Signaling quantization parameters in video processing

Abstract

To provide methods for processing video content.SOLUTION: One exemplary method comprises: receiving a bitstream comprising coded video data; determining a first parameter of a coding block; determining, according to the first parameter, one or more second parameters associated with a delta quantization parameter (QP) value or a chroma QP offset value; and determining, according to the one or more second parameters, at least one of the delta QP value and the chroma QP offset value.SELECTED DRAWING: Figure 21

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 903,251, filed September 20, 2019, which is incorporated by reference in its entirety.

[0002] Technical Field FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to video processing, and more particularly to methods and systems for processing video content with quantization parameters. [Background technology]

[0003] background

[0003] A video is a set of static pictures (or "frames") that capture visual information. To reduce storage memory and transmission bandwidth, video can be compressed before storage or transmission and decompressed before display. The compression process is usually called encoding, and the decompression process is usually called decoding. There are various video coding formats that use standardized video coding techniques, most commonly based on prediction, transform, quantization, entropy coding, and in-loop filtering. Video coding standards, such as the High Efficiency Video Coding (HEVC / H.265) standard, the Versatile Video Coding (VVC / H.266) standard, and the AVS standard, which specify specific video coding formats, are developed by standardization organizations. As more advanced video coding techniques are adopted into video standards, the coding efficiency of new video coding standards becomes higher. Summary of the Invention [Means for solving the problem]

[0004] Summary of the Disclosure

[0004] An embodiment of the present disclosure provides a computer-implemented method for processing video content, including receiving a bitstream including coded video data, determining a first parameter for the coded block, determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter, and determining at least one of the delta QP value or the chroma QP offset value according to the one or more second parameters.

[0005]

[0005] An embodiment of the present disclosure also provides a system for processing video content, comprising a memory storing a set of instructions and at least one processor, wherein the at least one processor is configured to execute the set of instructions to cause the system to receive a bitstream comprising coded video data, determine a first parameter for the coded block, determine one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value in accordance with the first parameter, and determine at least one of the delta QP value or the chroma QP offset value in accordance with the one or more second parameters.

[0006]

[0006] An embodiment of the present disclosure also provides a non-transitory computer-readable medium storing instructions executable by at least one processor of a computer system, wherein executing the instructions causes the computer system to perform a method including receiving a bitstream including coded video data, determining a first parameter for the coded block, determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter, and determining at least one of the delta QP value or the chroma QP offset value according to the one or more second parameters.

[0007] BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Embodiments and various aspects of the present disclosure are illustrated in the following detailed description and the accompanying drawings, in which various features are not drawn to scale. [Brief explanation of the drawings]

[0008] [Figure 1] 8 illustrates the structure of an exemplary video sequence consistent with embodiments of the present disclosure. [Figure 2A]

[0009] 1 shows a schematic diagram of an exemplary encoding process for a hybrid video coding system consistent with embodiments of the present disclosure. [Figure 2B]

[0010] 1 shows a schematic diagram of another exemplary encoding process for a hybrid video coding system consistent with embodiments of the present disclosure. [Figure 3A]

[0011] 1 shows a schematic diagram of an exemplary decoding process for a hybrid video coding system consistent with embodiments of the present disclosure. [Figure 3B]

[0012] 1 shows a schematic diagram of another exemplary decoding process for a hybrid video coding system consistent with embodiments of the present disclosure. [Figure 4]

[0013] 1 is a block diagram of an exemplary device for encoding or decoding video consistent with embodiments of the present disclosure. [Figure 5]

[0014] 1 illustrates an example picture parameter set (PPS) for coded unit (CU) delta quantization parameters (QP), consistent with embodiments of this disclosure. [Figure 6A]

[0015] 1 illustrates an example of a coding tree-level syntax for CU delta QP, consistent with embodiments of the present disclosure. [Figure 6B] 1 illustrates an example of a coding tree-level syntax for CU delta QP consistent with embodiments of the present disclosure. [Figure 6C] 1 illustrates an example of a coding tree-level syntax for CU delta QP consistent with embodiments of the present disclosure. [Figure 7A]

[0016] 10 illustrates an example of a transform unit level syntax for CU delta QP, consistent with embodiments of the present disclosure. [Figure 7B] 1 illustrates an example of a transform unit level syntax for CU delta QP consistent with embodiments of this disclosure. [Figure 7C] 1 illustrates an example of a transform unit level syntax for CU delta QP consistent with embodiments of this disclosure. [Figure 8]

[0017] 1 illustrates an example of slice header syntax consistent with embodiments of the present disclosure. [Figure 9]

[0018] 10 illustrates another example of slice header syntax consistent with embodiments of the present disclosure. [Figure 10]

[0019] 10 illustrates yet another example of slice header syntax consistent with embodiments of the present disclosure. [Figure 11]

[0020] 10 illustrates another example of a picture header syntax consistent with embodiments of the present disclosure. [Figure 12]

[0021] 10 illustrates an example of PPS syntax for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv, consistent with embodiments of the present disclosure. [Figure 13]

[0022] 10 illustrates an example of slice header syntax for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv, consistent with embodiments of the present disclosure. [Figure 14]

[0023] 10 illustrates an example of syntax for sps_max_mtt_depth_luma consistent with embodiments of the present disclosure. [Figure 15]

[0024] 10 illustrates an example of syntax for pps_max_mtt_depth_luma consistent with embodiments of the present disclosure. [Figure 16]

[0025] 10 shows an example of SPS syntax for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv, consistent with embodiments of the present disclosure. [Figure 17]

[0026] 10 illustrates an example of slice header syntax for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv, consistent with embodiments of the present disclosure. [Figure 18]

[0027] 10 illustrates an example of syntax for sps_max_mtt_depth_luma consistent with embodiments of the present disclosure. [Figure 19]

[0028] 10 illustrates another example of syntax for sps_max_mtt_depth_luma, consistent with embodiments of the present disclosure. [Figure 20]

[0029] 10 illustrates an example of syntax for pps_max_mtt_depth_luma consistent with embodiments of the present disclosure. [Figure 21]

[0030] 1 is a flow diagram of an exemplary computer-implemented method for processing video content consistent with embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009]

[0031] Video coding systems are often used to compress digital video signals, for example to reduce the storage space consumed or to reduce the transmission bandwidth consumption associated with such signals. With the increasing popularity of high-definition (HD) video (e.g., having a resolution of 1920x1080 pixels) in various applications of video compression, such as online video streaming, video conferencing, or video surveillance, there is a continuing need to develop video coding tools that can increase the efficiency of compressing video data.

[0010]

[0032] For example, video surveillance applications are becoming more and more widely used in many application scenarios (e.g., security, traffic, environmental monitoring, etc.), and the number and resolution of surveillance devices are increasing rapidly. Many video surveillance application scenarios choose to provide users with HD video to capture more information, and HD video has more pixels per frame to capture such information. However, HD video bitstreams may have high bitrates that require high bandwidth for transmission and large storage space. For example, a surveillance video stream with an average resolution of 1920 x 1080 may require as much as 4 Mbps of bandwidth for real-time transmission. Furthermore, video surveillance generally involves continuous monitoring, which can pose great challenges to storage systems when storing video data. Therefore, the high bandwidth and large storage space demands of HD video have become major limitations to the large-scale deployment of HD video in video surveillance.

[0011]

[0033] A video is a set of still pictures (or "frames") arranged in chronological order to store visual information. A video capture device (e.g., a camera) can be used to capture and store these pictures in chronological order, and a video playback device (e.g., a television, a computer, a smartphone, a tablet computer, a video player, or any end-user terminal with display capabilities) can be used to display these pictures in chronological order. Furthermore, in some applications, a video capture device can transmit captured video in real time to a video playback device (e.g., a computer with a monitor) for purposes such as surveillance, conferencing, or live broadcasting.

[0012]

[0034] To reduce the storage space and transmission bandwidth required by such applications, video can be compressed before storage and transmission and decompressed before display. This compression and decompression can be implemented by software executed by a processor (e.g., a processor in a general-purpose computer) or dedicated hardware. A module for compression is generally referred to as an "encoder," and a module for decompression is generally referred to as a "decoder." Encoders and decoders can be collectively referred to as a "codec." Encoders and decoders can be implemented as various suitable hardware, software, or combinations thereof. For example, hardware implementations of encoders and decoders may include circuitry such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, or any combination thereof. Software implementations of encoders and decoders may include program code, computer-executable instructions, firmware, or any suitable computer-implemented algorithm or process fixed in a computer-readable medium. Video compression and decompression may be implemented by various algorithms or standards, such as MPEG-1, MPEG-2, MPEG-4, H.26x series, etc. In some applications, a codec may decompress video from a first coding standard and recompress the decompressed video using a second coding standard, in which case the codec may be called a "transcoder."

[0013]

[0035] A video coding process can identify and retain useful information that can be used to reconstruct a picture and ignore information that is not important for reconstruction. If the ignored, unimportant information cannot be perfectly reconstructed, then such a coding process can be called "lossy." Otherwise, such a coding process can be called "lossless." Most coding processes are lossy; this is a tradeoff to reduce the required storage space and transmission bandwidth.

[0014]

[0036] Useful information about the picture being coded (called the "current picture") includes changes relative to a reference picture (e.g., a previously coded and reconstructed picture). Such changes can include pixel position changes, luminance changes, or color changes, of which position changes are the most important. Position changes of pixels representing an object can reflect the movement of the object between the reference picture and the current picture.

[0015]

[0037] A picture that is coded without reference to another picture (i.e., such a picture is its own reference picture) is called an "I-picture." A picture that is coded using a past picture as a reference picture is called a "P-picture." A picture that is coded using both past and future pictures as reference pictures (i.e., the referencing is "bidirectional") is called a "B-picture."

[0016]

[0038] As mentioned above, video surveillance using HD video faces the challenges of high bandwidth and large storage demands. To address this challenge, the bit rate of the encoded video can be reduced. Among I-, P-, and B-pictures, I-pictures have the highest bit rate. Because the background of most surveillance video is nearly static, one way to reduce the overall bit rate of the encoded video can be to use fewer I-pictures for video encoding.

[0017]

[0039] However, because I-pictures are generally undominant in coded video, the improvement of using fewer I-pictures may be trivial. For example, in a typical video bitstream, the ratio of I-pictures, B-pictures, and P-pictures may be 1:20:9, with I-pictures accounting for less than 10% of the total bitrate. In other words, in such an example, removing all I-pictures may only result in a 10% reduction in bitrate.

[0018]

[0040] The present disclosure provides a method, apparatus, and system for processing video content using adaptive resolution change (ARC). Unlike the inaccurate phase caused by phase rounding, embodiments of the present disclosure provide a pixel refinement process based on fixed-phase interpolation to reduce algorithm and hardware complexity while maintaining accuracy.

[0019]

[0041] 1 illustrates the structure of an example video sequence 100 consistent with embodiments of the present disclosure. The video sequence 100 may be live video or captured and archived video. The video 100 may be real video, computer-generated video (e.g., computer game video), or a combination thereof (e.g., real video with augmented reality effects). The video sequence 100 may be input from a video capture device (e.g., a camera), a video archive containing previously captured video (e.g., video files stored in a storage device), or a video feed interface (e.g., a video broadcast transceiver) for receiving video from a video content provider.

