other examples, a so-called "transform skip" mode may be selectively used, where no transform is applied.

[0041] Therefore, in the example, the encoding and / or decoding method includes predicting an image region of the image to be encoded; and generating a residual image region based on the difference between the predicted image region and the corresponding region of the image to be encoded; wherein an ordered array of data values ​​(discussed below) includes data values ​​representing the residual image region.

[0042] The output of transform unit 340, i.e. (in this example) a set of DCT coefficients for each transformed block of image data, is provided to quantizer 350. Various quantization techniques are known in the field of video data compression, ranging from simple multiplication by a quantization scaling factor to the application of complex lookup tables under the control of quantization parameters. The overall goal is twofold. First, the quantization process reduces the number of possible values ​​for the transformed data. Second, the quantization process can increase the probability that the transformed data value is zero. Both methods enable the entropy coding process (described below) to work more efficiently when generating small amounts of compressed video data.

[0043] The scanning unit 360 applies data scanning processing. The purpose of the scanning processing is to reorder the quantized transform data in order to gather as many non-zero quantized transform coefficients as possible together, and therefore, as many zero-value coefficients as possible together. These features allow for the efficient application of so-called run-length encoding or similar techniques. Therefore, the scanning process involves selecting coefficients from the quantized transform data according to a “scan order,” specifically selecting coefficient blocks corresponding to the transformed and quantized image data blocks, (a) all coefficients are selected once as part of the scan, and (b) the scan tends to provide the desired reordering. An example scan order that may tend to give useful results is the so-called top-right diagonal scan order.

[0044] The scan order can differ between transform skip blocks and transform blocks (blocks that have undergone at least one spatial frequency transformation).

[0045] The scanned coefficients are then passed to the entropy encoder (EE) 370. Similarly, various types of entropy coding can be used. Two examples are variants of the so-called CABAC (Context Adaptive Binary Arithmetic Coding) system and the so-called CAVLC (Context Adaptive Variable Length Coding) system. Generally, CABAC is considered to offer better efficiency, and some studies have shown that, compared to CAVLC, the amount of encoded output data is reduced by 10% to 20% at comparable image quality. However, CAVLC is considered to be significantly less complex than CABAC (in terms of its implementation). Note that the scanning and entropy coding processes are shown as separate processes, but in reality, they can be combined or processed together. That is, data can be read into the entropy encoder in the order of the scan. Corresponding considerations apply to the various reverse processes described below.

[0046] The output of the entropy encoder 370, along with additional data (mentioned above and / or discussed below), such as defining how the predictor 320 generates the predicted image, whether by transforming or skipping transform compressed data, provides a compressed output video signal 380.

[0047] However, return path 390 is also provided because the operation of predictor 320 itself depends on the decompressed version of the compressed output data.

[0048] The rationale for this feature is as follows. At an appropriate stage of the decompression process (described below), a decompressed version of the residual data is generated. This decompressed residual data must be added to the prediction image to generate the output image (because the original residual data is the difference between the input image and the prediction image). To make this process comparable between the compression and decompression sides, the prediction image generated by predictor 320 should be identical during both compression and decompression processes. Of course, during decompression, the device cannot access the original input image, but only the decompressed image. Therefore, during compression, predictor 320 makes its prediction (at least for inter-image coding) based on the decompressed version of the compressed image.

[0049] The entropy encoding process performed by entropy encoder 370 is considered (in at least some examples) to be "lossless," meaning it can be reversed to obtain the exact same data as the data initially provided to entropy encoder 3700. Therefore, in this example, the return path can be implemented before the entropy encoding stage. In fact, the scanning process performed by scanning unit 360 is also considered lossless; therefore, in this embodiment, the return path 390 is from the output of quantizer 350 to the input of complementary inverse quantizer 420. Where stage-introduced loss or potential loss is present, this stage (and its reverse stage) can be included in the feedback loop formed by the return path. For example, the entropy encoding stage can, at least in principle, be lossy, for example, through techniques such as encoding bits within parity information. In this case, entropy encoding and decoding should form part of the feedback loop.

[0050] Generally, the entropy decoder 410, the inverse scan unit 400, the inverse quantizer 420, and the inverse transform unit or circuit 430 provide the corresponding inverse functions of the entropy encoder 370, the scan unit 360, the quantizer 350, and the transform unit 340; the process of decompressing the input compressed video signal will be discussed separately below.

[0051] During compression, the scan coefficients are transmitted from quantizer 350 to inverse quantizer 420 via return path 390. The inverse quantizer performs the inverse operation of scan unit 360. The inverse quantization and inverse transformation processes are performed by units 420 and 430 to generate compressed-decompressed residual image signal 440.

[0052] Image signal 440 is added to the output of predictor 320 at adder 450 to generate reconstructed output image 460 (although it may undergo so-called loop filtering and / or other filtering before the output—see below). This forms an input to image predictor 320, as described below.

[0053] Now we turn to the decoding process applied to the decompressed received video signal 470, which is provided to the entropy decoder 410 and from the entropy decoder 410 to a chain of inverse scan unit 400, inverse quantizer 420, and inverse transform unit 430, and then added by adder 450 to the output of image predictor 320. Thus, on the decoder side, the decoder reconstructs a version of the residual image and then applies it (via adder 450) to the predicted version of the image (block-by-block) to decode each block. Simply put, the output 460 of adder 450 forms the output decompressed video signal 480 (subject to the filtering process discussed below). In practice, additional filtering (e.g., by...) can optionally be applied before the output signal. Figure 8 The loop filter 565 shown is used, but in order to... Figure 7 The clarity of higher-level imagesFigure 7 omitted).

