EP-4740459-A1 - DECODER-SIDE INTRA MODE DERIVATION MERGE

Abstract

In accordance with example embodiments of the invention there is at least a method and apparatus to perform forming an intra prediction block in accordance to a merged decoder side intra mode derivation process, where the merged decoder side intra mode derivation process includes: forming an intra prediction for a current block of video data by means of blending a number of predictors, where at least some of the predictors are obtained by determining intra prediction modes, where the intra prediction modes are determined based on a decoder side intra mode derivation process applied to at least one different block.

Inventors

• BLASI, Saverio
• ZUPANCIC, Ivan
• LAINEMA, JANI

Assignees

• Nokia Technologies Oy

Dates

Publication Date

20260513

Application Date

20240529

Claims (20)

1. 1. An apparatus, comprising: at least one processor; and at least one non-transitory memory storing instructions, that when executed by the at least one processor, cause the apparatus at least to: form an intra prediction block in accordance to a merged decoder side intra mode derivation process, where the merged decoder side intra mode derivation process includes: forming an intra prediction for a current block of video data by means of blending a number of predictors, where at least some of the predictors are obtained by determining intra prediction modes, where the intra prediction modes are determined based on a decoder side intra mode derivation process applied to at least one different block.
2. 2. The apparatus of claim 1 wherein the at least one different block comprises at least one neighbouring block.
3. 3. The apparatus of claim 1, wherein signalling is used to determine if the intra prediction for the current block should operate in accordance to a merged decoder side intra mode derivation process.
4. 4. The apparatus according to any one of claims 1-3, wherein a presence of signalling is inferred based on at least one of whether any block of the at least one different block is coded using a decoder side intra mode derivation process, or whether any block of the at least one different block is coded using a merged decoder side intra mode derivation process.
5. 5. The apparatus of claim 1, wherein the decoder side intra mode derivation process applied to the at least one block operates in dependence on the formation of a histogram of gradients.
6. 6. The apparatus according to any one of claims 1-5, wherein the formation of the histogram of gradients includes spreading a given amplitude across multiple entries in the histogram of gradients.
7. 7. The apparatus according to any one of claims 1-5, wherein based on an intra prediction mode number x being determined to have an amplitude A, the histogram of gradients is updated by adding A to the bin corresponding to mode x, and A/2 for the bins corresponding to the modes x-1 and x+1.
8. 8. The apparatus according to any preceding claim wherein a histogram of gradients is computed for the current block based on the histogram of gradients extracted from a block of the at least one different block.
9. 9. The apparatus according to any preceding claim, wherein a histogram of gradients is computed for the current block based on the intra prediction modes used in the at least one different block.
10. 10. The apparatus according to any preceding claim, wherein the histogram of gradients computed for the current block is formed of a number of amplitudes for each intra prediction mode, where the amplitude for a given intra prediction mode is computed as the average of the amplitudes for that intra prediction mode extracted from the histogram of gradients of blocks of the at least one different block.
11. 11. The apparatus of the preceding claim, where the average of the amplitudes is a weighted average, where the weights are computed depending on characteristics of the at least one different block, wherein the characteristics comprise at least one of a block size and width, or a block physical location in x and y coordinates within a frame.
12. 12. The apparatus of the preceding claim, where the average of the amplitudes is a weighted average, where the weights are computed depending on characteristics of the current block, wherein the characteristics comprise at least one of a block size and width, or a block physical location in x and y coordinates within a frame.
13. 13. The apparatus of any of the preceding claims, where a location dependency is computed for each intra prediction mode for the current block, where the location dependency is computed in dependency to the location dependency of intra prediction modes extracted from a block of the at least one different block.
14. 14. The apparatus according to any preceding claim, wherein the merged decoder side intra mode derivation process includes determining one or more blocks to merge based on the size of the blocks of the at least one different block.
15. 15. The apparatus according to any preceding claim wherein the merged decoder side intra mode derivation process includes determining one or more blocks to merge based on the location of the at least one different block with respect to the current block.
16. 16. The apparatus of claim 1, wherein the intra prediction modes and weights to use for the current block are set equal to the intra prediction modes and weights used in a block of the at least one different block coded in accordance to a decoder side intra mode derivation process.
17. 17. The apparatus of claim 1, wherein the intra prediction modes and weights to use for the current block are set equal to the intra prediction modes and weights used in a block of the at least one different block coded in accordance to a merged decoder side intra mode derivation process.
18. 18. A method, compri sing : forming an intra prediction block in accordance to a merged decoder side intra mode derivation process, where the merged decoder side intra mode derivation process includes: forming an intra prediction for a current block of video data by means of blending a number of predictors, where at least some of the predictors are obtained by determining intra prediction modes, where the intra prediction modes are determined based on a decoder side intra mode derivation process applied to at least one different block.
19. 19. The method of claim 18, wherein the at least one different block comprises at least one neighbouring block.
20. 20. The method of claim 18, wherein signalling is used to determine if the intra prediction for the current block should operate in accordance to a merged decoder side intra mode derivation process.