[0020]

[0042] As shown in FIG. 1, video sequence 100 may include a series of pictures arranged temporally along a timeline, including pictures 102, 104, 106, and 108. Pictures 102-106 are consecutive, with more pictures between pictures 106 and 108. In FIG. 1, picture 102 is an I-picture, and its reference picture is picture 102 itself. Picture 104 is a P-picture, and its reference picture is picture 102, as indicated by the arrow. Picture 106 is a B-picture, and its reference pictures are pictures 104 and 108, as indicated by the arrows. In some embodiments, the reference picture of a picture (e.g., picture 104) need not immediately precede or follow that picture. For example, the reference picture of picture 104 may be a picture preceding picture 102. It should be noted that the reference pictures of pictures 102-106 are merely examples, and this disclosure does not limit the reference picture embodiments to the examples shown in FIG.

[0021]

[0043] Typically, video codecs do not encode or decode an entire picture at once because such a task is computationally complex. Rather, video codecs may divide a picture into elementary segments and encode or decode the picture segment by segment. In this disclosure, such elementary segments are referred to as basic processing units ("BPUs"). For example, structure 110 in FIG. 1 illustrates an example structure for a picture (e.g., any of pictures 102-108) in video sequence 100. In structure 110, the picture is divided into 4x4 basic processing units, the boundaries of which are indicated by dashed lines. In some embodiments, the basic processing units may be referred to as "macroblocks" in some video coding standards (e.g., MPEG family, H.261, H.263, or H.264 / AVC) and as "coding tree units" ("CTUs") in some other video coding standards (e.g., H.265 / HEVC or H.266 / VVC). Basic processing units can have variable sizes within a picture, such as 128x128, 64x64, 32x32, 16x16, 4x8, 16x32, or any arbitrary shape and size of pixels. The size and shape of the basic processing unit can be selected for a picture based on a balance between coding efficiency and the level of detail one wishes to preserve within the basic processing unit.

[0022]

[0044] A basic processing unit may be a logical unit that may include various types of video data stored in computer memory (e.g., in a video frame buffer). For example, a basic processing unit for a color picture may include a luma component (Y) representing achromatic luminance information, one or more chroma components (e.g., Cb and Cr) representing color information, and associated syntax elements of the basic processing unit, where the luma and chroma components may have the same size. In some video coding standards (e.g., H.265 / HEVC or H.266 / VVC), the luma and chroma components may be referred to as "coding tree blocks" ("CTBs"). Any operation performed on a basic processing unit can be repeated for each of its luma and chroma components.

[0023]

[0045] Video coding involves multiple stages of operation, examples of which are detailed in Figures 2A-2B and 3A-3B. For each stage, the size of the basic processing unit may still be too large to process and therefore may be further divided into segments referred to in this disclosure as "basic processing sub-units." In some embodiments, the basic processing sub-units may be referred to as "blocks" in some video coding standards (e.g., MPEG family, H.261, H.263, or H.264 / AVC) or as "coding units" ("CUs") in some other video coding standards (e.g., H.265 / HEVC or H.266 / VVC). The basic processing sub-units may have the same or smaller size than the basic processing units. Similar to basic processing units, basic processing sub-units are also logical units that may contain various types of video data (e.g., Y, Cb, Cr, and related syntax elements) stored in computer memory (e.g., in a video frame buffer). Any operation performed on a basic processing sub-unit can be repeated for each of its luma and chroma components. It should be noted that such division can be performed to further levels depending on the processing needs. It should also be noted that different stages can divide the basic processing unit using different schemes.

[0024]

[0046] For example, in a mode decision stage (one example of which is detailed in FIG. 2B ), the encoder may decide which prediction mode (e.g., intra-picture prediction or inter-picture prediction) to use for a basic processing unit, which may be too large to make such a decision. The encoder may divide the basic processing unit into multiple basic processing sub-units (e.g., CUs in H.265 / HEVC or H.266 / VVC) and determine the type of prediction for each individual basic processing sub-unit.

[0025]

[0047] In another example, in the prediction stage (one example of which is detailed in FIG. 2A), the encoder can perform prediction operations at the level of elementary processing sub-units (e.g., CUs). However, in some cases, elementary processing sub-units may still be too large to process. The encoder can further divide the elementary processing sub-units into smaller segments (e.g., called "prediction blocks" or "PBs" in H.265 / HEVC or H.266 / VVC) and perform prediction operations at that level.

[0026]

[0048] In another example, in the transform stage (one example of which is detailed in FIG. 2A ), the encoder can perform a transform operation on a residual elementary processing sub-unit (e.g., a CU). However, in some cases, the elementary processing sub-unit may still be too large to process. The encoder can further divide the elementary processing sub-unit into smaller segments (e.g., called "transform blocks" or "TBs" in H.265 / HEVC or H.266 / VVC) and perform the transform operation at that level. It should be noted that the division scheme of the same elementary processing sub-unit may be different between the prediction stage and the transform stage. For example, in H.265 / HEVC or H.266 / VVC, the prediction blocks and transform blocks of the same CU may have different sizes and numbers.

[0027]

[0049] In structure 110 of Figure 1, basic processing units 112 are further divided into 3x3 basic processing sub-units, the boundaries of which are shown by dotted lines. Different basic processing units of the same picture can be divided into basic processing sub-units in different ways.

[0028]

[0050] In some implementations, to provide parallel processing and error resilience for video encoding and decoding, a picture can be divided into regions for processing, thereby allowing the encoding or decoding process for a region of a picture to not depend on information from any other region of the picture. In other words, each region of a picture can be processed independently. This allows a codec to process different regions of a picture in parallel, thus increasing coding efficiency. Furthermore, if data for a region is corrupted during processing or lost during network transmission, the codec can correctly encode or decode other regions of the same picture without relying on the corrupted or lost data, thus providing error resilience. Some video coding standards allow a picture to be divided into different types of regions. For example, H.265 / HEVC and H.266 / VVC provide two types of regions: "slices" and "tiles." It should also be noted that various pictures in video sequence 100 may have different partitioning schemes for dividing the picture into regions.

[0029]

[0051] For example, in Figure 1, structure 110 is divided into three regions 114, 116, and 118, the boundaries of which are shown as solid lines within structure 110. Region 114 includes four basic processing units. Regions 116 and 118 each include six basic processing units. It should be noted that the basic processing units, basic processing sub-units, and regions of structure 110 in Figure 1 are merely examples, and the present disclosure does not limit the embodiments thereof.

[0030]

[0052] FIG. 2A shows a schematic diagram of an example encoding process 200A consistent with embodiments of this disclosure. An encoder may encode a video sequence 202 into a video bitstream 228 according to process 200A. Similar to video sequence 100 of FIG. 1, video sequence 202 may include a set of pictures (referred to as "original pictures") arranged in chronological order. Similar to structure 110 of FIG. 1, each original picture of video sequence 202 may be divided by the encoder into basic processing units, basic processing sub-units, or regions for processing. In some embodiments, the encoder may perform process 200A at the level of the basic processing units for each original picture of video sequence 202. For example, the encoder may perform process 200A in an iterative manner, where the encoder may encode a basic processing unit in one iteration of process 200A. In some embodiments, the encoder may perform process 200A in parallel for regions (e.g., regions 114-118) of each original picture of video sequence 202.

[0031]

[0053] In FIG. 2A , an encoder may feed a basic processing unit (referred to as an “original BPU”) of an original picture of a video sequence 202 to a prediction stage 204 to generate prediction data 206 and a predicted BPU 208. The encoder may subtract the predicted BPU 208 from the original BPU to generate a residual BPU 210. The encoder may feed the residual BPU 210 to a transform stage 212 and a quantization stage 214 to generate quantized transform coefficients 216. The encoder may feed the prediction data 206 and the quantized transform coefficients 216 to a binary coding stage 226 to generate a video bitstream 228. Components 202, 204, 206, 208, 210, 212, 214, 216, 226, and 228 may be referred to as a “forward path.” During process 200A, after quantization stage 214, the encoder may feed quantized transform coefficients 216 to inverse quantization stage 218 and inverse transform stage 220 to generate a reconstructed residual BPU 222. The encoder may add the reconstructed residual BPU 222 to predicted BPU 208 to generate a prediction reference 224 used in prediction stage 204 of the next iteration of process 200A. Components 218, 220, 222, and 224 of process 200A may be referred to as a "reconstruction path." The reconstruction path may be used to ensure that both the encoder and decoder use the same reference data for prediction.

[0032]

[0054] The encoder may iteratively perform process 200A to encode each original BPU of the original picture (in the forward path) and generate a predicted reference 224 for encoding the next original BPU of the original picture (in the reconstruction path). After encoding all original BPUs of the original picture, the encoder may proceed to encode the next picture in the video sequence 202.

[0033]

[0055] Referring to process 200A, an encoder may receive a video sequence 202 generated by a video capture device (e.g., a camera). As used herein, the term "receive" may refer to any action of receiving, inputting, obtaining, retrieving, acquiring, reading, accessing, or any manner of inputting data.

[0034]

[0056] In the prediction stage 204, in the current iteration, the encoder receives the original BPU and a prediction reference 224 and can perform a prediction operation to generate prediction data 206 and a predicted BPU 208. The prediction reference 224 can be generated from the reconstruction path of a previous iteration of the process 200A. The purpose of the prediction stage 204 is to reduce information redundancy by extracting prediction data 206, which can be used to reconstruct the original BPU from the prediction data 206 and the prediction reference 224 as a predicted BPU 208.

[0035]

[0057] Ideally, predicted BPU 208 would be identical to the original BPU. However, due to non-ideal prediction and reconstruction operations, predicted BPU 208 generally differs slightly from the original BPU. To record such differences, after generating predicted BPU 208, the encoder may subtract it from the original BPU to generate residual BPU 210. For example, the encoder may subtract pixel values ​​(e.g., grayscale or RGB values) of predicted BPU 208 from corresponding pixel values ​​of the original BPU. As a result of such subtraction between corresponding pixels of the original BPU and predicted BPU 208, each pixel of residual BPU 210 may have a residual value. Compared to the original BPU, prediction data 206 and residual BPU 210 may have fewer bits, which can be used to reconstruct the original BPU without significant loss of quality.

[0036]

[0058] To further compress the residual BPU 210, in the transform stage 212, the encoder can reduce spatial redundancy in the residual BPU 210 by decomposing the residual BPU 210 into a set of two-dimensional "basis patterns," each associated with a "transform coefficient." The basis patterns can have the same size (e.g., the size of the residual BPU 210). Each basis pattern can represent a variation frequency (e.g., luminance variation frequency) component of the residual BPU 210. None of the basis patterns can be reconstructed from any combination (e.g., a linear combination) of any other basis patterns. In other words, the decomposition can decompose the variation of the residual BPU 210 into the frequency domain. Such a decomposition is similar to a discrete Fourier transform of a function, the basis patterns are similar to basis functions (e.g., trigonometric functions) of the discrete Fourier transform, and the transform coefficients are similar to the coefficients associated with the basis functions.