[0054] Figure 7 and Figure 8 The device can function as either a compression (encoding) device or a decompression (decoding) device. The functions of the two types of devices largely overlap. In decompression mode, the scan unit 360 and the entropy encoder 370 are not used, and the operation of the predictor 320 (described in detail below) and other units follows the mode and parameter information contained in the received compressed bitstream, rather than following the information itself that generated it.

[0055] Figure 8 The generation of the predicted image is illustrated schematically, particularly the operation of the image predictor 320.

[0056] There are two basic prediction modes performed by the image predictor 320: so-called intra-image prediction and so-called inter-image or motion compensation (MC) prediction. On the encoder side, each involves detecting the prediction direction with respect to the current block to be predicted and generating a predicted block of samples based on other samples (in the same (intra) or another (inter) image). The difference between the predicted block and the actual block is encoded or applied by means of unit 310 or 450 to encode or decode the block respectively.

[0057] (At the decoder, or on the reverse decoding side of the encoder, the detection of the predicted direction can be in response to data associated with the encoder's encoded data, indicating which direction was used at the encoder. Alternatively, the detection can be in response to the same factor that makes the decision at the encoder.)

[0058] Intra-image prediction predicts the content of blocks or regions of an image based on data from within the same image. This corresponds to so-called I-frame coding in other video compression techniques. However, unlike I-frame coding, which involves encoding the entire image by intra-coding, in this embodiment, a choice can be made between intra-coding and inter-coding on a block-by-block basis, although in other embodiments the choice is still made on an image-by-image basis.

[0059] Motion-compensated prediction is an example of inter-image prediction, and it utilizes motion information that attempts to define a source of image details to be encoded in the current image in another neighboring or nearby image. Therefore, in an ideal example, the contents of image data blocks in the predicted image can be very simply encoded as references (motion vectors) pointing to corresponding blocks at the same or slightly different locations in neighboring images.

[0060] A technique called “block copying” prediction is in some respects a hybrid of the two, as it uses vectors to indicate sample blocks in the same image that are offset from the current predicted block and should be copied to form the current predicted block.

[0061] return Figure 8 This illustrates two image prediction arrangements (corresponding to intra-image and inter-image predictions), the results of which are selected by multiplexer 500 under the control of mode signal 510 (e.g., from controller 343) to provide blocks of predicted images to adders 310 and 450, and this selection is signaled to the decoder within the encoded output data stream. In this case, image energy can be detected, for example, by performing an attempt to subtract the areas of the two versions of the predicted image from the input image, square the values ​​of each pixel in the difference image, sum the squared values, and identify which of the two versions produces the lower mean square value of the difference image associated with that image region. In other examples, an attempt to encode can be performed for each selected or potential selection, and then a choice can be made in one or both aspects of the number of bits required for encoding and image distortion, based on the cost of each potential selection.

[0062] In the intra-encoding system, the actual prediction is based on the image blocks received as part of signal 460 (filtered by loop filtering; see below), that is, the prediction is based on the encoded-decoded image blocks so that the exact same prediction is performed at the decompression device. However, data can be derived from the input video signal 300 via the intra-mode selector 520 to control the operation of the intra-image predictor 530.

[0063] For inter-image prediction, the motion compensation (MC) predictor 540 uses motion information such as motion vectors derived from the input video signal 300 by the motion estimator 550. These motion vectors are applied by the motion compensation predictor 840 to a processed version of the reconstructed image 460 to generate inter-image predicted blocks.

[0064] Therefore, units 530 and 540 (operating together with estimator 550) each act as detectors to detect the prediction direction of the current block to be predicted, and act as generators to generate prediction sample blocks (forming part of the predictions passed to units 310 and 450) based on other samples defined by the prediction direction.

[0065] The processing applied to signal 460 will now be described.

[0066] First, the signal can be filtered by a so-called loop filter 565. Various types of loop filters can be used. One technique involves applying a “deblocking” filter to remove or at least tend to reduce the effects of block-based processing and subsequent operations performed by the transform unit 340. Another technique involves applying a so-called sample adaptive offset (SAO) filter. Generally, in a sample adaptive offset filter, filter parameter data (derived at the encoder and transmitted to the decoder) defines one or more offsets that will be selectively combined by the sample adaptive offset filter with a given intermediate video sample (a sample of signal 460) according to: (i) the value of the given intermediate video sample; or (ii) one or more intermediate video samples having a predetermined spatial relationship with the given intermediate video sample.

[0067] Additionally, an adaptive loop filter can optionally be applied using coefficients derived from processing the reconstructed signal 460 and the input video signal 300. An adaptive loop filter is a filter that uses known techniques to apply adaptive filter coefficients to the data to be filtered. That is, the filter coefficients can vary according to various factors. The data defining which filter coefficients to use is included as part of the encoded output data stream.

[0068] The techniques discussed below involve processing parameter data related to filter operation. Actual filtering operations (e.g., SAO filtering) can utilize other known techniques.

[0069] When the device operates as a decompression unit, the filtered output from the loop filter unit 565 effectively forms the output video signal 480. This signal is also buffered in one or more image or frame memories 570; the storage of consecutive images is a requirement of motion compensation prediction processing, particularly for the generation of motion vectors. To save storage space, the images stored in the image memory 570 can be saved in compressed form and then decompressed for use in generating motion vectors. For this purpose, any known compression / decompression system can be used. The stored images can be passed to an interpolation filter 580, which generates a higher-resolution version of the stored images; in this example, intermediate samples (subsamples) are generated such that the resolution of the interpolated image output by the interpolation filter 580 is four times (in each dimension) that of the image stored in the image memory 570 for the 4:2:0 luma channel and eight times (in each dimension) that of the image stored in the image memory 570 for the 4:2:0 chroma channel. The interpolated image is passed as input to the motion estimator 550 and the motion compensation predictor 540.

