Size based transform unit context derivation

1. An apparatus, comprising:

memory;

instructions; and

circuitry to execute the instructions to cause the circuitry to at least:

determine a transform unit (TU) size for a node of a TU quadtree, the TU associated with a coding unit (CU) and the TU associated with a video frame,

determine a context index value associated with an individual node of the TU quadtree based at least in part on the TU size, wherein to determine the context index value, the circuitry is to determine a difference between a binary logarithm of a maximum TU size and a binary logarithm of the transform unit size, and

determine a transform split flag based at least in part on the determined context index value.

2. The apparatus of claim 1 , wherein the circuitry is to determine the context index value as part of a context adaptive entropy coding operation to determine one or more transform split flags.

3. The apparatus of claim 1 , wherein the circuitry is to determine the context index value as part of an entropy Context-adaptive binary arithmetic coding (CABAC) coding of transform split flags to determine one or more transform split flags.

4. The apparatus of claim 1 , wherein the circuitry is to:

determine a first split flag having a first value when the transform unit has a size in excess of a first size, and wherein the first split flag is not explicitly provided in a bitstream; and

determine a second split flag of second value when the transform unit has a second size, and wherein the second split flag is not explicitly provided in a bitstream.

5. The apparatus of claim 1 , further comprising a video encoder, wherein the circuitry is part of the video encoder.

6. A system comprising:

a display;

an antenna configured to receive an encoded bitstream of video data;

a memory to store the bitstream;

a processor communicatively coupled to the display, antenna, and memory; and

decoder circuitry to:

determine a transform unit (TU) size for a node of a TU quadtree, the TU associated with a coding unit (CU) and the TU associated with a video frame,

determine a context index value associated with an individual node of the TU quadtree based at least in part on the TU size, wherein to determine the context index value, the circuitry is to determine a difference between a binary logarithm of a maximum TU size and a binary logarithm of the transform unit size, and

determine a transform split flag based at least in part on the determined context index value.

7. The system of claim 6 , wherein the decoder circuitry is to determine the context index value as part of a context adaptive entropy coding operation to determine one or more transform split flags.

8. The system of claim 6 , wherein the decoder circuitry is to determine the context index value as part of an entropy Context-adaptive binary arithmetic coding (CABAC) coding of transform split flags to determine one or more transform split flags.

9. The system of claim 6 , wherein the decoder circuitry is to:

determine a first split flag having a first value when the transform unit has a first size, and wherein the first split flag is not explicitly provided in the bitstream; and

determine a second split flag of second value when the transform unit has a second size, and wherein the second split flag is not explicitly provided in the bitstream.

10. The system of claim 9 , wherein the first size is 64×64 and the second size 4×4.

11. At least one non-transitory article comprising a computer program stored thereon having instructions that, if executed by the computer, cause the computer to:

determine a transform unit (TU) size for a node of a TU quadtree, the TU associated with a coding unit (CU) and the TU associated with a video frame,

determine a context index value associated with an individual node of the TU quadtree based at least in part on the TU size, wherein to determine the context index value;

determine a difference between a binary logarithm of a maximum TU size and a binary logarithm of the transform unit size, and

determine a transform split flag based at least in part on the determined context index value.

12. The non-transitory article of claim 11 , wherein the instructions, when executed, cause the computer to determine the context index value as part of a context adaptive entropy coding operation to determine one or more transform split flags.

13. The non-transitory article of claim 11 , wherein the instructions, when executed, cause the computer to determine the context index value as part of an entropy Context-adaptive binary arithmetic coding (CABAC) coding of transform split flags to determine one or more transform split flags.

14. The non-transitory article of claim 11 , wherein the instructions, when executed, cause the computer:

determine a first split flag having a first value when the transform unit has a first size, and wherein the first split flag is not explicitly provided in a bitstream; and

determine a second split flag of second value when the transform unit has a second size, and wherein the second split flag is not explicitly provided in the bitstream.

15. The non-transitory article of claim 14 , wherein the first size is 64×64 and the second size 4×4.