[0037]

[0059] Different transform algorithms can use different basis patterns. For example, various transform algorithms can be used in transform stage 212, such as a discrete cosine transform, a discrete sine transform, etc. The transform in transform stage 212 is reversible. That is, the encoder can reconstruct residual BPU 210 by inversely operating the transform (referred to as an "inverse transform"). For example, to reconstruct a pixel of residual BPU 210, the inverse transform can multiply the value of the corresponding pixel in the basis pattern by the associated respective coefficient and add the products to obtain a weighted sum. In video coding standards, both the encoder and decoder can use the same transform algorithm (and therefore the same basis pattern). Therefore, the encoder can record only the transform coefficients, and the decoder can reconstruct residual BPU 210 from the transform coefficients without receiving the basis pattern from the encoder. Although the transform coefficients may have fewer bits compared to residual BPU 210, they can be used to reconstruct residual BPU 210 without significant loss of quality. Therefore, the residual BPU 210 is further compressed.

[0038]

[0060] The encoder can further compress the transform coefficients in the quantization stage 214. In the transform process, different basis patterns can represent different fluctuation frequencies (e.g., luminance fluctuation frequencies). Because the human eye is generally good at recognizing low-frequency fluctuations, the encoder can ignore high-frequency fluctuation information without causing significant quality degradation during decoding. For example, in the quantization stage 214, the encoder can generate quantized transform coefficients 216 by dividing each transform coefficient by an integer value (referred to as a "quantization parameter") and rounding the quotient to its nearest neighbor. After such an operation, some transform coefficients of high-frequency basis patterns can be converted to zero, and transform coefficients of low-frequency basis patterns can be converted to smaller integers. The encoder can ignore zero-valued quantized transform coefficients 216, thereby further compressing the transform coefficients. The quantization process is also reversible, and the quantized transform coefficients 216 can be reconstructed into transform coefficients in the inverse operation of quantization (referred to as "dequantization").

[0039]

[0061] Quantization stage 214 may be lossy because the encoder ignores the remainder of such a division in a rounding operation. Typically, quantization stage 214 may contribute the greatest information loss in process 200A. The greater the information loss, the fewer bits the quantized transform coefficients 216 may require. To achieve different levels of information loss, the encoder may use different values ​​of the quantization parameter or any other parameter of the quantization process.

[0040]

[0062] In the binary coding stage 226, the encoder may encode the prediction data 206 and the quantized transform coefficients 216 using a binary coding technique, such as entropy coding, variable length coding, arithmetic coding, Huffman coding, context-adaptive binary arithmetic coding, or any other lossless or lossy compression algorithm. In some embodiments, in addition to the prediction data 206 and the quantized transform coefficients 216, the encoder may encode other information in the binary coding stage 226, such as the prediction mode used in the prediction stage 204, parameters of the prediction operation, the type of transform in the transform stage 212, parameters of the quantization process (e.g., quantization parameters), and encoder control parameters (e.g., bitrate control parameters). The encoder may generate a video bitstream 228 using the output data of the binary coding stage 226. In some embodiments, the video bitstream 228 may be further packetized for network transmission.

[0041]

[0063] Referring to the reconstruction path of process 200A, in an inverse quantization stage 218, the encoder may perform inverse quantization on the quantized transform coefficients 216 to generate reconstructed transform coefficients. In an inverse transform stage 220, the encoder may generate a reconstructed residual BPU 222 based on the reconstructed transform coefficients. The encoder may add the reconstructed residual BPU 222 to the predicted BPU 208 to generate a prediction reference 224 to be used in the next iteration of process 200A.

[0042]

[0064] It should be noted that other variations of process 200A can be used to encode video sequence 202. In some embodiments, an encoder can perform the stages of process 200A in a different order. In some embodiments, one or more stages of process 200A can be combined into a single stage. In some embodiments, a single stage of process 200A can be separated into multiple stages. For example, transform stage 212 and quantization stage 214 can be combined into a single stage. In some embodiments, process 200A can include additional stages. In some embodiments, process 200A can omit one or more stages in FIG. 2A .

[0043]

[0065] 2B shows a schematic diagram of another example encoding process 200B consistent with embodiments of the present disclosure. Process 200B may be modified from process 200A. For example, process 200B may be used by an encoder compliant with a hybrid video coding standard (e.g., the H.26x series). Compared to process 200A, the forward path of process 200B further includes a mode decision stage 230 and separates prediction stage 204 into a spatial prediction stage 2042 and a temporal prediction stage 2044. The reconstruction path of process 200B additionally includes a loop filter stage 232 and a buffer 234.

[0044]

[0066] Generally, prediction techniques can be categorized into two types: spatial prediction and temporal prediction. Spatial prediction (e.g., intra-picture prediction or "intra-prediction") can use pixels of one or more already coded neighboring BPUs in the same picture to predict the current BPU. That is, the prediction reference 224 in spatial prediction can include neighboring BPUs. Spatial prediction can reduce the inherent spatial redundancy of a picture. Temporal prediction (e.g., inter-picture prediction or "inter-prediction") can use regions of one or more already coded pictures to predict the current BPU. That is, the prediction reference 224 in temporal prediction can include coded pictures. Temporal prediction can reduce the inherent temporal redundancy of a picture.

[0045]

[0067] Referring to process 200B, in the forward path, the encoder performs prediction operations in a spatial prediction stage 2042 and a temporal prediction stage 2044. For example, in the spatial prediction stage 2042, the encoder may perform intra prediction. With respect to an original BPU of a picture being coded, the prediction reference 224 may include one or more neighboring BPUs coded (in the forward path) and reconstructed (in the reconstruction path) within the same picture. The encoder may generate the predicted BPU 208 by extrapolating the neighboring BPUs. Extrapolation techniques may include, for example, linear extrapolation or interpolation, polynomial extrapolation or interpolation, etc. In some embodiments, the encoder may perform extrapolation at the pixel level, such as by extrapolating the value of the corresponding pixel for each pixel of the predicted BPU 208. The neighboring BPUs used for extrapolation may be located relative to the original BPU from various directions, such as vertically (e.g., above the original BPU), horizontally (e.g., to the left of the original BPU), diagonally (e.g., bottom-left, bottom-right, top-left, or top-right of the original BPU), or any direction specified within the video coding standard used. For intra prediction, the prediction data 206 may include, for example, the positions (e.g., coordinates) of the neighboring BPUs used, the sizes of the neighboring BPUs used, parameters of the extrapolation, the orientation of the neighboring BPUs used relative to the original BPU, etc.

[0046]

[0068] In another example, in the temporal prediction stage 2044, the encoder may perform inter-prediction. With respect to the original BPU of the current picture, the prediction reference 224 may include one or more pictures (referred to as "reference pictures") that have been coded (in the forward path) and reconstructed (in the reconstruction path). In some embodiments, a reference picture may be coded and reconstructed for each BPU. For example, the encoder may add the reconstructed residual BPU 222 to the predicted BPU 208 to generate a reconstructed BPU. Once all reconstructed BPUs of the same picture are generated, the encoder may generate the reconstructed picture as a reference picture. The encoder may perform a "motion estimation" operation to search for a matching region within a range (referred to as a "search window") of the reference picture. The position of the search window in the reference picture may be determined based on the position of the original BPU in the current picture. For example, the search window may be centered in the reference picture at a location having the same coordinates as the original BPU in the current picture and may extend over a predetermined distance. When the encoder identifies a region within the search window that is similar to the original BPU (e.g., by using a pel recursion algorithm, a block matching algorithm, etc.), the encoder can determine that region as a matching region. The matching region may have different dimensions (e.g., smaller, equal, larger, or different shape) than the original BPU. Because the reference picture and the current picture are separated in time in a timeline (e.g., as shown in FIG. 1), the matching region can be considered to "move" to the position of the original BPU over time. The encoder can record the direction and distance of such movement as a "motion vector." If multiple reference pictures are used (e.g., picture 106 in FIG. 1), the encoder can find the matching region for each reference picture and determine its associated motion vector. In some embodiments, the encoder can assign weights to the pixel values ​​of the matching region in each matching reference picture.

[0047]

[0069] Motion estimation can be used to identify various types of motion, such as, for example, translation, rotation, scaling, etc. In inter prediction, prediction data 206 may include, for example, the location (e.g., coordinates) of the matching region, a motion vector associated with the matching region, the number of reference pictures, weights associated with the reference pictures, etc.

[0048]

[0070] To generate the predicted BPU 208, the encoder may perform a "motion compensation" operation. Motion compensation may be used to reconstruct the predicted BPU 208 based on the prediction data 206 (e.g., a motion vector) and the prediction reference 224. For example, the encoder may shift matching regions of a reference picture according to a motion vector, within which the encoder may predict the original BPU of the current picture. If multiple reference pictures are used (e.g., picture 106 of FIG. 1), the encoder may shift matching regions of the reference pictures according to their respective motion vectors and average pixel values ​​of the matching regions. In some embodiments, if the encoder assigns weights to pixel values ​​of the matching regions of the respective matching reference pictures, the encoder may add a weighted sum of pixel values ​​of the shifted matching regions.

[0049]

[0071] In some embodiments, inter-prediction can be unidirectional or bidirectional. Unidirectional inter-prediction can use one or more reference pictures that are in the same temporal direction relative to the current picture. For example, picture 104 in FIG. 1 is a unidirectional inter-predicted picture in which the reference picture (i.e., picture 102) precedes picture 104. Bidirectional inter-prediction can use one or more reference pictures that are in both temporal directions relative to the current picture. For example, picture 106 in FIG. 1 is a bidirectional inter-predicted picture in which the reference pictures (i.e., pictures 104 and 108) are in both temporal directions relative to picture 104.

[0050]

[0072] Continuing with reference to the forward path of process 200B, after spatial prediction step 2042 and temporal prediction step 2044, in mode decision step 230, the encoder may select a prediction mode (e.g., one of intra-prediction or inter-prediction) for the current iteration of process 200B. For example, the encoder may perform a rate-distortion optimization technique, in which the encoder may select a prediction mode to minimize the value of a cost function depending on the bitrates of the candidate prediction modes and the distortion of the reconstructed reference picture under the candidate prediction modes. Depending on the selected prediction mode, the encoder may generate a corresponding predicted BPU 208 and predicted data 206.

[0051]

[0073] In the reconstruction path of process 200B, if an intra-prediction mode is selected in the forward path, after generating a prediction reference 224 (e.g., a current BPU that has been coded and reconstructed in a current picture), the encoder can directly feed the prediction reference 224 to a spatial prediction stage 2042 for later use (e.g., to extrapolate the next BPU of the current picture). If an inter-prediction mode is selected in the forward path, after generating a prediction reference 224 (e.g., a current picture in which all BPUs have been coded and reconstructed), the encoder can feed the prediction reference 224 to a loop filter stage 232, where the encoder can apply a loop filter to the prediction reference 224 to reduce or eliminate distortions (e.g., blocking artifacts) caused by inter-prediction. For example, the encoder can apply various loop filter techniques in the loop filter stage 232, such as deblocking, sample adaptive offset, adaptive loop filter, etc. The loop filtered reference pictures may be stored in a buffer 234 (or "decoded picture buffer") for later use (e.g., for use as inter-prediction reference pictures for future pictures in the video sequence 202). The encoder may store one or more reference pictures in the buffer 234 for use in the temporal prediction stage 2044. In some embodiments, the encoder may encode loop filter parameters (e.g., loop filter strength) in a binary coding stage 226 along with the quantized transform coefficients 216, the prediction data 206, and other information.

