Representative motion information for temporal motion prediction in video encoding and decoding

One or more non-transitory computer-readable media having stored thereon computer-executable instructions for causing one or more processing units, when programmed thereby, to perform operations of a video decoder, the operations comprising:

• receiving encoded data in a bitstream for at least part of a video sequence;
• decoding a first frame of the video sequence using a first portion of the encoded data;
• buffering, in memory, the first frame for use as a reference frame;
• buffering, in memory, representative motion vector information and representative reference frame index information for the reference frame, including buffering representative motion vector information and representative reference frame index information for a group of blocks in the reference frame, wherein the representative reference frame index information for the group of blocks is reference frame index information of a representative block of the group of blocks, and wherein the representative motion vector information for the group of blocks is a motion vector of the representative block of the group of blocks;
• and
• decoding a second frame of the video sequence using a second portion of the encoded data, including using the motion vector and the reference frame index information of the representative block of the group of blocks to reconstruct a block of the second frame.

One or more non-transitory computer-readable media having stored thereon encoded data in a bitstream for at least part of a video sequence, the encoded data having been encoded, with a computer system that implements a video encoder, by operations comprising:

• encoding a first frame of a video sequence, thereby producing a first portion of encoded data;
• reconstructing the first frame;
• buffering, in memory, the first frame for use as a reference frame;
• buffering, in memory, representative motion vector information and representative reference frame index information for the reference frame, including buffering representative motion vector information and representative reference frame index information for a group of blocks in the reference frame, wherein the representative reference frame index information for the group of blocks is reference frame index information of a representative block of the group of blocks, and wherein the representative motion vector information for the group of blocks is a motion vector of the representative block of the group of blocks;
• and
• encoding a second frame of the video sequence, thereby producing a second portion of the encoded data, including using the motion vector and the reference frame index information of the representative block of the group of blocks to encode a block of the second frame.