Transmission and decoding of picture signals.

摘要

A picture series is encoded so that a first type of decoder having only one frame memory and incapable of bidirectional decoding can decode an encoded bitstream, and a second type of decoder having multiple frame memories and capable of bi-directional decoding can decode an encoded bitstream to produce a higher quality decoded picture series. The encoded bitstream comprises three parallel channels (channels 0 to 1) of encoded picture data. The first channel (channel 0) includes every other picture and header information common to the second and third channels. The second channel (channel 1) includes the pictures not represented in the first channel and encoded by one of forward and backward predictive coding. The third channel (channel 3) includes the pictures not represented in the first channel and encoded by bi-directional predictive coding. The first type of decoder uses the first and second channels, while the second type of decoder uses the first and third channels.