[0052]

[0074] FIG. 3A shows a schematic diagram of an example decoding process 300A consistent with embodiments of the present disclosure. Process 300A may be a decompression process corresponding to compression process 200A of FIG. 2A. In some embodiments, process 300A may be similar to the reconstruction path of process 200A. A decoder may follow process 300A to decode video bitstream 228 into video stream 304. Video stream 304 may be very similar to video sequence 202. However, due to information loss in the compression and decompression processes (e.g., quantization stage 214 of FIGS. 2A-2B), video stream 304 is generally not identical to video sequence 202. Similar to processes 200A and 200B of FIGS. 2A-2B, a decoder may perform process 300A at the level of a basic processing unit (BPU) for each picture encoded in video bitstream 228. For example, the decoder may perform process 300A in an iterative manner, where the decoder may decode a basic processing unit in one iteration of process 300A. In some embodiments, the decoder may perform process 300A in parallel for a region (e.g., regions 114-118) of each picture encoded in video bitstream 228.

[0053]

[0075] In FIG. 3A , a decoder may feed a portion of a video bitstream 228 associated with a basic processing unit of a coded picture (referred to as a “coded BPU”) to a binary decoding stage 302. In the binary decoding stage 302, the decoder may decode the portion into prediction data 206 and quantized transform coefficients 216. The decoder may feed the quantized transform coefficients 216 to an inverse quantization stage 218 and an inverse transform stage 220 to generate a reconstructed residual BPU 222. The decoder may feed the prediction data 206 to a prediction stage 204 to generate a predicted BPU 208. The decoder may add the reconstructed residual BPU 222 to the predicted BPU 208 to generate a predicted reference 224. In some embodiments, the predicted reference 224 may be stored in a buffer (e.g., a decoded picture buffer in computer memory). The decoder may feed the predicted reference 224 to the prediction stage 204 for performing a prediction operation in a next iteration of the process 300A.

[0054]

[0076] The decoder may iteratively perform process 300A to decode each coded BPU of the coded picture and generate a predicted reference 224 for coding the next coded BPU of the coded picture. After decoding all coded BPUs of the coded picture, the decoder may output the picture to the video stream 304 for display and proceed to decode the next coded picture in the video bitstream 228.

[0055]

[0077] In binary decoding stage 302, the decoder may perform the inverse operation of the binary coding technique used by the encoder (e.g., entropy coding, variable length coding, arithmetic coding, Huffman coding, context-adaptive binary arithmetic coding, or any other lossless compression algorithm). In some embodiments, in addition to prediction data 206 and quantized transform coefficients 216, the decoder may decode other information in binary decoding stage 302, such as, for example, a prediction mode, parameters of the prediction operation, type of transform, parameters of the quantization process (e.g., quantization parameters), encoder control parameters (e.g., bitrate control parameters), etc. In some embodiments, if video bitstream 228 is transmitted in packets over a network, the decoder may depacketize video bitstream 228 before feeding it to binary decoding stage 302.

[0056]

[0078] 3B shows a schematic diagram of another example decoding process 300B consistent with embodiments of the present disclosure. Process 300B may be modified from process 300A. For example, process 300B may be used by a decoder that complies with a hybrid video coding standard (e.g., the H.26x series). Compared to process 300A, process 300B further divides prediction stage 204 into spatial prediction stage 2042 and temporal prediction stage 2044, and additionally includes loop filter stage 232 and buffer 234.

[0057]

[0079] In process 300B, for a coded basic processing unit (referred to as a "current BPU") of a coded picture being decoded (referred to as a "current picture"), prediction data 206 decoded by the decoder from binary decoding stage 302 may include various types of data depending on which prediction mode was used by the encoder to code the current BPU. For example, if intra prediction was used by the encoder to code the current BPU, prediction data 206 may include a prediction mode indicator (e.g., a flag value) indicating intra prediction, parameters of the intra prediction operation, etc. The parameters of the intra prediction operation may include, for example, the positions (e.g., coordinates) of one or more neighboring BPUs used as references, sizes of the neighboring BPUs, parameters of extrapolation, directions of the neighboring BPUs relative to the original BPU, etc. In another example, if inter prediction was used by the encoder to code the current BPU, prediction data 206 may include a prediction mode indicator (e.g., a flag value) indicating inter prediction, parameters of the inter prediction operation, etc. Parameters for inter-prediction operations may include, for example, the number of reference pictures associated with the current BPU, weights associated with each of the reference pictures, the locations (e.g., coordinates) of one or more matching regions within each reference picture, one or more motion vectors associated with each of the matching regions, etc.

[0058]

[0080] Based on the prediction mode indicator, the decoder may decide whether to perform spatial prediction (e.g., intra prediction) in a spatial prediction step 2042 or temporal prediction (e.g., inter prediction) in a temporal prediction step 2044. Details of performing such spatial or temporal prediction are shown in FIG. 2B and will not be repeated below. After performing such spatial or temporal prediction, the decoder may generate a predicted BPU 208. As described in FIG. 3A, the decoder may add the predicted BPU 208 and the reconstructed residual BPU 222 to generate a prediction reference 224.

[0059]

[0081] In process 300B, the decoder may feed the predicted reference 224 to a spatial prediction stage 2042 or a temporal prediction stage 2044 for performing a prediction operation within the next iteration of process 300B. For example, if the current BPU is decoded using intra prediction in spatial prediction stage 2042, after generating the prediction reference 224 (e.g., the decoded current BPU), the decoder may feed the prediction reference 224 directly to spatial prediction stage 2042 for later use (e.g., to extrapolate the next BPU of the current picture). If the current BPU is decoded using inter prediction in temporal prediction stage 2044, after generating the prediction reference 224 (e.g., the reference picture from which all BPUs are decoded), the encoder may feed the prediction reference 224 to a loop filter stage 232 to reduce or eliminate distortion (e.g., blocking artifacts). The decoder may apply a loop filter to the prediction reference 224 in the manner described in FIG. 2B . The loop filtered reference pictures may be stored in a buffer 234 (e.g., a decoded picture buffer in computer memory) for later use (e.g., for use as inter-prediction reference pictures for future coded pictures of the video bitstream 228). The decoder may store one or more reference pictures in the buffer 234 for use in the temporal prediction stage 2044. In some embodiments, if the prediction mode indicator in the prediction data 206 indicates that inter-prediction was used to encode the current BPU, the prediction data may further include loop filter parameters (e.g., loop filter strength).

[0060]

[0082] FIG. 4 is a block diagram of an example device 400 for encoding or decoding video consistent with embodiments of the present disclosure. As shown in FIG. 4, device 400 may include a processor 402. When processor 402 executes the instructions described herein, device 400 may become a dedicated machine for encoding or decoding video. Processor 402 may be any type of circuit capable of manipulating or processing information. For example, processor 402 may include any combination of any number of central processing units (“CPUs”), graphics processing units (“GPUs”), neural processing units (“NPUs”), microcontroller units (“MCUs”), optical processors, programmable logic controllers, microcontrollers, microprocessors, digital signal processors, intellectual property (IP) cores, programmable logic arrays (PLAs), programmable array logic (PALs), general purpose array logic (GALs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), systems-on-chips (SoCs), application-specific integrated circuits (ASICs), etc. In some embodiments, processor 402 may be a set of processors grouped together as a single logical entity. For example, as shown in Figure 4, processor 402 may include multiple processors, including processor 402a, processor 402b, and processor 402n.

[0061]

[0083] Device 400 may also include memory 404 configured to store data (e.g., a set of instructions, computer code, intermediate data, etc.). For example, as shown in FIG. 4, the stored data may include program instructions (e.g., program instructions for implementing steps in processes 200A, 200B, 300A, or 300B) and data for processing (e.g., video sequence 202, video bitstream 228, or video stream 304). Processor 402 can access the program instructions and data for processing (e.g., via bus 410) and execute the program instructions to operate on or process the data for processing. Memory 404 may include high-speed random access storage or non-volatile storage. In some embodiments, memory 404 may include any combination of any number of random access memory (RAM), read-only memory (ROM), optical disks, magnetic disks, hard drives, solid-state drives, flash drives, security digital (SD) cards, memory sticks, compact flash (CF) cards, etc. Memory 404 may also be a collection of memories (not shown in FIG. 4) grouped together as a single logical entity.

[0062]

[0084] Bus 410, such as an internal bus (e.g., a CPU memory bus), an external bus (e.g., a Universal Serial Bus port, a Peripheral Component Interconnect Express port), or the like, may be a communication device that transfers data between components within device 400.

[0063]

[0085] For ease of explanation and to avoid ambiguity, this disclosure will collectively refer to the processor 402 and other data processing circuitry as "data processing circuitry." The data processing circuitry may be implemented entirely as hardware or as a combination of software, hardware, or firmware. In addition, the data processing circuitry may be a single, independent module or may be fully or partially combined within any other component of the device 400.

[0064]

[0086] Device 400 may further include a network interface 406 for providing wired or wireless communication with a network (e.g., the Internet, an intranet, a local area network, a mobile communication network, etc.) In some embodiments, network interface 406 may include any combination of any number of network interface controllers (NICs), radio frequency (RF) modules, transponders, transceivers, modems, routers, gateways, wired network adapters, wireless network adapters, Bluetooth adapters, infrared adapters, near field communication ("NFC") adapters, cellular network chips, etc.

[0065]

[0087] In some embodiments, device 400 may optionally further include a peripheral interface 408 for providing connection to one or more peripheral devices. As shown in Figure 4, peripheral devices may include, but are not limited to, a cursor control device (e.g., a mouse, touchpad, or touchscreen), a keyboard, a display (e.g., a cathode ray tube display, a liquid crystal display, or a light emitting diode display), a video input device (e.g., a camera or input interface coupled to a video archive), etc.

[0066]

[0088] It should be noted that a video codec (e.g., a codec that executes process 200A, 200B, 300A, or 300B) can be implemented as any combination of software or hardware modules within device 400. For example, some or all of the stages of process 200A, 200B, 300A, or 300B can be implemented as one or more software modules of device 400, such as program instructions loadable into memory 404. In another example, some or all of the stages of process 200A, 200B, 300A, or 300B can be implemented as one or more hardware modules of device 400, such as dedicated data processing circuitry (e.g., FPGA, ASIC, NPU, etc.).

[0067]

[0089] In VVC, a picture is divided into one or more tile rows and one or more tile columns. A tile is a series of CTUs that cover a rectangular area of ​​the picture. The CTUs within a tile are scanned in raster scan order within that tile. A slice consists of an integer number of complete tiles or an integer number of contiguous complete CTU rows within a tile of a picture. As a result, each vertical slice boundary is also a vertical tile boundary. The horizontal boundary of a slice is not a tile boundary, but may consist of a horizontal CTU boundary within the tile. This occurs when a tile is divided into multiple rectangular slices, each consisting of an integer number of contiguous complete CTU rows within the tile.

[0068]

[0090] In VVC, a coded video bitstream or byte stream, which is a series of bits in the form of Network Abstraction Layer (NAL) units, forms one or more coded video sequences (CVS), each of which consists of one or more coded layer video sequences (CLVS). A CLVS is a series of picture units (PUs), each of which contains exactly one coded picture.

[0069]

[0091] A PU consists of zero or one picture header (PH) NAL unit that contains as payload a picture header syntax structure, one coded picture containing one or more video coding layer (VCL) NAL units, and zero or more other non-VCL NAL units. A VCL NAL unit contains a coded slice, which consists of a slice header and slice data.