[0070] The method by which images are segmented for compression processing will now be described. At a basic level, the image to be compressed is considered as an array of sample blocks or regions. Images can be segmented into these blocks or regions using a decision tree, as described in SERIES H:AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services – Coding of moving video High efficiency video coding Recommendation ITU-TH.265 12 / 2016. Also: High Efficiency Video Coding (HEVC) Algorithms and Architectures, chapter 3, editors: Madhukar Budagavi, Gary J. Sullivan, Vivienne Sze; ISBN 978-3-319-06894-7; 2014, the entirety of which is incorporated herein by reference. [1] Further background information is provided in “Versatile Video Coding (Draft 8)”, JVET-Q2001-vE, by B. Bross, J. Chen, S. Liu and YK. Wang, the full contents of which are incorporated herein by reference.

[0071] In some examples, the resulting blocks or regions have dimensions, and in some cases, shapes, which, with the help of a decision tree, can often follow the configuration of image features within the image. This in itself can allow for improved encoding efficiency, as samples representing or following similar image features will tend to be grouped together through this arrangement. In some examples, square blocks or regions of different sizes (e.g., 4x4 samples of blocks up to 64x64 or larger) are available. In other example arrangements, blocks or regions of different shapes can be used, such as rectangular blocks (e.g., vertical or horizontally oriented). Consider other non-square and non-rectangular blocks. The result of dividing the image into such blocks or regions is (at least in this example) assigning each sample of the image to one and only one such block or region.

[0072] Encoded image buffer

[0073] Video decoding specifications (and, indirectly, the corresponding encoders) can be defined as including a so-called coded picture buffer (CPB). On the decoder side, the input video stream is stored in the CPB in real time and read from the CPB for decoding. These specifications assume that the entire picture can be read from the CPB in a single (theoretically instantaneous) operation. On the encoder side, encoded data can be similarly stored in the CPB (theoretically at least as a single instantaneous operation of writing the entire coded picture) and then output to the output coded video stream. However, the CPB is defined on the decoder side.

[0074] The CPB itself can be defined by various aspects, including the rate at which encoded data enters the CPB, the size of the CPB itself, and any potential latency applied to removing data from the CPB (which in turn defines the time required to fill the CPB so that the entire image can be removed as described above).

[0075] These parameters are crucial for avoiding CPB overfilling (insufficient space) and CPB underfilling (insufficient data to provide for the next stage of processing). An example of using CPB will be discussed below.

[0076] Parameter set and encoding level

[0077] When video data is encoded using the techniques described above for subsequent decoding, it is appropriate for the encoding side to transmit some parameters of the encoding process to the final decoding side. Considering that these encoding parameters are needed whenever the encoded video data is decoded, it is useful to associate these parameters with the encoded video data stream itself by embedding the encoding parameters as a so-called parameter set within the encoded video data stream itself, for example (although not necessarily exclusively, since the encoded video data stream can be transmitted "out of band" through a separate transmission channel).

[0078] Parameter sets can be represented as a hierarchical information structure, such as a Video Parameter Set (VPS), Sequence Parameter Set (SPS), and Picture Parameter Set (PPS). A PPS is expected to appear once in each picture and contains information related to all coded slices within that picture. SPSs appear less frequently (once per picture sequence), and VPSs also appear less frequently. More frequently occurring parameter sets (such as PPSs) can be implemented as references to previously coded instances of that parameter set to avoid the cost of re-encoding. Each coded picture slice references a single active PPS, SPS, and VPS to provide information for decoding that slice. Specifically, each slice header may contain a PPS identifier that references a PPS, which in turn references an SPS, and the SPS in turn references a VPS.

[0079] Within these parameter sets, SPS contains example information relevant to the following discussion, namely, data defining the so-called configuration files, layers, and encoding levels to be used.

[0080] The configuration file defines a set of decoding tools or functions to be used. Example configuration files include a "main configuration file" associated with 4:2:0 video at 8 bits, and a "main 10 configuration file" that allows 10-bit resolution and other extensions associated with the main configuration file.

[0081] The encoding level imposes limitations on issues such as maximum sampling rate and image size. This layer imposes a maximum data rate.

[0082] The Joint Video Experts Group (JVET) Universal Video Coding (VVC) proposal, as defined in the aforementioned specification JVET-Q2001-vE (at the submission date), defines different levels from 1 to 6.2.

[0083] Example Implementation

[0084] Example embodiments will now be described with reference to the accompanying drawings.

[0085] Figure 9 The use of video parameter sets and sequence parameter sets is illustrated schematically, as described above. Specifically, these form part of the aforementioned hierarchical structure of parameter sets, such that multiple sequence parameter sets 900, 910, 920 can reference video parameter set 930, and are subsequently referenced by corresponding sequences 902, 912, 922. In the example embodiment, level information applicable to the respective sequences is provided in the sequence parameter sets.

[0086] However, in other embodiments, it should be understood that level information may be provided in different forms or with different sets of parameters.

[0087] Similarly, although Figure 9 The diagram illustrates a sequence parameter set set as part of the overall video data stream 940, but the sequence parameter set (or other data structures carrying level information) can be provided by a separate communication channel. In either case, the level information is associated with the video data stream 940.

[0088] Example Operation - Decoder

[0089] Figure 10 This schematically illustrates a configuration to receive input (encoded) video data stream 1000 and uses the reference above. Figure 7 This discussion covers various aspects of the decoding apparatus, including the decoder 1020, which generates and outputs the decoded video data stream 1010. For clarity, Figure 7 The control circuit or controller 343 is drawn separately from the rest of the decoder 1020.

[0090] Within the functionality of the controller or control circuitry 343, the parameter set (PS) detector 1030 detects various parameter sets, including VPS, SPS, and PPS, from appropriate fields of the input video data stream 1000. The parameter set detector 1030 derives information from the parameter sets, including the levels described above. This information is then transmitted to the remainder of the control circuitry 343. Note that the parameter set detector 1030 can decode this level, or the encoded level can simply be provided to the control circuitry 344 for decoding.

