Flexible switching and editing of MPEG-2 video bitstreams

This paper proposes and compares solutions for switching and editing of compressed video signals in the programme chain. Proposals for bitstream splicing have been made, but these lack flexibility. Also, switching in the decoded domain degrades picture quality. The ACTS ATLANTIC project has developed an alternative approach, in which the decoded signals are switched, but recording makes intelligent use of the coding decisions used to create the original bitstreams. This paper outlines the techniques used in this approach, and gives results of simulations. Examples of implementations for "opt-out" and editing applications are given. The paper proposes techniques which allows the frame-accurate switching and editing of MPEG-2 bitstreams without introducing any visible impairment. The techniques are also applicable to other types of compression.