[0070]

[0092] VVC allows the quantization parameter (QP) to range from 0 to 63, and the signaling of the initial QP can be modified accordingly. If a non-zero value for slice_qp_delta is coded in the slice header, the initial value of SliceQpY is modified at the slice level. In particular, the value of init_qp_minus26 is modified to be in the range of (-26 + QpBdOffsetY) to +37. If the size of the transform block is not a power of 4, the transform coefficients are processed with modifications to the QP or QP levelScale table, rather than by multiplication by 181 / 256 (or 181 / 128), to compensate for the implicit scaling due to the transform process. For transform skip blocks, the minimum allowed QP is defined as 4, because when QP equals 4, the quantization step size becomes 1.

[0071]

[0093] In addition, the QP value can be changed per CU or per quantization group. The delta QP values ​​for the luma and chroma components can be signaled separately.

[0072]

[0094] For each luma coded block, the variable qP Y_PREV is first derived as follows: - If one or more of the following conditions are true: PY_PREV Set equal to SliceQpY: - The current quantization group is the first quantization group in the slice. - The current quantization group is the first quantization group in the tile. - Otherwise, qP Y_PREV is the luma quantization parameter Qp of the last luma coding unit in the previous quantization group in decoding order. Y Set it equal to

[0073]

[0095] Second, the variable qP Y_A is derived as follows: - qP if one or more of the following conditions are true: Y_A qP Y_PREVSet it equal to: - The left neighboring block of the current quantization group is not available. - The left neighboring block of the current quantization group and the current coding block are in different coding tree blocks (CTB). - Otherwise, qP Y_A Set LMT equal to the luma quantization parameter of the upper coded unit of the current quantization group.

[0074]

[0096] Third, the variable qP Y_B is derived as follows: - qP if one or more of the following conditions are true: Y_B qP Y_PREV Set it equal to: - The neighboring block above the current quantization group cannot be used. - The neighboring block above the current quantization group and the current coding block are in different coding tree blocks (CTB). - Otherwise, qP Y_B Set LMT equal to the luma quantization parameter of the left coded unit of the current quantization group.

[0075]

[0097] Fourth, if the current quantization group is the first quantization group in a coding tree block (CTB) row in a block, and the neighboring block above the current quantization group can be utilized, Set qPY_PRED to qPY_B, Otherwise qPY_PRED=(qPY_A+qPY_B+1)>>1

[0076]

[0098] After deriving qPY_PRED, the quantization parameter Qp' of the current luma coded block is calculated using Equation 1 below: Y can be derived: Qp' Y =((qPY_PRED+CuQpDeltaVal+64+2*QpBdOffsetY)%(64+QpBdOffsetY)) (Equation 1) where QpBdOffsetY is equal to 6*sps_bitdepth_minus8, and the variable CuQpDeltaVal specifies the difference between the quantization parameter of a luma coded block and its predicted value.

[0077]

[0099] In VVC, CuQpDeltaVal is specified as cu_qp_delta_abs*(1-2*cu_qp_delta_sign_flag), where cu_qp_delta_abs and cu_qp_delta_sign_flag are syntax elements signaled in the bitstream at the CU level. If cu_qp_delta_abs and cu_qp_delta_sign_flag are not present in the bitstream, CuQpDeltaVal can be inferred to be 0.

[0078]

[0100] The quantization parameter for the chroma coded block is Qp Y The chroma quantization parameter (Qp Cb , Qp Cr , Qp CbCr ) and the luma quantization parameter Qp' can be signaled in the bitstream. In VVC, the offset between the chroma quantization parameter Qp' can be calculated using Equations 2-4 below. Cb and Qp' Cr , as well as Qp', the QP for joint Cb-Cr coding. CbCr can be derived: Qp' Cb =Clip3(-QpBdOffset c ,63,qP Cb +pps_cb_qp_offset+slice_cb_qp_offset+CuQpOffset Cb )+QpBdOffset C (Equation 2) Qp' Cr =Clip3(-QpBdOffset c ,63,qP Cr +pps_cr_qp_offset+slice_cr_qp_offset+CuQpOffset Cr)+QpBdOffset C (Equation 3) Qp' CbCr =Clip3(-QpBdOffset c ,63,qP CbCr +pps_cbcr_qp_offset+slice_cbcr_qp_offset+CuQpOffset CbCr )+QpBdOffset C (Equation 4) However, qP Cb , qP Cr , and qP CbCr Qp using equations 5-8 Y can be derived from a lookup table with the clipped value input: qPi Chroma =Clip3(-QpBdOffset,63,Qp Y -QpBdOffset) (Equation 5) qP Cb =ChromaQpTable[0][qP Chroma ] (Equation 6) qP Cr =ChromaQpTable[1][qP Chroma ] (Equation 7) qP CbCr =ChromaQpTable[2][qP Chroma ] (Equation 8)

[0079]

[0101] CuQpOffset if cu_chroma_qp_offset_flag is equal to 0 Cb , CuQpOffset Cr、 and CuQpOffset CbCr is set to 0 and can be derived using equations 9-11 if cu_chroma_qp_offset_flag is equal to 1: CuQpOffset Cb =cb_qp_offset_list[cu_chroma_qp_offset_idx] (Equation 9) CuQpOffset Cr=cr_qp_offset_list[cu_chroma_qp_offset_idx] (Equation 10) CuQpOffset CbCr =joint_cbcr_qp_offset_list[cu_chroma_qp_offset_idx] (Equation 11) However, cu_chroma_qp_offset_flag and cu_chroma_qp_offset_idx are syntax elements signaled in the bitstream.

[0080]

[0102] As discussed above, cu_qp_delta_abs and cu_qp_delta_sign_flag are signaled to derive CuQpDeltaVal, which can be used to derive the QP. CuQpOffset, which can be used to derive the chroma QP. Cb , CuQpOffset Cr , and CuQpOffset CbCr To derive cu_chroma_qp_offset_flag, cu_chroma_qp_offset_idx, cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i] are signaled.

[0081]

[0103] The following is an introduction to the signaling process of the relevant syntax: First, as shown in Figure 5, which shows an example PPS syntax for CU delta QP, cu_qp_delta_enabled_flag, cu_qp_delta_subdiv, cu_chroma_qp_offset_enabled_flag, and cu_chroma_qp_offset_subdiv can be signaled within a Picture Parameter Set (PPS).

[0082]

[0104] The variables IsCuQpDeltaCoded and IsCuChromaQpOffsetCoded, the quantization parameter group position, and the variables qgOnY and qgOnC can then be derived at the coding tree level, as shown in FIG. 6, which illustrates an example coding tree syntax for CU delta QP.

[0083]

[0105] Furthermore, as shown in Figure 7, which shows an exemplary transform unit level syntax for CU delta QP, cu_qp_delta_abs / cu_qp_delta_sign_flag and cu_chroma_qp_offset_flag / cu_chroma_qp_offset_idx are signaled in the transform unit, provided that IsCuQpDeltaCoded and IsCuChromaQpOffsetCoded are derived at the coded unit level.

[0084]

[0106] In the example of Figure 5, cu_qp_delta_subdiv specifies the maximum cbSubdiv value for coded units that carry cu_qp_delta_abs and cu_qp_delta_sign_flag, and cu_chroma_qp_offset_subdiv specifies the maximum cbSubdiv value for coded units that carry cu_chroma_qp_offset_flag. cbSubdiv is a variable whose value is related to the size of the coded unit. Smaller coded units have larger cbSubdiv values. Splitting a coded unit into multiple sub-coded units increases the value of cbSubdiv. The range of values ​​for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv depends on a variable called MaxMttDepthY, which is derived based on the slice level and slice type. MaxMttDepthY=slice_max_mtt_hierarchy_depth_luma (Equation 12) However, slice_max_mtt_hierarchy_depth_luma is signaled in the slice header, as shown in FIG. 8, which shows an example slice header syntax.

[0085]

[0107] As explained above, two syntax elements, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv, are signaled within the PPS level to determine the maximum depth of a coded unit that can carry cu_qp_delta_abs / cu_qp_delta_sign_flag and cu_chroma_qp_offset_flag. However, the value ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv depend on the variable MaxMttDepthY, which is derived based on the slice level and slice type. Therefore, the PPS level syntax elements depend on the slice level syntax.

[0086]

[0108] In the bitstream syntax structure, the PPS is at a higher level than the slice level, and the PPS syntax comes before the slice syntax. In a decoder, when parsing a low-level syntax, it can refer to the values ​​of the high-level syntax. However, when parsing a high-level syntax, it cannot refer to the values ​​of the low-level syntax. Therefore, in current VVC techniques, the dependency of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv on the slice header syntax causes a logical problem that needs to be resolved.

[0087]

[0109] To address the above problems, various embodiments of the present disclosure provide solutions. In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv can be moved to the slice header after slice_max_mtt_hierarchy_depth_luma is signaled. As a result, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are no longer PPS-level syntax elements. An example of slice header syntax is shown in Figure 9 (e.g., element 901).

[0088]

[0110] In the example shown in Figure 9, the cu_qp_delta_enabled_flag and cu_chroma_qp_offset_enabled_flag are signaled in the PPS. In some embodiments, the cu_qp_delta_enabled_flag and cu_chroma_qp_offset_enabled_flag may be signaled in the slice header as shown in Figure 10 (e.g., element 1001).

[0089]

[0111] In the example shown in Figure 10, the ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv can be determined as follows: For example, the value range of cu_qp_delta_subdiv can be specified as follows: If slice_type is equal to I, the value of cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+MaxMttDepthY) inclusive. Otherwise (slice_type is not equal to I), the value of cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+MaxMttDepthY). If not present, it can be inferred that the value of cu_qp_delta_subdiv is equal to 0.

[0090]

[0112] The value range of cu_chroma_qp_offset_subdiv can be specified as follows: If slice_type is equal to I, the value of cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+MaxMttDepthY). Otherwise (slice_type is not equal to I), the value of cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+MaxMttDepthY). If not present, it can be inferred that the value of cu_chroma_qp_offset_subdiv is equal to 0.

[0091]

[0113] In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are moved to the picture header, and at the same time the syntax elements used to derive MaxMttDepthY are also moved to the picture header, so that the ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are independent of slice-level syntax.

[0092]

[0114] Since one picture may contain multiple slices with different slice types, inter and intra, in this embodiment, cu_qp_delta_subdiv is divided into two syntax elements, namely, ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice, and cu_chroma_qp_offset_subdiv is divided into two syntax elements, namely, ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice. ph_cu_qp_delta_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_intra_slice are for intra slices in the current picture, and ph_cu_qp_delta_subdiv_inter_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice are for inter slices in the current picture. Similarly, two syntax elements, ph_max_mtt_hierarchy_depth_intra_slice_luma and ph_max_mtt_hierarchy_depth_inter_slice, are signaled for MaxMttDepthY of intra slices and inter slices.

[0093]

[0115] An example of picture header syntax is shown in Table 11 in Figure 11. As shown in Table 11, ph_cu_qp_delta_subdiv_intra_slice (e.g., element 1101), ph_cu_chroma_qp_offset_subdiv_intra_slice (e.g., element 1102), ph_cu_qp_delta_subdiv_inter_slice (e.g., element 1103), and ph_cu_chroma_qp_offset_subdiv_inter_slice (e.g., element 1104) are shown in italics and gray.