[0091] The control circuit 343 also responds to one or more decoder parameters 1040, which at least define, for example, the level that decoder 1020 is capable of decoding.

[0092] For a given or current input video data stream 1000, the control circuit 343 detects whether the decoder 1020 is capable of decoding the input video data stream and controls the decoder 1020 accordingly. The control circuit 343 can also provide various other operating parameters to the decoder 1020 in response to information obtained from the parameter set detected by the parameter set detector 1030.

[0093] Figure 10 It is also shown that the input video data stream 1000 is buffered by the encoded picture buffer (CPB) 1025 before it is provided to the decoder 1020 for decoding. The control circuit 343 controls the parameters of the CPB 1025 according to the basic parameters 1040 of the decoder and the parameters derived from the parameter set decoder 1030.

[0094] therefore, Figure 10 An example device is provided, including:

[0095] Video data decoder 1020; and

[0096] Encoded picture buffer 1025 buffers a continuous portion of the input video data stream and provides the continuous portion to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size.

[0097] The video data decoder responds to parameter data associated with the input video data stream, which indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size.

[0098] Example Operation - Encoder

[0099] In a similar way, Figure 11 The various aspects of the encoding device, including those referenced above, are schematically illustrated.Figure 7 The encoder 1100 is discussed. For clarity, the encoder's control circuitry 343 is drawn separately. The encoder acts on the input video data stream 1110 to generate and output an encoded video data stream 1120 under the control of the control circuitry 343, which in turn responds to encoding parameters 1130 that define the encoding level to be applied.

[0100] The control circuit 343 also includes a control parameter set generator 1140, which generates a parameter set including, for example, VPS, SPS, and PPS to be included in the output encoded video data stream, wherein the SPS carries level information encoded as described above.

[0101] In a similar manner to the above, Figure 11 It also shows the use of an encoded picture buffer (CPB) 1125 to buffer the encoded video data stream 1120 generated by the encoder 1100. The control circuit 343 controls the parameters of the CPB 1125 according to the encoding parameters 1130, and these parameters are transmitted by the parameter set generator 1140 to the output encoded video data stream 1120 (and thus to the final decoding stage).

[0102] This provides examples of devices, including:

[0103] Video data encoder 1100; and

[0104] Encoded picture buffer 1125 buffers a continuous portion of the current output video data stream generated by the video data encoder, and the encoded picture buffer has an encoded picture buffer size;

[0105] The video data encoder responds to parameter data associated with the output video data stream, which indicates a coding level selected from multiple coding levels for a given output video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size.

[0106] The embodiments of this disclosure involve potential changes to the parameters of the current VVC specification (as applicable at the time of submission) to ensure that the buffer can always store the full image when compressed at the minimum compression ratio (MinCR). Potential changes include the maximum encoded image buffer (CPB) size and the minimum compression scaling factor (MinCRScalingFactor).

[0107] Example background

[0108] Table A.1 in the current specification defines the maximum encoded picture buffer (CPB) size, MaxCPB, for each level. It is required that all encoded pictures must be stored within the CPB and can be automatically retrieved from Appendix C1 of this specification at least momentarily.

[0109] In addition, Table A.2 of the current specification defines the minimum compression ratio base (MinCRBase), which, together with MinCRScalingFactor, allows the calculation of the minimum compression ratio (MinCR). MinCR is used to guarantee that the image is compressed by at least the specified amount.

[0110] However, MinCR is not always a limiting factor. The example embodiments discussed below suggest removing MinCR from the specification or adjusting the values ​​in Appendix A to make MinCR useful again.

[0111] For example, as the analysis will be discussed below, an 8K image encoded with the minimum compression ratio MinCR using the main 10 profile, level 6, and main layer cannot be stored in the CPB; the same applies to multiple levels for the main 4:4:410 profile.

[0112] Figure 12 Table A.1, which relates to general layer and level limits in the current specification, is reproduced here. The level is indicated by its level number in the left column. The second column represents the maximum brightness (or luminance) image size. Following the definition of the maximum CPB size (for main layers and higher layers), scaling is performed using the scaling factor, the maximum number of slices, the maximum number of tile rows, and the maximum number of tile columns, as shown in the figure.

[0113] Figure 13 Table A.2 of the current specification is reproduced, which details the maximum luminance sampling rate for each level, the maximum bit rate for the primary and higher layers, and the minimum compression ratio base for the primary and higher layers.

[0114] Figure 14 The various scaling factors in Table A.3 are reproduced.

[0115] Figure 15 The table displays the maximum image size, maximum CPB size, maximum encoded image size at MinCR, and minimum number of images in the main 10 configuration file. Note that columns two, four, and six are from Table A.1 or Table A.2 in this specification; other fields are derived from these, CpbVclFactor, and MinCRScaleFactor. Figure 14 ).

[0116] Note that the column labeled “Example Maximum Luminance Size” provides only an example of a luminance image configuration that conforms to the sample size defined by the corresponding maximum luminance image size and the aspect of the ratio constraints imposed by other parts of the current specification; this column is for illustrative purposes only and does not constitute part of this specification.

[0117] Analysis of this information reveals that the last column provides the minimum number of encoded images that can be stored in the CPB, which assumes a maximum CPB size defined by the specification and a minimum compression ratio defined by MinCRBase and MinCRScaleFactor.

[0118] about Figure 15 As can be seen, under these conditions, the row corresponding to level 6 allows for the storage of less than one encoded image in the CPB.

[0119] Figure 16 The relevant information for the main 444 10 configuration file is displayed, and it can be seen that the problem occurs at levels 1, 3, 3.1, 4, 5, and 6.

