Entropy coding using pre-defined, fixed CDFS

1 . A method, comprising:

determining a predictor value corresponding to a transform coefficient of a sequence of transform coefficients, the predictor value being generated by a predictor function that adapts to changes in a statistical distribution of the sequence of transform coefficients over time;

selecting, based on the predictor value, a probability model from a set of pre-defined probability models; and

entropy coding a symbol associated with the transform coefficient using the probability model.

2 . The method of claim 1 , wherein selecting the probability model comprises:

obtaining an index based on the predictor value; and

using the index into a table of the pre-defined probability models.

3 . The method of claim 2 , wherein obtaining the index based on the predictor value comprises:

quantizing or scaling the predictor value to obtain the index.

4 . The method of claim 1 , wherein the symbol associated with the transform coefficient represents a base level of the transform coefficient.

5 . The method of claim 1 , wherein determining the predictor value corresponding to the transform coefficient of the sequence of the transform coefficients comprises:

calculating the predictor value based on a previous predictor value used for coding an immediately preceding symbol associated with an immediately preceding transform coefficient of the sequence of the transform coefficients.

6 . The method of claim 5 , wherein the predictor value is calculated further based on the immediately preceding symbol.

7 . The method of claim 1 , wherein selecting the probability model based on the predictor value comprises:

selecting the probability model based on a location of the transform coefficient in a transform block.

8 . A device, comprising:

a processor configured to execute instructions to:

determine a predictor value corresponding to a transform coefficient of a sequence of transform coefficients, the predictor value being generated by a predictor function that adapts to changes in a statistical distribution of the sequence of transform coefficients over time;

select, based on the predictor value, a probability model from a set of pre-defined probability models; and

entropy code a symbol associated with the transform coefficient using the probability model.

9 . The device of claim 8 , wherein to select the probability model comprises to:

obtain an index based on the predictor value; and

use the index into a table of the pre-defined probability models.

10 . The device of claim 9 , wherein to obtain the index based on the predictor value comprises to:

quantize or scale the predictor value to obtain the index.

11 . The device of claim 8 , wherein the symbol associated with the transform coefficient represents a base level of the transform coefficient.

12 . The device of claim 8 , wherein to determine the predictor value corresponding to the transform coefficient of the sequence of the transform coefficients comprises to:

calculate the predictor value based on a previous predictor value used for coding an immediately preceding symbol associated with an immediately preceding transform coefficient of the sequence of the transform coefficients.

13 . The device of claim 12 , wherein the predictor value is calculated further based on the immediately preceding symbol.

14 . The device of claim 8 , wherein to select the probability model based on the predictor value comprises to:

select the probability model based on a location of the transform coefficient in a transform block.

15 . A non-transitory computer-readable storage medium, comprising executable instructions that, when executed by a processor, facilitate performance of operations, comprising:

determining a predictor value corresponding to a transform coefficient of a sequence of transform coefficients, the predictor value being generated by a predictor function that adapts to changes in a statistical distribution of the sequence of transform coefficients over time;

selecting, based on the predictor value, a probability model from a set of pre-defined probability models; and

entropy coding a symbol associated with the transform coefficient using the probability model.

16 . The non-transitory computer-readable storage medium of claim 15 , wherein selecting the probability model comprises:

obtaining an index based on the predictor value; and

using the index into a table of the pre-defined probability models.

17 . The non-transitory computer-readable storage medium of claim 16 , wherein obtaining the index based on the predictor value comprises:

quantizing or scaling the predictor value to obtain the index.

18 . The non-transitory computer-readable storage medium of claim 15 , wherein the symbol associated with the transform coefficient represents a base level of the transform coefficient.

19 . The non-transitory computer-readable storage medium of claim 15 , wherein determining the predictor value corresponding to the transform coefficient of the sequence of the transform coefficients comprises:

calculating the predictor value based on a previous predictor value used for coding an immediately preceding symbol associated with an immediately preceding transform coefficient of the sequence of the transform coefficients.

20 . The non-transitory computer-readable storage medium of claim 15 , wherein selecting the probability model based on the predictor value comprises:

selecting the probability model based on a location of the transform coefficient in a transform block.