Logical intra mode naming in HEVC video coding
AssigneeSony Corporation
InventorsEhsan Maani, Ali Tabatabai, Jun Xu
Life of this patent
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Abstract
A method and apparatus of using logical mode numbers during both prediction and coding in the bit stream, such as for high efficiency video coders (HEVC). These logical intra mode numbers are sorted based on angle which as a result leads to improved coding designs with fewer and smaller look-up tables, and a small gain in coding efficiency. Furthermore, by using this type of naming, the number of most probable modes (MPMs) can be readily extended since no additional tables are required. The use of three MPMs achieves a larger gain of 0.25% and 0.31% for the AI_HE and AI_LC cases, respectively.
Claims17
An image processing apparatus, comprising:
- a computer processor;
- and
- a memory configured to store instructions, executable by the computer processor, to process blocks in an image to be generated by decoding a bit stream, wherein the computer processor is configured to:
- select candidate intra prediction modes for a current block based on a determination that (A) a first intra prediction mode for a first neighboring block adjacent to the current block is equal to a second intra prediction mode for a second neighboring block adjacent to the current block and (B) the first intra prediction mode is equal to angular mode;
- and
- execute an intra prediction based on an intra prediction mode selected from the candidate intra prediction modes, wherein
- the selection of the intra prediction mode is based on a mode number related to the intra prediction mode,
- based on the mode number that indicates 0, the first intra prediction mode is set,
- based on the mode number that indicates 1, a third intra prediction mode is set,
- the third intra prediction mode differs from the first intra prediction mode,
- based on the mode number that indicates 2, a fourth intra prediction mode is set, and
- the fourth intra prediction mode differs from the first intra prediction mode and the third intra prediction mode.
A method, comprising:
- in an image processing apparatus:
- executing a decoding process on a bit stream to obtain an image comprising a plurality of blocks;
- selecting candidate intra prediction modes for a current block of the image, based on a determination that (A) a first intra prediction mode for a first neighboring block adjacent to the current block is equal to a second intra prediction mode for a second neighboring block adjacent to the current block and (B) the first intra prediction mode is equal to angular mode;
- and
- executing an intra prediction based on an intra prediction mode selected from the candidate intra prediction modes, wherein
- the selection of the intra prediction mode is based on a mode number related to the intra prediction mode, such that
- based on the mode number that is 0, the first intra prediction mode is set,
- based on the mode number that is 1, a third intra prediction mode is set,
- the third intra prediction mode differs from the first intra prediction mode,
- based on the mode number that is 2, a fourth intra prediction mode is set, and
- the fourth intra prediction mode differs from the first intra prediction mode and the third intra prediction mode.
Dependencies are inferred from the claim text.