Context modeling for transform coefficient coding
A device for coding video data is configured to determine a context for a first syntax element based on already coded information for a current block of video data, wherein a value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the current block of video data; and code the first syntax element based on the determined context.
1. A method for coding video data, the method comprising;
determining a context for a first syntax element for a current block of video data based on a coding mode of the current block, wherein the coding mode comprises one of an intra coding mode or an inter coding mode, wherein a value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the current block of video data;
determining a probability model based on the determined context for the first syntax element; and
context coding the first syntax element based on the determined probability model.
2. The method of claim 1 , wherein the current block comprises a luma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the luma block.
3. The method of claim 1 , wherein the current block comprises a chroma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the chroma block.
4. The method of claim 1 , wherein the current block comprises a chroma block and a luma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with at least one of the chroma block or the luma block.
5. The method of claim 1 , wherein the current block of video data comprises a first block, the method further comprising:
determining a context for a merge flag for a second block based on the value of the first syntax element, wherein the second block is a neighboring block of the first block and is coded after the first block.
6. The method of claim 1 , wherein context coding the first syntax element based on the determined probability model comprises performing a context-adaptive binary arithmetic coding (CABAC) operation on the first syntax element.
7. The method of claim 1 , wherein coding comprises encoding, and wherein context coding the first syntax element based on the determined probability model comprises outputting a bitstream of encoded video data comprising the first syntax element.
8. The method of claim 1 , wherein coding comprises decoding, and wherein context coding the first syntax element based on the determined probability model comprises receiving a bitstream of encoded video data comprising the first syntax element and determining the value for the first syntax element.
9. A device for coding video data, the device comprising:
a memory; and
one or more processors configured to:
determine a context for a first syntax element for a current block of video data based on a coding mode of the current block, wherein the coding mode comprises one of an intra coding mode or an inter coding mode, wherein a value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the current block of video data;
determine a probability model based on the determined context for the first syntax element;
context code the first syntax element based on the determined probability model.
10. The device of claim 9 , wherein the current block comprises a luma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the luma block.
11. The device of claim 9 , wherein the current block comprises a chroma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with the chroma block.
12. The device of claim 9 , wherein the current block comprises a chroma block and a luma block, and wherein the value for the first syntax element indicates whether there is at least one non-zero transform coefficient level associated with at least one of the chroma block or the luma block.
13. The device of claim 9 , wherein the current block of video data comprises a first block, and wherein the one or more processors are further configured to:
determine a context for a merge flag for a second block based on the value of the first syntax element, wherein the second block is a neighboring block of the first block and is coded after the first block.
14. The device of claim 9 , wherein to context code the first syntax element based on the determined probability model, the one or more processors are configured to perform a context-adaptive binary arithmetic coding (CABAC) operation on the first syntax element.
15. The device of claim 9 , wherein the device comprises a video encoder, and wherein to context code the first syntax element based on the determined probability model, the one or more processors are further configured to output a bitstream of encoded video data comprising the first syntax element.
16. The device of claim 9 , wherein device comprises a video decoder, and wherein to context code the first syntax element based on the determined probability model, the one or more processors are further configured to receive a bitstream of encoded video data comprising the first syntax element and determining the value for the first syntax element.