Adaptive GOP structure in video streaming

摘要

This system adaptively assigns picture types used for temporal compression to frames of streaming video at the input. Based on threshold testing of two metrics that are measures of distance between the frames at the input, a frame may be assigned to be compressed as an I, P, or B frame or be skipped over by the system without being coded at all.

主权项

1. A method of encoding video frames comprising:
determining at least one metric indicative of a difference between a selected video frame and at least one adjacent video frame, wherein the metric is determined according toM=γCγP+λ⁡(2⁢⁢λ+1),(3)where γC is a ratio of luminance value differences between the selected video frame and each of a preceding adjacent video frame and a following adjacent video frame, γP is a preceding ratio of luminance value differences for the preceding adjacent video frame, and λ is a luminance histogram difference between the selected video frame and the preceding adjacent video frame; and
adaptively assigning an encoding method to the selected video frame based on the determined metric, comprising:
encoding the selected video frame as an intra-predictively coded (I) frame type when the determined metric is larger than a first threshold value indicative of a scene change;encoding the selected video frame as an unidirectional inter-predictively coded (P) frame type when the determined metric is larger than a second threshold value and less than the first threshold value, wherein the second threshold value is less than the first threshold value; andencoding the selected video frame as a bidirectional inter-predictively coded (B) frame type when the determined metric is larger than a third threshold value and less than the second threshold value, wherein the third threshold value is less than the second threshold value.