Signaling of quantization information in non-quadtree-only partitioned video coding

A method of encoding video data, the method comprising:

• determining, by a video encoder, a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• quantizing, by the video encoder, based on a quantization parameter, at least one transform coefficient of a current coding unit (CU), the current CU being in a current quantization group or corresponding to a coding block in the current quantization group, wherein the current quantization group is defined as a group of successive, in coding order, CUs in the plurality of CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• signaling, by the video encoder, in a bitstream that comprises an encoded representation of the video data, local quantization information for the current quantization group, wherein the quantization parameter is derivable based at least in part on the local quantization information for the current quantization group;
• and
• including, by the video encoder, in the bitstream, one or more syntax elements representing the quantized transform coefficient of the current CU.

An apparatus for decoding video data comprising:

• one or more storage media configured to store the video data;
• and
• one or more processors configured to:
• receive in a bitstream that comprises an encoded representation of the video data, local quantization information for a current quantization group;
• determine a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• derive, based at least in part on the local quantization information for the current quantization group, a quantization parameter, wherein the current quantization group is defined as a group of successive, in coding order, CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• inverse quantize, based on the quantization parameter, at least one transform coefficient of a current CU, the current CU being one of the CUs in the current quantization group;
• and
• reconstruct, based on inverse quantized transform coefficients of the current CU, a coding block of the current CU.

An apparatus for encoding video data, the apparatus comprising:

• one or more storage media configured to store the video data;
• and
• one or more processors configured to:
• determine a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• quantize, based on a quantization parameter, at least one transform coefficient of a current coding unit (CU), the current CU being in a current quantization group or corresponding to a coding block in the current quantization group, wherein the current quantization group is defined as a group of successive, in coding order, CUs in the plurality of CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• signal, in a bitstream that comprises an encoded representation of the video data, local quantization information for the current quantization group, wherein the quantization parameter is derivable based at least in part on the local quantization information for the current quantization group;
• and
• include, in the bitstream, one or more syntax elements representing the quantized transform coefficient of the current CU.

An apparatus for decoding video data, the apparatus comprising:

• means for receiving, in a bitstream that comprises an encoded representation of the video data, local quantization information for a current quantization group;
• means for determining a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• means for deriving, based at least in part on the local quantization information for the current quantization group, a quantization parameter, wherein the current quantization group is defined as a group of successive, in coding order, CUs or coding blocks so that boundaries of the current quantization group must be boundaries of the CUs in the plurality of CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• means for inverse quantizing, based on the quantization parameter, at least one transform coefficient of a current CU, the current CU being one of the CUs in the current quantization group;
• and
• means for reconstructing, based on inverse quantized transform coefficients of the current CU, a coding block of the current CU.

An apparatus for encoding video data, the apparatus comprising:

• means for determining a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• means for quantizing, based on a quantization parameter, at least one transform coefficient of a current coding unit (CU), the current CU being in a current quantization group or corresponding to a coding block in the current quantization group, wherein the current quantization group is defined as a group of successive, in coding order, CUs in the plurality of CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• means for signaling, in a bitstream that comprises an encoded representation of the video data, local quantization information for the current quantization group, wherein the quantization parameter is derivable based at least in part on the local quantization information for the current quantization group;
• and
• means for including, in the bitstream, one or more syntax elements representing the quantized transform coefficient of the current CU.

A computer-readable storage medium storing instructions that, when executed, cause one or more processors to:

• receive, in a bitstream that comprises an encoded representation of the video data, local quantization information for a current quantization group;
• determine a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• derive, based at least in part on the local quantization information for the current quantization group, a quantization parameter, wherein the current quantization group is defined as a group of successive, in coding order, CUs in the plurality of CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• inverse quantize, based on the quantization parameter, at least one transform coefficient of a current CU, the current CU being one of the CUs in the current quantization group;
• and
• reconstruct, based on inverse quantized transform coefficients of the current CU, a coding block of the current CU.

A computer-readable storage medium storing instructions that, when executed, cause one or more processors to:

• determine, a partitioning of a coding tree unit (CTU) of a picture of the video data into a plurality of coding units (CUs), the plurality of CUs including one or more non-square CUs;
• quantize, based on a quantization parameter, at least one transform coefficient of a current coding unit (CU), the current CU being in a current quantization group or corresponding to a coding block in the current quantization group, wherein the current quantization group is defined as a group of successive, in coding order, CUs in the plurality of CUs so that boundaries of the current quantization group must be boundaries of the CUs and a size of the current quantization group is greater than or equal to a threshold, and at least one CU of the plurality of CUs is included in a non-square quantization group;
• signal, in a bitstream that comprises an encoded representation of the video data, local quantization information for the current quantization group, wherein the quantization parameter is derivable based at least in part on the local quantization information for the current quantization group;
• and
• include, in the bitstream, one or more syntax elements representing the quantized transform coefficient of the current CU.