[0120] Notice, Figure 15 and Figure 16 Only the main layer is displayed because the same problem does not occur at higher levels.

[0121] Features of Example Implementation

[0122] It is recommended to remove the MinCR constraint (since it is usually unnecessary), or adjust the value used to derive the CPB dimensions so that MinCR becomes always relevant.

[0123] Example 1 – Remove or ignore MinCR

[0124] In this example, if the minimum compression ratio specification makes it possible to ignore all other current or general parameters, the encoder and decoder control circuit 343 will not be able to preserve the entire encoded image if the maximum CPB size is not specified.

[0125] Therefore, this provides an example in which the video data encoder is configured to generate the current output video data stream by applying a compression ratio greater than that defined by the minimum compression ratio, when the minimum compression ratio defined by the encoding level applicable to the current output video stream makes the encoded picture buffer, defined by the size of the encoded picture buffer, insufficient to buffer the number of bits required to represent the picture at the maximum luminance picture size when encoded according to the minimum compression ratio.

[0126] Example 2 - Modified Maximum CPB Size

[0127] Figure 17 The table shows the maximum CPB size after the level 6 modification. By allowing a larger maximum CPB size at level 6, the system is now able to store at least one encoded image in the CPB under the most challenging combination of conditions mentioned above (minimum compression ratio, maximum encoded image size).

[0128] Therefore, this provides an example where, for each of the multiple encoding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0129] Example 3 - Adjusting the minimum compression ratio to 4:4:4 10

[0130] refer to Figure 18 As mentioned above, measures are taken for this configuration file that involves adjusting MinCRScaleFactor (equal to 0.75) and the same modifications to MaxCPB at level 6.

[0131] Therefore, this provides an example where, for each of a plurality of encoding levels, the minimum compression ratio makes the encoded image buffer size define an encoded image buffer that is sufficient to buffer the number of bits required to represent an image at the maximum luminance image size when encoded according to the minimum compression ratio.

[0132] Example 4 - CpbVclFactor

[0133] Table A.3 specifies that the CpbVclFactor for main 444 10 is 2.5 times that for main 10. To keep the CpbVclFactor consistent with the FormatCapabilityFactor, this example recommends changing the CpbVclFactor used for main 444 10 to twice the CpbVclFactor used for main 10. It is also recommended to keep the MinCRScaleFactor for both profiles at 1.0. These aspects are as follows... Figure 19 As shown.

[0134] As background, the format performance factor defines the number of bytes per pixel in the source, so 4:4:4 is twice that of 4:2:0. Using the same ratio in compressed data seems more concise than the currently specified 2.5. This is based on the assumption that the compressed data is compressed just as well, which is possible, at least without excessive chroma noise.

[0135] For the HEVC master configuration file (8-bit), CpbVclFactor is 1000. However, for the HEVC master 10 configuration file, CpbVclFactor does not increase when it can be argued that it should have. VVC inherits these numbers from HEVC.

[0136] If the factor is reduced by 444, the MinCR used for both profiles can also be properly aligned so that it still fits the full picture in CPB.

[0137] Figure 20 The table shows the effects of the suggested modifications in this example.

[0138] Further examples

[0139] The following table provides another example embodiment and can be considered as an alternative to the corresponding table provided in the accompanying drawings. Refer to Table 135 in Appendix 4.1 of JVET-T2001-v1 (the contents of which are incorporated herein by reference) from the 20th JVET meeting in October 2020:

[0140] These are examples of similar explanations. Figure 15 and Figure 16 The example shown, and other examples of the above situations, namely, in the main 10 configuration file, the line corresponding to level 6 allows for the storage of fewer than one encoded image in the CPB under these conditions.

[0141]

[0142]

[0143] The table below illustrates a similar situation in the main 444 10 configuration file, showing that the problem occurs at levels 1, 3, 3.1, 4, 5, and 6.

[0144]

[0145] The following table provides similar information. Figure 17 and Figure 18 Suggestions for resolving these issues (Main 10 and Main 444 10 respectively):

[0146]

[0147]

[0148]

[0149] The table below provides further suggestions for resolving these issues, similar to... Figure 17 and Figure 18 (respectively, Lord 10 and Lord 44410):

[0150]

[0151]

[0152]

[0153] Each of these alternative embodiments (in fact, each of the embodiments described above) can be considered to be within the scope of the appended claims.

[0154] Encoded video data

[0155] Video data encoded using any of the techniques disclosed herein is also considered to represent embodiments of this disclosure.

[0156] Summary of methods

[0157] Figure 21 It is a schematic flowchart illustrating the method, including:

[0158] The input video data is buffered in the encoded picture buffer (in step 2100) to buffer consecutive portions of the input video data stream, and these consecutive portions are provided to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size; and

[0159] In response to the decoding of a portion of the input video data associated with the input video data stream (in step 2110), the parameter data indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, the minimum compression ratio, and the coding picture buffer size;

[0160] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0161] Figure 22 This is a schematic flowchart illustrating a method that includes:

[0162] The input video data is buffered in the encoded picture buffer (in step 2200) to buffer a continuous portion of the input video data stream and provide a portion to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size.

[0163] In response to parameter data associated with the input video data stream (in step 2210), the output video data stream is decoded. The parameter data indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, the minimum compression ratio, and the coding picture buffer size.

[0164] Specifically, for each of the multiple coding levels, a coding image buffer is defined at the minimum compression ratio such that the coding image buffer size is sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when coding according to the minimum compression ratio.