[0094]

[0116] For intra slices, ph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv value of coded units within an intra slice that convey cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_slice is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma). If not present, the value of ph_cu_qp_delta_subdiv_intra_slice can be inferred to be equal to 0.

[0095]

[0117] ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdiv value of a coded unit within an intra slice that conveys cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_intra_slice is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma). If not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice can be inferred to be equal to 0.

[0096]

[0118] In the disclosed embodiment, ph_max_mtt_hierarchy_depth_intra_slice_luma is signaled in the picture header and specifies the maximum hierarchical depth of a coding unit resulting from the multi-type tree partitioning of a quadtree leaf in a slice with sh_slice_type equal to "I" (i.e., an intra-predicted slice). CtbLog2SizeY and MinQtLog2SizeIntraY are derived using the following equations 13-15, where CtbLog2SizY represents the size of the luma coding tree block of a coding tree unit in a slice with slice_type equal to "I" (i.e., an intra-predicted slice), and MinQtLog2SizeIntraY represents the minimum size, in luma samples, of a luma leaf block resulting from the quadtree partitioning of a coding tree unit in a slice with slice_type equal to "I". CtbLog2SizeY=sps_log2_ctu_size_minus5+5 (Equation 13) MinQtLog2SizeIntraY=sps_log2_diff_min_qt_min_cb_intra_slice_luma+MinCbLog2SizeY (Equation 14) MinCbLog2SizeY=sps_log2_min_luma_coding_block_size_minus2+2 (Equation 15)

[0097]

[0119] sps_log2_ctu_size_minus5, sps_log2_diff_min_qt_min_cb_intra_slice_luma, and sps_log2_min_luma_coding_block_size_minus2 are syntax elements signaled within the SPS.

[0098]

[0120] The variable CuQpDeltaSubdiv is derived as the maximum cbSubdiv value of coded units that carry cu_qp_delta_abs and cu_qp_delta_sign_flag, and the variable CuChromaQpOffsetSubdiv is derived as the maximum cbSubdiv value of coded units that carry cu_chroma_qp_offset_flag. These two variables are derived as Equation 16 and Equation 17, respectively. CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_intra_slice (Equation 16) CuChromaQpOffsetSubdiv=ph_cu_chroma_qp_offset_subdiv_intra_slice (Equation 17)

[0099]

[0121] For inter-slices, ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv value of coded units within an inter-slice that carry cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_inter_slice can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice). If not present, the value of ph_cu_qp_delta_subdiv_inter_slice can be inferred to be equal to 0. ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdiv value of coded units within an inter-slice that carry cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_inter_slice is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice). If it is not present, it can be inferred that the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is equal to 0.

[0100]

[0122] ph_max_mtt_hierarchy_depth_inter_slice can be signaled in the picture header and specifies the maximum hierarchical depth of a coding unit resulting from the multi-type tree partitioning of quadtree leaves in slices with sh_slice_type not equal to 'I' (i.e., inter-predicted slices with slice_type equal to 'P' or 'B'). CtbLog2SizY and MinQtLog2SizeInterY are derived using the following equations 18 to 20, where CtbLog2SizY represents the size of the luma coding tree block of a coding tree unit in slices with slice_type not equal to 'I' (i.e., inter-predicted slices with slice_type equal to 'P' or 'B'), and MinQtLog2SizeInterY represents the minimum size, in luma samples, of a luma leaf block resulting from the quadtree partitioning of coding tree units in slices with slice_type not equal to 'I'. CtbLog2SizeY=sps_log2_ctu_size_minus5+5 (Equation 18) MinQtLog2SizeInterY=sps_log2_diff_min_qt_min_cb_inter_slice_luma+MinCbLog2SizeY (Equation 19) MinCbLog2SizeY=sps_log2_min_luma_coding_block_size_minus2+2 (Equation 20)

[0101]

[0123] sps_log2_ctu_size_minus5, sps_log2_diff_min_qt_min_cb_inter_slice_luma, and sps_log2_min_luma_coding_block_size_minus2 are syntax elements signaled within the SPS.

[0102]

[0124] The variable CuQpDeltaSubdiv is derived as the maximum cbSubdiv value of the coded units that carry cu_qp_delta_abs and cu_qp_delta_sign_flag, and the variable CuChromaQpOffsetSubdi is derived as the maximum cbSubdiv value of the coded units that carry cu_chroma_qp_offset_flag. These two variables are derived as Equation 21 and Equation 22, respectively. CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_inter_slice (Equation 21) CuChromaQpOffsetSubdiv=ph_cu_chroma_qp_offset_subdiv_inter_slice (Equation 22)

[0103]

[0125] In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may both be signaled at the PPS level and in the slice header. For example, pps_cu_qp_delta_subdiv and pps_cu_chroma_qp_offset_subdiv are signaled in the PPS syntax as shown in Figure 12 (e.g., elements 1201 and 1202). Slice_cu_qp_delta_subdiv and slice_cu_chroma_qp_offset_subdiv are also signaled in the slice header as shown in Figure 13 (e.g., element 1301).

[0104]

[0126] In some embodiments, the range of pps_cu_qp_delta_subdiv and pps_cu_chroma_qp_offset_subdiv depends on the syntax of the Sequence Parameter Set (SPS), as shown in the example below. In this example, the value range of pps_cu_qp_delta_subdiv is specified as follows: The value of pps_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+SpsMaxMttDepthY). If not present, the value of pps_cu_qp_delta_subdiv can be inferred to be equal to 0. The value range of pps_cu_chroma_qp_offset_subdiv is specified as follows: The value of pps_cu_chroma_qp_offset_subdiv can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+SpsMaxMttDepthY). If not present, the value of pps_cu_chroma_qp_offset_subdiv can be inferred to be equal to 0.

[0105]

[0127] When ctbLog2SizeY is defined, MinQtLog2SizeY and SpsMaxMttDepthY can be derived as follows:

[0106]

[0128] In one way, MinQtLog2SizeY is: min(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) or max(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) It can be derived as:

[0107]

[0129] It will be appreciated that MinQtLog2SizeIntraY and MinQtLog2SizeIntraY can be derived using a variety of techniques as defined in VVC Draft 6.

[0108]

[0130] Alternatively, the value of MinQtLog2SizeY can be derived based on the following equation 23: MinQtLog2SizeY=sps_log2_diff_min_qt_min_cb_luma+MinCbLog2SizeY (Equation 23)

[0109]

[0131] 14 (e.g., element 1401). It will be appreciated that MinCbLog2SizeY can be derived using various techniques, such as those specified in VVC Draft 6.

[0110]

[0132] Regarding SpsMaxMttDepth, one way to derive SpsMaxMttDepthY is as follows: min(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) or max(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) However, sps_max_mtt_hierarchy_depth_intra_slice_luma and sps_max_mtt_hierarchy_depth_inter_slice can be signaled within the SPS.

[0111]

[0133] Alternatively, the value of SpsMaxMttDepthY can be derived as follows: SpsMaxMttDepthY=sps_max_mtt_depth_luma (Equation 24) However, sps_max_mtt_depth_luma may be signaled within the SPS as shown in FIG. 14 (eg, element 1402).

[0112]

[0134] In the above example, the PPS syntax elements pps_cu_qp_delta_subdiv and pps_cu_chroma_qp_offset_subdiv depend on the SPS syntax. Such a parsing dependency between the PPS and the SPS may be undesirable. To address this dependency issue, some embodiments may specify a range of values ​​for pps_cu_qp_delta_subdiv as follows:

[0113]

[0135] The value of pps_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+ppsMaxMttDepthY). If it is not present, it can be inferred that the value of pps_cu_qp_delta_subdiv is equal to 0.

[0114]

[0136] The value range of pps_cu_chroma_qp_offset_subdiv can be specified as follows: The value of pps_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+ppsMaxMttDepthY). If it is not present, the value of pps_cu_chroma_qp_offset_subdiv can be inferred to be equal to 0.

[0115]

[0137] CtbLog2SizeY, MinQtLog2SizeY, and ppsMaxMttDepthY are derived as follows: CtbLog2SizeY=pps_log2_ctb_size (Equation 25) MinQtLog2SizeY=pps_log2_min_qt (Equation 26) ppsMaxMttDepthY=pps_max_mtt_depth_luma (Equation 27)

[0116]

[0138] pps_log2_ctb_size, pps_log2_min_qt, and pps_max_mtt_depth_luma may be signaled within the PPS as shown in FIG. 15 (eg, element 1501).

[0117]

[0139] In the above example, the range of slice_cu_qp_delta_subdiv and slice_cu_chroma_qp_offset_subdiv depends on the syntax of the slice header. For example, the value range of slice_cu_qp_delta_subdiv can be specified as follows: If slice_type is equal to I, the value of slice_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+SliceMaxMttDepthY). Otherwise (slice_type is not equal to I), the value of slice_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+SliceMaxMttDepthY). If not present, the value of slice_cu_qp_delta_subdiv can be inferred to be equal to 0 or pps_cu_qp_delta_subdiv.

[0118]

[0140] The value range of slice_cu_chroma_qp_offset_subdiv can be specified as follows: If slice_type is equal to I, the value of slice_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+SliceMaxMttDepthY). Otherwise (slice_type is not equal to I), the value of slice_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+SliceMaxMttDepthY). If not present, the value of slice_cu_chroma_qp_offset_subdiv can be inferred to be equal to 0 or pps_cu_chroma_qp_offset_subdiv.

[0119]

[0141] If CtbLog2SizeY, MinQtLog2SizeIntraY, and MinQtLog2SizeInterY are defined, SliceMaxMttDepthY is SliceMaxMttDepthY=slice_max_mtt_hierarchy_depth_luma (Equation 28) It can be derived as:

[0120]

[0142] slice_max_mtt_hierarchy_depth_luma can be signaled in the slice header.

[0121]

[0143] In the above example, cu_qp_delta_subdiv can be inferred to be slice_cu_qp_delta_subdiv, or cu_qp_delta_subdiv can be inferred to be pps_cu_qp_delta_subdiv first, and if slice_cu_qp_delta_subdiv exists, slice_cu_qp_delta_subdiv overrides it, and cu_qp_delta_subdiv can be inferred to be slice_cu_qp_delta_subdiv. The value of cu_qp_delta_subdiv is Qp Y can be used to derive

[0122]

[0144] Furthermore, cu_chroma_qp_offset_subdiv can be inferred to be slice_cu_chroma_qp_offset_subdiv, or cu_chroma_qp_offset_subdiv can be inferred to be pps_cu_chroma_qp_offset_subdiv first, and if slice_cu_chroma_qp_offset_subdiv exists, slice_cu_chroma_qp_offset_subdiv overrides it, and cu_chroma_qp_offset_subdiv can be inferred to be slice_cu_chroma_qp_offset_subdiv. The value of cu_chroma_qp_offset_subdiv is Qp Cb , Qp Cr , Q.P. CbCr can be used to derive

[0123]

[0145] In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may both be signaled at the SPS level and in the slice header. sps_cu_qp_delta_subdiv and sps_cu_chroma_qp_offset_subdiv may be signaled in the SPS as shown in Figure 16 (e.g., element 1601), and slice_cu_qp_delta_subdiv and slice_cu_chroma_qp_offset_subdiv are signaled in the slice header as shown in Figure 17 (e.g., element 1701).

