Coding the position of a last significant coefficient within a video block based on a scanning order for the block in video coding

An apparatus for coding coefficients associated with a block of video data during a video coding process, the apparatus comprising a video coder configured to:

• determine contexts for performing context adaptive entropy coding of the x- and y-coordinates indicating a horizontal position and a vertical position, respectively, of a last non-zero coefficient within the block, wherein the contexts indicate a probability of each of x- and y-coordinates comprising a given value when the coefficients of the block of video data are scanned in a first scanning order;
• when the coefficients of the block of video data are scanned in the first scanning order, code the x-coordinate and the y-coordinate using the determined contexts such that the x-coordinate is coded based on the probability of the x-coordinate comprising a given value and the y-coordinate is coded based on the probability of the y-coordinate comprising a given value;
• and
• interchange the x- and y-coordinates when the coefficients of the block of video data are scanned in the second scanning order and code the interchanged x-coordinate and the interchanged y-coordinate using the determined contexts such that the interchanged x-coordinate is coded based on the probability of the y-coordinate comprising a given value and the interchanged y-coordinate is coded based on the probability of the x-coordinate comprising a given value.

A device for coding coefficients associated with a block of video data during a video coding process, the device comprising:

• means for determining contexts for performing context adaptive entropy coding of the x-and y-coordinates indicating a horizontal position and a vertical position, respectively, of a last non-zero coefficient within the block, wherein the contexts indicate a probability of each of x-and y-coordinates comprising a given value when the coefficients of the block of video data are scanned in a first scanning order;
• when the coefficients of the block of video data are scanned in the first scanning order, means for coding the x-coordinate and the y-coordinate using the determined contexts such that the x-coordinate is coded based on the probability of the x-coordinate comprising a given value and the y-coordinate is coded based on the probability of the y-coordinate comprising a given value;
• and
• means for interchanging the x- and y-coordinates when the coefficients of the block of video data are scanned in the second scanning order and coding the interchanged x-coordinate and the interchanged y-coordinate using the determined contexts such that the interchanged x-coordinate is coded based on the probability of the y-coordinate comprising a given value and the interchanged y-coordinate is coded based on the probability of the x-coordinate comprising a given value.

A non-transitory computer-readable medium comprising instructions that, when executed, cause a processor to code coefficients associated with a block of video data during a video coding process, wherein the instructions cause the processor to:

• determine contexts for performing context adaptive entropy coding of the x- and y-coordinates indicating a horizontal position and a vertical position, respectively, of a last non-zero coefficient within the block, wherein the contexts indicate a probability of each of x- and y-coordinates comprising a given value when the coefficients of the block of video data are scanned in a first scanning order;
• when the coefficients of the block of video data are scanned in the first scanning order, code the x-coordinate and the y-coordinate using the determined contexts such that the x-coordinate is coded based on the probability of the x-coordinate comprising a given value and the y-coordinate is coded based on the probability of the y-coordinate comprising a given value;
• and
• interchange the x- and y-coordinates when the coefficients of the block of video data are scanned in the second scanning order and code the interchanged x-coordinate and the interchanged y-coordinate using the determined contexts such that the interchanged x-coordinate is coded based on the probability of the y-coordinate comprising a given value and the interchanged y-coordinate is coded based on the probability of the x-coordinate comprising a given value.