[0165] Figure 23 This is a schematic flowchart illustrating a method, which includes:

[0166] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded (in step 2300) to generate the output encoded video stream. The parameter data indicates the encoding level selected from multiple encoding levels for a given output encoded video data stream, each level defining at least the maximum maximum luma picture size, minimum compression ratio, and maximum value of the encoded picture buffer size; and

[0167] The encoded output video data stream is buffered (in step 2310) in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, the encoded picture buffer having an encoded picture buffer size;

[0168] Wherein, when the minimum compression ratio defined by the encoding level applicable to the current output video stream makes the encoded image buffer size defined by the encoded image buffer size insufficient to buffer the number of bits required to represent the image at the maximum luminance image size, the encoding step includes generating the output encoded video data stream by applying a compression ratio greater than that defined by the minimum compression ratio.

[0169] Figure 24 It is a schematic flowchart illustrating the method, including:

[0170] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded (in step 2400) to generate the output encoded video stream. The parameter data indicates, for a given output encoded video data stream, a coding level selected from multiple coding levels, each level defining at least the maximum maximum luma picture size, minimum compression ratio, and maximum value of the encoded picture buffer size; and

[0171] The encoded output video data stream is buffered (in step 2410) in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, the encoded picture buffer having an encoded picture buffer size;

[0172] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0173] Figure 25 It is a schematic flowchart illustrating the method, including:

[0174] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded (in step 2500) to generate the output encoded video data stream. The parameter data indicates, for a given output encoded video stream, a coding level selected from multiple coding levels, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and encoded picture buffer size; and

[0175] The encoded output video data stream is buffered (in step 2510) in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, the encoded picture buffer having an encoded picture buffer size;

[0176] Specifically, for each of the multiple coding levels, when coding according to the minimum compression ratio, the minimum compression ratio makes the coded image buffer size define a coded image buffer sufficient to buffer the number of bits required to represent the image at the maximum luminance image size.

[0177] Since embodiments of this disclosure have been described as being implemented at least in part by a data processing apparatus controlled by software, it should be understood that non-transient machine-readable media carrying such software, such as optical discs, magnetic disks, semiconductor memories, etc., are also considered to represent embodiments of this disclosure. Similarly, data signals including encoded data generated according to the methods described above (whether or not embodied on a non-transient machine-readable medium) are also considered to represent embodiments of this disclosure.

[0178] Based on the foregoing teachings, many modifications and variations of this disclosure are possible. Therefore, it should be understood that this technology may be practiced within the scope of the appended provisions, and not as specifically described herein.

[0179] It should be understood that, for clarity, the above description has referenced various functional units, circuits, and / or processors in the embodiments. However, it will be apparent that any suitable functional distribution among the various functional units, circuits, and / or processors may be used without departing from the embodiments.

[0180] The described embodiments can be implemented in any suitable form, including hardware, software, firmware, or any combination thereof. The described embodiments can optionally be implemented, at least in part, as computer software running on one or more data processors and / or digital signal processors. Elements and components of any embodiment can be implemented physically, functionally, and logically in any suitable manner. In practice, functionality can be implemented in a single unit, multiple units, or as part of other functional units. Therefore, the disclosed embodiments can be implemented in a single unit or physically and functionally distributed among different units, circuits, and / or processors.

[0181] Although this disclosure has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms described herein. Furthermore, while it may appear that features can be described in conjunction with specific embodiments, those skilled in the art will recognize that the various features of the described embodiments can be combined in any manner suitable for implementing the technology.

[0182] The aspects and characteristics are defined by the following numbered clauses:

[0183] 1. An apparatus comprising:

[0184] Frequency data decoder; and

[0185] An encoded picture buffer buffers a continuous portion of the input video data stream and provides a portion to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size.

[0186] The video data decoder responds to parameter data associated with the input video data stream, which indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size;

[0187] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0188] 2. The apparatus according to Clause 1, wherein a portion is a portion representing data of the entire image.

[0189] 3. A video storage, capture, transmission or reception apparatus, including the apparatus of Clause 1.

[0190] 4. A method comprising:

[0191] The input video data is buffered in an encoded picture buffer to buffer continuous portions of the input video data stream, and a portion is provided to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size; and

[0192] A portion of the input video data stream is decoded in response to parameter data associated with the input video data stream. The parameter data indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size.

[0193] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0194] 5. A computer software that, when executed by a computer, causes the computer to perform the method described in Clause 4.

[0195] 6. A machine-readable non-transient storage medium storing the computer software of Clause 5.

[0196] 7. An apparatus comprising:

[0197] Video data decoder; and

[0198] An encoded picture buffer buffers a continuous portion of the input video data stream and provides a portion to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size.

[0199] The video data decoder responds to parameter data associated with the input video data stream, which indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size;

[0200] For each of the multiple coding levels, the minimum compression ratio makes the coded image buffer size define the coded image buffer size to be sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0201] 8. The apparatus according to Clause 7, wherein a portion is a portion representing data of the entire picture.

[0202] 9. A video storage, capture, transmission or reception apparatus, including the apparatus of Clause 7.

[0203] 10. A method comprising:

[0204] The input video data is buffered in an encoded picture buffer to buffer continuous portions of the input video data stream, and a portion is provided to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size; and

[0205] In response to parameter data associated with the input video data stream, the input video data stream is decoded. The parameter data indicates a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size.

[0206] For each of the multiple coding levels, the minimum compression ratio makes the coded image buffer size define the coded image buffer size to be sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0207] 11. A computer software that, when executed by a computer, causes the computer to perform clause 10.

[0208] 12. A machine-readable non-transient storage medium storing the computer software of Clause 11.

[0209] 13. An apparatus comprising:

[0210] Video data encoder; and

[0211] An encoded picture buffer buffers a continuous portion of the current output video data stream generated by a video data encoder. The encoded picture buffer has an encoded picture buffer size.