[0124]

[0146] In some embodiments, the range of sps_cu_qp_delta_subdiv and sps_cu_chroma_qp_offset_subdiv depends on the syntax of the SPS. For example, the value range of sps_cu_qp_delta_subdiv can be specified as follows: The value of sps_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+SpsMaxMttDepthY). If not present, the value of sps_cu_qp_delta_subdiv can be inferred to be equal to 0. The value range of sps_cu_chroma_qp_offset_subdiv is specified as follows: The value of sps_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+SpsMaxMttDepthY). If not present, the value of sps_cu_chroma_qp_offset_subdiv can be inferred to be equal to 0.

[0125]

[0147] If ctbLog2SizeY is defined, MinQtLog2SizeY and SpsMaxMttDepthY can be derived as follows:

[0126]

[0148] In some ways, MinQtLog2SizeY is min(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) or max(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) It can be derived as:

[0127]

[0149] However, MinQtLog2SizeIntraY and MinQtLog2SizeIntraY can be derived using various techniques as specified in VVC Draft 6.

[0128]

[0150] Alternatively, the value of MinQtLog2SizeY can be derived using Equation 29 below. MinQtLog2SizeY=sps_log2_diff_min_qt_min_cb_luma+MinCbLog2SizeY (Equation 29)

[0129]

[0151] sps_log2_diff_min_qt_min_cb_luma may be signaled within the SPS as shown in Figure 18 (e.g., element 1801). It will be appreciated that MinCbLog2SizeY may be derived using various techniques such as those specified in VVC Draft 6.

[0130]

[0152] Regarding SpsMaxMttDepthY, in a certain way, SpsMaxMttDepthY is min(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) or max(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) It can be derived as:

[0131]

[0153] sps_max_mtt_hierarchy_depth_intra_slice_luma and sps_max_mtt_hierarchy_depth_inter_slice can be signaled within the SPS.

[0132]

[0154] Alternatively, SpsMaxMttDepthY is SpsMaxMttDepthY=sps_max_mtt_depth_luma (Equation 30) It can be derived as:

[0133]

[0155] sps_max_mtt_depth_luma may be signaled within the SPS as shown in FIG. 18 (eg, element 1802).

[0134]

[0156] Furthermore, in the above example, the range of slice_cu_qp_delta_subdiv and slice_cu_chroma_qp_offset_subdiv depends on the syntax of the slice header. For example, the value range of slice_cu_qp_delta_subdiv can be specified as follows: If slice_type is equal to I, the value of slice_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+SliceMaxMttDepthY). Otherwise (slice_type is not equal to I), the value of slice_cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+SliceMaxMttDepthY). If not present, it can be inferred that the value of slice_cu_qp_delta_subdiv is equal to 0 or sps_cu_qp_delta_subdiv.

[0135]

[0157] The value of slice_cu_chroma_qp_offset_subdiv can be specified as follows: If slice_type is equal to I, the value of slice_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+SliceMaxMttDepthY). Otherwise (slice_type is not equal to I), the value of slice_cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+SliceMaxMttDepthY). If not present, the value of slice_cu_chroma_qp_offset_subdiv can be inferred to be equal to 0 or sps_cu_chroma_qp_offset_subdiv.

[0136]

[0158] If CtbLog2SizeY, MinQtLog2SizeIntraY, and MinQtLog2SizeInterY are defined, SliceMaxMttDepthY is SliceMaxMttDepthY=slice_max_mtt_hierarchy_depth_luma (Equation 31) It can be derived as:

[0137]

[0159] slice_max_mtt_hierarchy_depth_luma can be signaled in the slice header.

[0138]

[0160] In the above example, cu_qp_delta_subdiv can be inferred to be slice_cu_qp_delta_subdiv, or cu_qp_delta_subdiv can be inferred to be sps_cu_qp_delta_subdiv first, and if slice_cu_qp_delta_subdiv exists, slice_cu_qp_delta_subdiv overrides it, and cu_qp_delta_subdiv can be inferred to be slice_cu_qp_delta_subdiv. Cu_qp_delta_subdiv is Qp Y can be used to derive

[0139]

[0161] Furthermore, in the above example, cu_chroma_qp_offset_subdiv can be inferred to be slice_cu_chroma_qp_offset_subdiv. Alternatively, cu_chroma_qp_offset_subdiv can be inferred to be sps_cu_chroma_qp_offset_subdiv first, and if slice_cu_chroma_qp_offset_subdiv exists, slice_cu_chroma_qp_offset_subdiv overrides it, and cu_chroma_qp_offset_subdiv can be inferred to be slice_cu_chroma_qp_offset_subdiv. Cu_chroma_qp_offset_subdiv is the Qp Cb , Qp Cr , Q.P. CbCr can be used to derive

[0140]

[0162] In some embodiments, the syntax of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be signaled at the PPS level, but the range restrictions of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be modified so that they are independent of the slice syntax.

[0141]

[0163] As an example, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be signaled within a PPS as shown in Figure 5. The value range of cu_qp_delta_subdiv may be specified as follows: The range of cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_qp_delta_subdiv may be inferred to be equal to 0. The value range of cu_chroma_qp_offset_subdiv may be specified as follows: The value of cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_chroma_qp_offset_subdiv may be inferred to be equal to 0.

[0142]

[0164] If ctbLog2SizeY is defined, MinQtLog2SizeY and MaxMttDepthY can be inferred on the SPS level. For example, MaxMttDepthY is min(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) or max(sps_max_mtt_hierarchy_depth_intra_slice_luma, sps_max_mtt_hierarchy_depth_inter_slice) It can be derived as:

[0143]

[0165] sps_max_mtt_hierarchy_depth_intra_slice_luma and sps_max_mtt_hierarchy_depth_inter_slice can be signaled within the SPS.

[0144]

[0166] Alternatively, MaxMttDepthY can be MaxMttDepthY=sps_max_mtt_depth_luma It can be derived as:

[0145]

[0167] sps_max_mtt_depth_luma may be signaled within the SPS as shown in FIG. 19 (eg, element 1901).

[0146]

[0168] In some cases, MinQtLog2SizeY min(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) or max(MinQtLog2SizeIntraY, MinQtLog2SizeInterY) It can be derived as:

[0147]

[0169] It will be appreciated that MinQtLog2SizeIntraY and MinQtLog2SizeIntraY can be derived using a variety of techniques as defined in VVC Draft 6.

[0148]

[0170] Alternatively, the value of MinQtLog2SizeY can be derived based on the following equation 32: MinQtLog2SizeY=sps_log2_diff_min_qt_min_cb_lima+MinCbLog2SizeY (Equation 32)

[0149]

[0171] sps_log2_diff_min_qt_min_cb_luma is signaled within the SPS as shown in Figure 13 (e.g., element 1301). It will be appreciated that MinCbLog2SizeY can be derived using various techniques such as those specified in VVC Draft 6.

[0150]

[0172] Based on the above example, the ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are not overridden at the slice header level.

[0151]

[0173] In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be signaled at the PPS level, but the range limits for cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be fixed so that they are independent of the slice syntax.

[0152]

[0174] For example, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be signaled within a PPS as shown in Figure 5. The value range of cu_qp_delta_subdiv may be specified as follows: The value of cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_qp_delta_subdiv may be inferred to be equal to 0. The value range of cu_chroma_qp_offset_subdiv may be specified as follows: The value of cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_chroma_qp_offset_subdiv may be inferred to be equal to 0.

[0153]

[0175] However, CtbLog2SizeY, MinQtLog2SizeY, and MaxMttDepthY can be derived in the following manner: CtbLog2SizeY / MinQtLog2SizeY / MaxMttDepthY can be specified by a profile, or CtbLog2SizeY / MinQtLog2SizeY / MaxMttDepthY can be fixed numerical values.

[0154]

[0176] Based on the above example, the ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are not overridden at the slice header level.

[0155]

[0177] In some embodiments, cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv may be signaled within the PPS as shown in Figure 5. The value range of cu_qp_delta_subdiv may be specified as follows: The value of cu_qp_delta_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_qp_delta_subdiv may be inferred to be equal to 0. The value range of cu_chroma_qp_offset_subdiv is specified as follows: The value of cu_chroma_qp_offset_subdiv is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeY+MaxMttDepthY). If not present, the value of cu_chroma_qp_offset_subdiv may be inferred to be equal to 0.

[0156]

[0178] CtbLog2SizeY, MinQtLog2SizeY, and MaxMttDepthY can be inferred on the PPS level, for example: CtbLog2SizeY=pps_log2_ctb_size (Equation 33) MinQtLog2SizeY=pps_log2_min_qt (Equation 34) MaxMttDepthY=pps_max_mtt_depth_luma (Equation 35)

[0157]

[0179] pps_log2_ctb_size, pps_log2_min_qt, and pps_max_mtt_depth_luma are signaled within the PPS as shown in FIG. 20 (eg, element 2001).

[0158]

[0180] Based on the above example, the ranges of cu_qp_delta_subdiv and cu_chroma_qp_offset_subdiv are not overridden at the slice header level.

[0159]

[0181] FIG. 21 is a flow diagram of a computer-implemented method 2100 for processing video content consistent with embodiments of the present disclosure.

[0160]

[0182] At step 2102, a depth parameter associated with the depth of the coded block may be received. The depth parameter may be, for example, a variable "MaxMttDepthY" derived from the maximum depth of the multi-type tree hierarchy of the luma block (e.g., "slice_max_mtt_hierarchy_depth_luma"). In some embodiments, "slice_max_mtt_hierarchy_depth_luma" may be signaled in a slice header associated with the coded block.

[0161]

[0183] A coded block may be associated with a slice. A slice may be associated with intra prediction or inter prediction. Depending on whether the slice is associated with intra prediction, a delta QP value or a chroma QP offset value may be determined for the slice associated with intra prediction. Alternatively, depending on whether the slice is associated with inter prediction, a delta QP value or a chroma QP offset value may be determined for the slice associated with inter prediction. For example, if "slice_type" is equal to "I" (indicating that the slice is associated with intra prediction), the value of "cu_qp_delta_subdiv" is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+MaxMttDepthY). Otherwise, if "slice_type" is not equal to "I" (indicating that the slice is associated with inter prediction), the value of "cu_qp_delta_subdiv" is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+MaxMttDepthY). Further by way of example, if "slice_type" is equal to "I", then the value of "cu_chroma_qp_offset_subdiv" is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+MaxMttDepthY). Otherwise, if "slice_type" is not equal to "I", then the value of "cu_chroma_qp_offset_subdiv" is in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+MaxMttDepthY).

[0162]

[0184] In some embodiments, depth parameters may be signaled in a picture header. It will be understood that a picture may include multiple slices. For slices related to intra prediction, corresponding delta QP values ​​or chroma QP offset values ​​may be determined for the slices related to intra prediction. For slices related to inter prediction, corresponding delta QP values ​​or chroma QP offset values ​​may be determined for the slices related to inter prediction. For example, as discussed with respect to Table 11 of FIG. 11 , ph_cu_qp_delta_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_intra_slice are signaled in the picture header to derive delta QP values ​​and chroma QP offset values ​​for slices related to inter prediction. ph_cu_qp_delta_subdiv_inter_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice are signaled in the picture header to derive delta QP values ​​and chroma QP offset values ​​for slices related to inter prediction.