Description

DECODER-SIDE INTRA MODE DERIVATION MERGE TECHNICAL FIELD: [0001] The teachings in accordance with the exemplary embodiments of this invention relate generally to a new machine learning-dedicated bearer for machine learning or artificial intelligence related data exchange and, more specifically, relate to a new method and apparatus operating to at least produce an intra prediction for a given block using intra prediction. BACKGROUND: [0002] This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section. [0003] Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows: AMF access and mobility function CC cross component CCLM cross-component linear model CTU coding tree unit DIMD decoder side intra mode derivation ECM exploration coding model Intra TMP intra template matching prediction LMF location management function LUT lookup table MME mobility management entity MPM most probable modes NCE network control element PCF policy control function RAN random access network SGW serving gateway SMF session management function TM template matching UDM unified data management [0004] Brief Description of Prior Developments [0005] Decoder side intra mode derivation (DIMD) for video codecs uses a method to determine the Intra mode of the current block using directionality of the texture of the neighboring reconstructed samples located in a template region at top, top-left, and left sides of the current block. In DIMD, one (or more) intra modes and their corresponding weight factors are derived first. Then, predictors are generated for these intra modes, and also for the Planar mode. A final intra prediction for the current block is generated by combining these predictors by means of sample-wise or uniform weighting, using the derived weights. [0006] In an existing DIMD method, it is highly unlikely that two blocks with different neighbouring reference samples will produce identical DIMD histograms of gradients (e.g., amplitudes), and correspondingly identical directional modes and weights in the blending process. However, in some cases (e.g., different neighbouring blocks being part of the same object or texture) it may be beneficial to encode two or more neighbouring blocks using DIMD, with the same directional intra modes and weights. Furthermore, even if the same directional modes and weights are used for the neighbouring blocks, in the existing DIMD method they would be redundantly recalculated during the decoding process. [0007] Example embodiments of this invention proposes at least improved operations for Decoder side intra mode derivation operations. SUMMARY: [0008] This section contains examples of possible implementations and is not meant to be limiting. [0009] In another example aspect of the invention, there is an apparatus, such as a user equipment side apparatus, comprising: at least one processor; and at least one non-transitory memory storing instructions, that when executed by the at least one processor, cause the apparatus at least to: form an intra prediction block in accordance to a merged decoder side intra mode derivation process, wherein the merged decoder side intra mode derivation process includes: forming an intra prediction for a current block of video data by means of blending a number of predictors, wherein at least some of the predictors are obtained by determining intra prediction modes, and wherein the intra prediction modes are determined based on a decoder side intra mode derivation process applied to at least one different block. [0010] In still another example aspect of the invention, there is a method, comprising: forming an intra prediction block in accordance to a merged decoder side intra mode derivation process, wherein the merged decoder side intra mode derivation process includes: forming an intra prediction for a current block of video data by means of blending a number of predictors, wherein at least some of the predictors are obtained by determining intra prediction modes, and wherein the intra prediction modes are determined based on a decoder side intra mode derivation process applied to at least one different block. [0011] A further example embodiment is an apparatus and a method comprising the apparatus and the method of the previous paragraphs, wherein the at least one different block comprises at least one neighbouring block, wherein signalling is used to determine if the prediction for the current block should operate in accordance to a merged decoder side intra mode derivation process, wherein a presence of signall