[0212] The video data encoder responds to parameter data associated with the output video data stream, which indicates a coding level selected from multiple coding levels for a given output video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size;

[0213] Specifically, when the minimum compression ratio defined by the encoding level applicable to the current output video stream makes the encoded picture buffer, defined by the size of the encoded picture buffer, insufficient to buffer the number of bits required to represent the picture at the maximum luminance picture size when encoding according to the minimum compression ratio, the video data encoder is configured to generate the current output video data stream by applying a compression ratio greater than that defined by the minimum compression ratio.

[0214] 14. The apparatus according to Clause 13, wherein a portion is a portion representing data of the entire picture.

[0215] 15. A video storage, capture, transmission or reception apparatus, including the apparatus pursuant to Clause 13.

[0216] 16. A method comprising:

[0217] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream. The parameter data indicates a coding level selected from multiple coding levels for a given output encoded video data stream, each level defining at least the maximum maximum luma picture size, minimum compression ratio, and maximum value of the encoded picture buffer size; and

[0218] The output encoded video data stream is buffered in the encoded picture buffer, which is configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, and the encoded picture buffer has an encoded picture buffer size.

[0219] Wherein, when the minimum compression ratio defined by the encoding level applicable to the current output video stream makes the encoded picture buffer defined by the encoded picture buffer size insufficient to buffer the number of bits required to represent the picture at the maximum luminance picture size when encoding according to the minimum compression ratio, the encoding step includes generating the output encoded video data stream by applying a compression ratio greater than the compression ratio defined by the minimum compression ratio.

[0220] 17. A computer software that, when executed by a computer, causes the computer to perform clause 16.

[0221] 18. A machine-readable non-transient storage medium storing the computer software of Clause 17.

[0222] 19. An apparatus comprising:

[0223] Video data encoder; and

[0224] An encoded picture buffer buffers a continuous portion of the current output video data stream generated by a video data encoder. The encoded picture buffer has an encoded picture buffer size.

[0225] The video data encoder responds to parameter data associated with the output video data stream, which indicates a coding level selected from multiple coding levels for a given output video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size;

[0226] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0227] 20. The apparatus according to Clause 19, wherein a portion is a portion representing data of the entire picture.

[0228] 21. A video storage, capture, transmission or reception apparatus, including the apparatus of clause 19.

[0229] 22. A method comprising:

[0230] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream. The parameter data indicates a coding level selected from multiple coding levels for a given output encoded video data stream, each level defining at least the maximum maximum luma picture size, minimum compression ratio, and maximum value of the encoded picture buffer size; and

[0231] The output encoded video data stream is buffered in the encoded picture buffer, which is configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, and the encoded picture buffer has an encoded picture buffer size.

[0232] For each of the multiple coding levels, the maximum value of the encoded image buffer size is greater than or equal to the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0233] 23. A computer software that, when executed by a computer, causes the computer to perform clause 22.

[0234] 24. A machine-readable non-transient storage medium storing the computer software of Clause 23.

[0235] 25. An apparatus comprising:

[0236] Video data encoder; and

[0237] An encoded picture buffer buffers a continuous portion of the current output video data stream generated by a video data encoder. The encoded picture buffer has an encoded picture buffer size.

[0238] The video data encoder responds to parameter data associated with the output video data stream, which indicates a coding level selected from multiple coding levels for a given output video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and coding picture buffer size;

[0239] For each of the multiple coding levels, the minimum compression ratio makes the coded image buffer size define the coded image buffer to be sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0240] 26. The apparatus according to Clause 25, wherein a portion is a portion representing data of the entire picture.

[0241] 27. A means of storing, capturing, transmitting or receiving video, including the means of clause 25.

[0242] 28. A method comprising:

[0243] In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream. The parameter data indicates a coding level selected from multiple coding levels for a given output encoded video data stream, each level defining at least the maximum maximum luma picture size, minimum compression ratio, and maximum value of the encoded picture buffer size; and

[0244] The output encoded video data stream is buffered in the encoded picture buffer, which is configured to buffer consecutive portions of the output encoded video data stream generated by the encoding step, and the encoded picture buffer has an encoded picture buffer size.

[0245] For each of the multiple coding levels, the minimum compression ratio makes the coded image buffer size define the coded image buffer size to be sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio.

[0246] 29. A computer software that, when executed by a computer, causes the computer to perform clause 28.

[0247] 30. A machine-readable non-transient storage medium storing computer software of Clause 29.

Claims

1. An apparatus for decoding video encoded according to a common video coding scheme, the apparatus comprising: Video data decoder; as well as An encoded image buffer buffers a continuous portion of the input video data stream of the main layer and provides a portion to the video data decoder for decoding. The encoded image buffer has an encoded image buffer size. The video data decoder responds to parameter data associated with the input video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given input video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the maximum value of the coding image buffer size is greater than or equal to the number of bits required to represent the image with the maximum luminance image size when coding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression ratio factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

2. The apparatus according to claim 1, wherein, The continuous portion is the part that represents the data of the entire image.

3. A video storage, capture, transmission, or reception apparatus, comprising the apparatus according to claim 1.

4. A method for decoding video encoded according to a common video coding scheme, the method comprising: The input video data of the main layer is buffered in the encoded picture buffer to buffer continuous portions of the input video data stream, and a portion is provided to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size. and A portion of the input video data stream is decoded in response to parameter data associated with the input video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given input video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the maximum value of the coding image buffer size is greater than or equal to the number of bits required to represent the image with the maximum luminance image size when coding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression ratio factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

5. A machine-readable non-transient storage medium storing computer software, which, when executed by a computer, causes the computer to perform the method according to claim 4.

6. An apparatus for decoding video according to a common video encoding scheme, the apparatus comprising: Video data decoder; as well as An encoded image buffer buffers a continuous portion of the input video data stream of the main layer and provides a portion to the video data decoder for decoding. The encoded image buffer has an encoded image buffer size. The video data decoder responds to parameter data associated with the input video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given input video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the minimum compression ratio causes the coding image buffer size to define the coding image buffer sufficiently to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression scaling factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

7. The apparatus according to claim 6, wherein, The continuous portion is the part that represents the data of the entire image.

