Video coding using mapped transforms and scanning modes

A device configured to decode video data, the device comprising:

• a memory configured to store encoded video data;
• and
• one or more processors in communication with the memory, the one or more processors configured to:
• receive the encoded video data encoded according to an intra-prediction mode;
• entropy decode the encoded video data to create a one-dimensional array of transform coefficients;
• determine a subset of transform and scanning mode combinations based on the intra-prediction mode of the encoded video data, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• determine a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size signaled in the encoded video bitstream;
• scan the one-dimensional array of transform coefficients with the determined scanning mode of the determined transform and scanning mode combination to produce a two-dimensional array of transform coefficients;
• and
• inverse transform the two-dimensional array of transform coefficients with the determined transform of the determined transform and scanning mode combination to produce a block of residual video data.

A device configured to decode video data, the device comprising:

• means for receiving encoded video data encoded according to an intra-prediction mode;
• means for entropy decoding the encoded video data to create a one-dimensional array of transform coefficients;
• means for determining a subset of transform and scanning mode combinations based on the intra-prediction mode of the encoded video data, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• means for determining a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size signaled in the encoded video bitstream;
• means for scanning the one-dimensional array of transform coefficients with the determined scanning mode of the determined transform and scanning mode combination to produce a two-dimensional array of transform coefficients;
• and
• means for inverse transforming the two-dimensional array of transform coefficients with the determined transform of the determined transform and scanning mode combination to produce a block of residual video data.

A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors of a device configured to decode video data to:

• receive the encoded video data encoded according to an intra-prediction mode;
• entropy decode the encoded video data to create a one-dimensional array of transform coefficients;
• determine a subset of transform and scanning mode combinations based on the intra-prediction mode of the encoded video data, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• determine a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size signaled in the encoded video bitstream;
• scan the one-dimensional array of transform coefficients with the determined scanning mode of the determined transform and scanning mode combination to produce a two-dimensional array of transform coefficients;
• and
• inverse transform the two-dimensional array of transform coefficients with the determined transform of the determined transform and scanning mode combination to produce a block of residual video data.

A method of encoding video data, the method comprising:

• encoding video data according to an intra-prediction mode to create a block of residual data;
• determining a subset of transform and scanning mode combinations based on the intra- prediction mode, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• determining a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size;
• transforming the block of residual data with a transform of the determined transform and scanning mode combination to produce a first transform coefficients array having the transform block size;
• scanning the first transform coefficients array with a scanning mode of the determined transform and scanning mode combination to produce a second transform coefficients array;
• and
• entropy encoding the second transform coefficients array.

A device configured to encode video data, the device comprising:

• a memory configured to store video data;
• and
• one or more processors in communication with the memory, the one or more processors configured to:
• encode the video data according to an intra-prediction mode to create a block of residual data;
• determine a subset of transform and scanning mode combinations based on the intra-prediction mode, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• determine a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size;
• transform the block of residual data with a transform of the determined transform and scanning mode combination to produce a first transform coefficients array having the transform block size;
• scan the first transform coefficients array with a scanning mode of the determined transform and scanning mode combination to produce a second transform coefficients array;
• and
• entropy encode the second transform coefficients array.

A device configured to encode video data, the device comprising:

• means for encoding video data according to an intra-prediction mode to create a block of residual data;
• means for determining a subset of transform and scanning mode combinations based on the intra-prediction mode, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• means for determining a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size;
• means for transforming the block of residual data with a transform of the determined transform and scanning mode combination to produce a first transform coefficients array having the transform block size;
• means for scanning the first transform coefficients array with a scanning mode of the determined transform and scanning mode combination to produce a second transform coefficients array;
• and
• means for entropy encoding the second transform coefficients array.

A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors of a device configured to encode video data to:

• encode video data according to an intra-prediction mode to create a block of residual data;
• determine a subset of transform and scanning mode combinations based on the intra- prediction mode, the subset of transform and scanning mode combinations consisting of one or more scanning modes having predefined scanning orders;
• determine a transform and scanning mode combination from the subset of transform and scanning mode combinations based on a transform block size;
• transform the block of residual data with a transform of the determined transform and scanning mode combination to produce a first transform coefficients array having the transform block size;
• scan the first transform coefficients array with a scanning mode of the determined transform and scanning mode combination to produce a second transform coefficients array;
• and
• entropy encode the second transform coefficients array.