Coefficient scanning in video coding

An apparatus for decoding transform coefficients in a video decoding process, the apparatus comprising:

• a memory configured to store a one-dimensional array of transform coefficients associated with a block of transform coefficients;
• and
• one or more processors configured to:
• obtain, from an encoded bitstream, the one-dimensional array of transform coefficients;
• determine a plurality of sub-blocks of transform coefficients for the block of transform coefficients, each sub-block of the plurality of sub-blocks having an equal size;
• decode, from an encoded bitstream, data that represents a unified scan order for scanning a set of information of the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• determine, based on the data that represents the unified scan order for the set of information, a unified diagonal scan for scanning the significance information of the transform coefficients of respective sub-blocks, the coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• scan on the one-dimensional array of transform coefficients according to the unified diagonal scan, the scan comprising scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and scanning the plurality of sub-blocks using the unified diagonal scan to produce the block of transform coefficients;
• and
• decode the block of transform coefficients.

An apparatus for decoding transform coefficients in a video decoding process, the apparatus comprising:

• means for obtaining, from an encoded bitstream, a one-dimensional array of transform coefficients associated with a block of transform coefficients;
• means for determining a plurality of sub-blocks of transform coefficients for the block of transform coefficients, each sub-block of the plurality of sub-blocks having an equal size;
• means for decoding, from an encoded bitstream, data that represents a unified scan order for scanning a set of information of the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks:
• means for determining, based on the data that represents the unified scan order for the set of information, a unified diagonal scan for scanning the significance information of the transform coefficients of respective sub-blocks, the coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• means for scanning the one-dimensional array of transform coefficients according to the unified diagonal scan, wherein the means for scanning comprises means for scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and means for scanning the plurality of sub-blocks using the unified diagonal scan to produce the block of transform coefficients;
• and
• means for decoding the block of transform coefficients.

A non-transitory computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to:

• obtain, from an encoded bitstream, a one-dimensional array of transform coefficients associated with a block of transform coefficients;
• determine a plurality of sub-blocks of transform coefficients for the block of transform coefficients, each sub-block of the plurality of sub-blocks having an equal size;
• decode, from an encoded bitstream, data that represents a unified scan order for scanning a set of information of the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks
• determine, based on the data that represents the unified scan order for the set of information, a unified diagonal scan for scanning the significance information of the transform coefficients of respective sub-blocks, the coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• scan on the one-dimensional array of transform coefficients according to the unified diagonal scan, the scan comprising scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and scanning the plurality of sub-blocks using the unified diagonal scan to produce the block of transform coefficients;
• and
• decode the block of transform coefficients.

A method for encoding transform coefficients in a video encoding process comprising:

• dividing a block of transform coefficients into a plurality of sub-blocks, each sub-block of the plurality of sub-blocks having an equal size;
• determining, for the block of transform coefficients, a unified diagonal scan for scanning a set of information for the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• scanning the block of transform coefficients according to the unified diagonal scan, wherein the scanning comprises scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and scanning the plurality of sub-blocks using the unified diagonal scan to produce a one-dimensional array of transform coefficients;
• and
• encoding the transform coefficients and the data that represents the unified diagonal scan order.

An apparatus for encoding transform coefficients in an encoding process, the apparatus comprising:

• a memory configured to store a block of transform coefficients;
• and
• one or more processors configured to:
• divide the block of transform coefficients into a plurality of sub-blocks, each sub-block of the plurality of sub-blocks having an equal size;
• determine, for the block of transform coefficients, a unified diagonal scan for scanning a set of information for the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• scan the block of transform coefficients according to the unified diagonal scan, wherein to scan the block the one or more processors are configured to scan the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and scan the plurality of sub-blocks using the unified diagonal scan to produce a one-dimensional array of transform coefficients;
• and
• encode the transform coefficients and the data that represents the unified diagonal scan order.

An apparatus for encoding transform coefficients in a video encoding process, the apparatus comprising:

• means for dividing a block of transform coefficients into a plurality of sub-blocks, each sub-block of the plurality of sub-blocks having an equal size;
• means for determining, for the block of transform coefficients, a unified diagonal scan for scanning a set of information for the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• means for scanning on the block of transform coefficients according to the unified diagonal scan, wherein the means for scanning comprises means for scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and means for scanning the plurality of sub-blocks using the unified diagonal scan;
• and
• means for encoding the transform coefficients and the data that represents the unified diagonal scan order.

A non-transitory computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to:

• divide a block of transform coefficients into a plurality of sub-blocks, each sub-block of the plurality of sub-blocks having an equal size;
• determine, for the block of transform coefficients, a unified diagonal scan for scanning a set of information for the block, wherein the set of information comprises significance information of the transform coefficients of respective sub-blocks, coefficient level information of the transform coefficients of respective sub-blocks, and the plurality of sub-blocks;
• scan perform a scan on the block of transform coefficients according to the unified diagonal scan, the scanning comprising scanning the significance information of the transform coefficients and the coefficient level information of the transform coefficients for each sub-block of the plurality of sub-blocks using the unified diagonal scan and scanning the plurality of sub-blocks using the unified diagonal scan to produce a one-dimensional array of transform coefficients;
• and
• encode the transform coefficients and the data that represents the unified diagonal scan order.