8. A video storage, capture, transmission, or reception apparatus, comprising the apparatus according to claim 6.

9. A method for decoding video according to a common video coding scheme, the method comprising: The input video data of the main layer is buffered in the encoded picture buffer to buffer continuous portions of the input video data stream, and a portion is provided to the video data decoder for decoding. The encoded picture buffer has an encoded picture buffer size. and In response to parameter data associated with the input video data stream, the input video data stream is decoded, the parameter data indicating a coding level selected from multiple coding levels for a given input video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the minimum compression ratio causes the coding image buffer size to define the coding image buffer sufficiently to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression scaling factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

10. A machine-readable non-transient storage medium storing computer software, which, when executed by a computer, causes the computer to perform the method according to claim 9.

11. An apparatus for encoding video according to a generic video coding scheme, the apparatus comprising: Video data encoder; as well as An encoded picture buffer buffers a continuous portion of the current output video data stream of the main layer generated by the video data encoder, the encoded picture buffer having an encoded picture buffer size; The video data encoder responds to parameter data associated with the output video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, when the minimum compression ratio defined by the encoding level of the main layer applicable to the current output video stream makes the encoded picture buffer, defined by the size of the encoded picture buffer, insufficient to buffer the number of bits required to represent the picture at the maximum luminance picture size when encoding according to the minimum compression ratio, the video data encoder is configured to generate the current output video data stream by applying a compression ratio greater than that defined by the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio base and the minimum compression scaling factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

12. The apparatus according to claim 11, wherein, The continuous portion is the part that represents the data of the entire image.

13. A video storage, capture, transmission, or reception apparatus, comprising the apparatus according to claim 11.

14. A method for encoding video according to a generic video coding scheme, the method comprising: In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output encoded video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and encoded picture buffer size; and The output encoded video data stream of the main layer is buffered in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated through the encoding step, the encoded picture buffer having an encoded picture buffer size; Wherein, when the minimum compression ratio defined by the encoding level applicable to the main layer of the current output video stream makes the encoded picture buffer, defined by the size of the encoded picture buffer, insufficient to buffer the number of bits required to represent the picture at the maximum luminance picture size when encoding according to the minimum compression ratio, the encoding step includes generating the output encoded video data stream by applying a compression ratio greater than that defined by the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio base and the minimum compression scaling factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

15. A machine-readable non-transient storage medium storing computer software, which, when executed by a computer, causes the computer to perform the method according to claim 14.

16. An apparatus for encoding video according to a generic video coding scheme, the apparatus comprising: Video data encoder; as well as An encoded picture buffer buffers a continuous portion of the current output video data stream of the main layer generated by the video data encoder, the encoded picture buffer having an encoded picture buffer size; The video data encoder responds to parameter data associated with the output video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the maximum value of the coding image buffer size is greater than or equal to the number of bits required to represent the image with the maximum luminance image size when coding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression ratio factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

17. The apparatus according to claim 16, wherein, The continuous portion is the part that represents the data of the entire image.

18. A video storage, capture, transmission, or reception apparatus, comprising the apparatus according to claim 16.

19. A method for encoding video according to a generic video coding scheme, the method comprising: In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output encoded video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and encoded picture buffer size; and The output encoded video data stream of the main layer is buffered in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated through the encoding step, the encoded picture buffer having an encoded picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the maximum value of the coding image buffer size is greater than or equal to the number of bits required to represent the image with the maximum luminance image size when coding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression ratio factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

20. A machine-readable non-transient storage medium storing computer software, which, when executed by a computer, causes the computer to perform the method according to claim 19.

21. An apparatus for encoding video according to a generic video coding scheme, the apparatus comprising: Video data encoder; as well as An encoded picture buffer buffers a continuous portion of the current output video data stream of the main layer generated by the video data encoder, the encoded picture buffer having an encoded picture buffer size; The video data encoder responds to parameter data associated with the output video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output video data stream, each level defining at least the maximum luminance picture size, the minimum compression ratio, and the maximum value of the coding picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the minimum compression ratio causes the coding image buffer size to define the coding image buffer to be sufficient to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression ratio factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

22. The apparatus according to claim 21, wherein, The continuous portion is the part that represents the data of the entire image.

23. A video storage, capture, transmission, or reception apparatus, comprising the apparatus according to claim 21.

24. A method for encoding video according to a generic video coding scheme, the method comprising: In response to parameter data associated with the output encoded video data stream, the input video data stream is encoded to generate the output encoded video data stream, the parameter data indicating a coding level selected from a plurality of coding levels for a given output encoded video data stream, each level defining at least the maximum value of the maximum luma picture size, minimum compression ratio, and encoded picture buffer size; and The output encoded video data stream of the main layer is buffered in an encoded picture buffer, the encoded picture buffer being configured to buffer consecutive portions of the output encoded video data stream generated through the encoding step, the encoded picture buffer having an encoded picture buffer size; Wherein, for each coding level of the main layer among the plurality of coding levels, the minimum compression ratio causes the coding image buffer size to define the coding image buffer sufficiently to buffer the number of bits required to represent the image at the maximum luminance image size when encoding according to the minimum compression ratio, wherein the minimum compression ratio depends on the minimum compression ratio cardinality and the minimum compression scaling factor, and When the value of the encoding level is 6, the minimum compression ratio base of the main layer is 8 and the maximum value of the encoded image buffer size is 80,000.

25. A machine-readable non-transient storage medium storing computer software, which, when executed by a computer, causes the computer to perform the method according to claim 24.

Images