Seamless Splicing for MPEG-2 Transport Stream Video Servers

Current uncompressed video servers are capable of streaming multiple video clips back to back such that they appear to be a single uninterrupted stream. This is a relatively simple process made possible in part by the fact that frame boundaries are equally spaced and there are no inter- frame dependencies. With the adoption of MPEG-2 and DV digital television standards, the distribution of video in compressed format will become more common. This change is fueling the development of video servers capable of distributing compressed video in broadcast ready format. The seamless concatenation and splicing of streams that has been taken for granted in the uncompressed domain becomes complex in the compressed domain due to mechanics of MPEG-2 encoding. This paper describes the problems associated with concatenating MPEG-2 Transport Streams (TS) and describes a technique to perform frame accurate seamless splicing from one MPEG-2 TS to another on compressed stream video servers such as the Silicon Graphics Incorporated Origin 2000. Using this technique, a transition clip is constructed to replace a short segment of each MPEG-2 TS near the splice point. Shortly before the splice point, the server begins streaming the transition clip which contains the actual splice. At the end of the transition clip, the playout engine switches to the second TS. The transition clip must be constructed such that when concatenated with each TS, the resulting stream is still valid. This approach offers several benefits for use with video servers: neither of the original transport streams is modified; transitions for pre-scheduled splices can be calculated in advance; transitions can be generated once and later reused without additional overhead.

Published

1999-02

Content type

Original Research

DOI

10.5594/M00953

ISBN

978-1-61482-930-0