[0163]

[0185] At least one of a delta quantization parameter (QP) value or a chroma QP offset value may be determined based on the depth of the coded block in step 2104. As discussed above, the delta QP value may be determined based on "cu_qp_delta_subdiv," and the chroma QP offset value may be determined based on "cu_chroma_qp_offset_subdiv," which may be determined based on the variable "MaxMttDepthY."

[0164]

[0186] In step 2106, a luma QP value may be derived based on the determined delta QP value, and a chroma QP value may be derived based on the determined chroma QP offset value.

[0165]

[0187] In step 2108, the coded block may be processed based on the derived luma QP value and the derived chroma QP value.

[0166]

[0188] In some embodiments, a non-transitory computer-readable storage medium containing instructions is also provided, which may be executed by an apparatus (such as the disclosed encoders and decoders) to perform the above-described methods. Common non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, magnetic tape or any other magnetic data storage medium, CD-ROMs, any other optical data storage medium, any physical medium with a pattern of holes, RAM, PROMs and EPROMs, flash EPROMs or any other flash memory, NVRAM, cache, registers, any other memory chip or cartridge, and networked versions thereof. An apparatus may include one or more processors (CPUs), input / output interfaces, network interfaces, and / or memory.

[0167]

[0189] Embodiments may be further described using the following clauses: 1. A computer-implemented method comprising: receiving a bitstream containing coded video data; determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter; and Determining at least one of the delta QP value or the chroma QP offset value according to one or more second parameters. A method comprising: 2. Determining a first parameter of the coding block includes: Determining whether the coded block is associated with an intra-predicted slice or an inter-predicted slice; and In response to the coded block being associated with an intra-predicted slice, determining the first parameter to be a parameter associated with the intra-predicted slice; or determining the first parameter to be a parameter associated with the inter-prediction slice in response to the coded block being associated with the inter-prediction slice; 2. The method according to clause 1, comprising: 3. The method of clause 1, wherein the first parameter is signaled in a slice header associated with the coded block. 4. The method of clause 1, wherein the first parameter is signaled in a picture header associated with the coded block. 5. Determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and Processing coded blocks based on luma QP values ​​and chroma QP values 2. The method of clause 1, further comprising: 6. A system for processing video content, comprising: a memory for storing a set of instructions; and at least one processor, the at least one processor comprising: receiving a bitstream containing coded video data; determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter; and Determining at least one of the delta QP value or the chroma QP offset value according to one or more second parameters. a system configured to execute a set of instructions to cause the system to: 7. At least one processor: Determining whether the coded block is associated with an intra-predicted slice or an inter-predicted slice; and In response to the coded block being associated with an intra-predicted slice, determining the first parameter to be a parameter associated with the intra-predicted slice; or determining the first parameter to be a parameter associated with the inter-prediction slice in response to the coded block being associated with the inter-prediction slice; 7. The system of claim 6, configured to execute a set of instructions to cause the system to further: 8. The system of clause 6, wherein the first parameter is signaled in a slice header associated with the coded block. 9. The system of clause 6, wherein the first parameter is signaled in a picture header associated with the coded block. 10. At least one processor: determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and Processing coded blocks based on luma QP values ​​and chroma QP values 7. The system of claim 6, configured to execute a set of instructions to cause the system to further: 11. A non-transitory computer-readable medium storing instructions executable by at least one processor of a computer system, the execution of the instructions comprising: receiving a bitstream containing coded video data; determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter; and Determining at least one of the delta QP value or the chroma QP offset value according to one or more second parameters. A non-transitory computer-readable medium that causes a computer system to perform a method including: 12. How to Determining whether the coded block is associated with an intra-predicted slice or an inter-predicted slice; and In response to the coded block being associated with an intra-predicted slice, determining the first parameter to be a parameter associated with the intra-predicted slice; or determining the first parameter to be a parameter associated with the inter-prediction slice in response to the coded block being associated with the inter-prediction slice; 12. The non-transitory computer-readable medium of clause 11, further comprising: 13. The non-transitory computer-readable medium of clause 11, wherein the first parameter is signaled in a slice header associated with the coded block. 14. The non-transitory computer-readable medium of clause 11, wherein the first parameter is signaled in a picture header associated with the coded block. 15. The method is determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and Processing coded blocks based on luma QP values ​​and chroma QP values 12. The non-transitory computer-readable medium of clause 11, further comprising:

[0168]

[0190] It should be noted that relational terms such as "first" and "second" herein are used merely to distinguish one entity or operation from another and do not require or imply any actual relationship or order between those entities or operations. Furthermore, terms such as "comprise," "have," "contain," and "include," and other similar forms, are intended to be equivalent in meaning and are open-ended in that the items following any one of these terms are not intended to be an exhaustive list of such items or to be limited only to the items they list.

[0169]

[0191] As used herein, unless otherwise specified, the word "or" includes all possible combinations unless impracticable. For example, if a database is stated to include A or B, the database can include A or B, or A and B, unless otherwise specified or impracticable. As a second example, if a database is stated to include A, B, or C, the database can include A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C, unless otherwise specified or impracticable.

[0170]

[0192] It will be understood that the above-described embodiments can be implemented by hardware or software (program code), or a combination of hardware and software. If implemented by software, the software can be stored in the above-described computer-readable medium. The software, when executed by a processor, can perform the disclosed methods. The computational units and other functional units described in this disclosure can be implemented by hardware or software, or a combination of hardware and software. Those skilled in the art will also understand that multiple of the above-described modules / units can be combined into one module / unit, and that each of the above-described modules / units can be further divided into multiple sub-modules / sub-units.

[0171]

[0193] In the foregoing specification, embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. Certain adaptations and modifications to the described embodiments may be made. Other embodiments may become apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims. The order of steps depicted in the figures is for illustrative purposes only and is not intended to be limited to the particular order of steps. As such, one skilled in the art will recognize that steps can be performed in different orders while implementing the same method.

[0172]

[0194] Although illustrative embodiments have been disclosed in the drawings and herein, many variations and modifications to those embodiments may be made. Accordingly, although specific terms have been employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. 1. A method of decoding a bitstream to output one or more pictures for a video stream, comprising: receiving a bitstream containing coded video data; and Decoding one or more pictures using coded information of the bitstream. wherein said decoding comprises: determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter, wherein each of the one or more second parameters includes an intra-slice component and an inter-slice component; and determining at least one of the delta QP value or the chroma QP offset value according to the one or more second parameters; Including, the second parameter related to the delta QP value is divided into a delta QP intra-slice component and a delta QP inter-slice component; the second parameter related to a chroma QP offset value is divided into a chroma QP offset intra-slice component and a chroma QP offset inter-slice component; the delta QP intra slice component and the chroma QP offset intra slice component are for an intra slice; The method, wherein the delta QP interslice factor and the chroma QP offset interslice factor are for interslice.

2. The method of claim 1 , wherein the first parameter is signaled in at least one of a slice header or a picture header associated with the coded block.

3. determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and processing the coded block based on the luma QP value and the chroma QP value; The method of claim 1 further comprising:

4. the size of the luma coding treeblock per coding tree, the minimum size of luma samples in a luma reef block resulting from the quadtree decomposition of the coding tree units within an intra-slice or inter-slice; and the maximum hierarchical depth of a coding unit resulting from a multitype tree split of a leaf of a quadtree within the intra-slice or the inter-slice; The method of claim 1 , further comprising determining a range of maximum values ​​of the first parameter based on:

5. The method of claim 1 , further comprising de-packetizing the bitstream before feeding it to a binary decoding stage.

6. 2. The method of claim 1, wherein the bitstream comprises coded syntax elements coded using entropy coding based on one or more of a plurality of contexts used in binary entropy coding.

7. The method of claim 1 , further comprising performing binary decoding to determine the first parameter.

8. 1. A method for encoding a video sequence into a bitstream, the method comprising: receiving a video sequence; encoding one or more pictures of the video sequence; and Generating the bitstream wherein said encoding comprises: determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter, wherein each of the one or more second parameters includes an intra-slice component and an inter-slice component; and determining at least one of the delta QP value or the chroma QP offset value according to the one or more second parameters; Including, the second parameter related to the delta QP value is divided into a delta QP intra-slice component and a delta QP inter-slice component; the second parameter related to a chroma QP offset value is divided into a chroma QP offset intra-slice component and a chroma QP offset inter-slice component; the delta QP intra slice component and the chroma QP offset intra slice component are for an intra slice; The method, wherein the delta QP interslice factor and the chroma QP offset interslice factor are for interslice.

9. The method of claim 8 , wherein the first parameter is signaled in at least one of a slice header or a picture header associated with the coded block.

10. determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and processing the coded block based on the luma QP value and the chroma QP value; The method of claim 8 further comprising:

11. the size of the luma coding treeblock per coding tree, the minimum size of luma samples in a luma reef block resulting from the quadtree decomposition of the coding tree units within an intra-slice or inter-slice; and the maximum hierarchical depth of a coding unit resulting from a multitype tree split of a leaf of a quadtree within the intra-slice or the inter-slice; The method of claim 8 , further comprising determining a range of maximum values ​​of the first parameter based on:

12. The method of claim 8 , further comprising encoding the syntax element using entropy coding based on one or more of a plurality of contexts used in binary entropy coding.

13. The method of claim 8 , further comprising performing binary encoding to determine the first parameter.

14. 1. A method for storing a bitstream of a video sequence, said method comprising: receiving a video sequence; encoding one or more pictures of the video sequence; generating a bitstream; and storing the bitstream on a non-transitory computer-readable storage medium; wherein said encoding comprises: determining a first parameter of the coded block; determining one or more second parameters related to a delta quantization parameter (QP) value or a chroma QP offset value according to the first parameter, wherein each of the one or more second parameters includes an intra-slice component and an inter-slice component; and determining at least one of the delta QP value or the chroma QP offset value according to the one or more second parameters; Including, the second parameter related to the delta QP value is divided into a delta QP intra-slice component and a delta QP inter-slice component; the second parameter related to a chroma QP offset value is divided into a chroma QP offset intra-slice component and a chroma QP offset inter-slice component; the delta QP intra slice component and the chroma QP offset intra slice component are for an intra slice; The method, wherein the delta QP interslice factor and the chroma QP offset interslice factor are for interslice.

15. The method of claim 14 , wherein the first parameter is encoded in at least one of a slice header or a picture header associated with the coded block.

16. The encoding step comprises: determining a luma QP value based on the delta QP value; determining a chroma QP value based on the chroma QP offset value; and processing the coded block based on the luma QP value and the chroma QP value; The method of claim 14 further comprising:

17. The encoding step comprises: the size of the luma coding treeblock per coding tree, the minimum size of luma samples in a luma reef block resulting from the quadtree decomposition of the coding tree units within an intra-slice or inter-slice; and the maximum hierarchical depth of a coding unit resulting from a multitype tree split of a leaf of a quadtree within the intra-slice or the inter-slice; 15. The method of claim 14, further comprising determining a range of maximum values ​​of the first parameter based on:

18. 15. The method of claim 14, wherein the bitstream comprises coded syntax elements coded using entropy coding based on one or more of a plurality of contexts used in binary entropy coding.

19. The method of claim 14 , wherein the encoding further comprises performing a binary encoding to determine the first parameter.

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