Video coding / decoding with sub-block transform sizes and adaptive deblock filtering

A computer system comprising one or more processing units and memory, wherein the computer system implements a video decoder system comprising:

• an input buffer configured to store encoded video data, in a bitstream, for a current frame of a video sequence;
• a frame buffer configured to store a reference frame for use in motion compensation;
• and
• a video decoder, implemented with the one or more processing units and memory, configured to:
• reconstruct the current frame;
• adaptively filter one or more boundaries between multiple blocks in the reconstructed current frame to reduce boundary discontinuities, wherein application of the filtering across a given boundary of the one or more boundaries includes:
• computing a cross boundary discontinuity measure that quantifies pixel value discontinuity across the given boundary, wherein the cross boundary discontinuity measure is computed using at least one pixel value on a first side of the given boundary and at least one pixel value on a second side of the given boundary, the first side of the given boundary being opposite the second side of the given boundary;
• computing a first side discontinuity measure that quantifies pixel value discontinuity on the first side of the given boundary, wherein the first side discontinuity measure is computed using multiple pixel values on the first side of the given boundary;
• computing a second side discontinuity measure that quantifies pixel value discontinuity on the second side of the given boundary, wherein the second side discontinuity measure is computed using multiple pixel values on the second side of the given boundary;
• and
• determining whether to filter the given boundary and, if so, filtering the given boundary, including adjusting the filtering the given boundary depending at least in part on the cross boundary discontinuity measure, the first side discontinuity measure, and the second side discontinuity measure;
• and
• store the adaptively filtered, reconstructed current frame in the frame buffer.

One or more computer-readable memory or storage devices having stored thereon encoded data formatted for decoding with operations that include:

• reconstructing a frame of a video sequence;
• adaptively filtering one or more boundaries between multiple blocks in the reconstructed frame to reduce boundary discontinuities, wherein application of the filtering across a given boundary of the one or more boundaries includes:
• computing a cross boundary discontinuity measure that quantifies pixel value discontinuity across the given boundary, wherein the cross boundary discontinuity measure is computed using at least one pixel value on a first side of the given boundary and at least one pixel value on a second side of the given boundary, the first side of the given boundary being opposite the second side of the given boundary;
• computing a first side discontinuity measure that quantifies pixel value discontinuity on the first side of the given boundary, wherein the first side discontinuity measure is computed using multiple pixel values on the first side of the given boundary;
• computing a second side discontinuity measure that quantifies pixel value discontinuity on the second side of the given boundary, wherein the second side discontinuity measure is computed using multiple pixel values on the second side of the given boundary;
• and
• determining whether to filter the given boundary and, if so, filtering the given boundary, including adjusting the filtering the given boundary depending at least in part on the cross boundary discontinuity measure, the first side discontinuity measure, and the second side discontinuity measure;
• and
• storing the adaptively filtered, reconstructed frame in a frame buffer for use as a reference frame in subsequent motion compensation.