Two level last significant coefficient (LSC) position coding

摘要

In some examples, a video coder employs a two-level technique to code information that identifies a position within the block of transform coefficients of one of the coefficients that is a last significant coefficient (LSC) for the block according to a scanning order associated with the block of transform coefficients. For example, a video coder may code a sub-block position that identifies a position of one of the sub-blocks that includes the LSC within the block, and code a coefficient position that identifies a position of the LSC within the sub-block that includes the LSC.

主权项

1. A method of decoding a block of transform coefficients associated with a block of video data during a video decoding process, wherein the block of transform coefficients includes a plurality of sub-blocks, the method comprising:
decoding information that identifies a position within the block of transform coefficients of one of the coefficients that is a last significant coefficient (LSC) for the block according to a scanning order associated with the block of transform coefficients, wherein the scanning order associated with the block of transform coefficients comprises a scanning order of the sub-blocks within the block of transform coefficients and a scanning order of coefficients within the sub-blocks, and wherein decoding the information that identifies the position within the block of transform coefficients of the one of the coefficients that is the LSC for the block comprises:
decoding an LSC sub-block position that identifies a position of one of the sub-blocks that includes the LSC within the block, anddecoding an LSC coefficient position that identifies a position of the LSC within the sub-block that includes the LSC, the method further comprising:
for each of one or more other sub-blocks of the plurality of sub-blocks, decoding a coefficient position identifying a position of a last significant coefficient within the sub-block according to the scanning order of coefficients within the sub-blocks, anddecoding the block of transform coefficients based on:
the position of the LSC for the block identified by the LSC sub-block position and the LSC coefficient position, andthe position of the last significant coefficient within each of the one or more other sub-blocks of the block.