Post-processing of MPEG2 coded video for transmission at lower bit rates

It is expected that most of the video services will be based on the MPEG2 standard and many of them using recorded streams. When compressed video is recorded, the characteristics of the channel through which it will be transmitted are assumed to be known beforehand. Therefore a great lack of flexibility arises in transmission of these streams when channels of diverse characteristics are used. If the same video programme is to be simultaneously distributed to several users through channels with different capacities, the service provider needs to keep several copies of that programme, each one encoded according to the corresponding channel characteristics. We show that it is only required to keep one copy of the coded data at its highest possible quality. Transcoding the main stream to lower rates is achieved with minimum delay. Therefore the transcoder is also capable of fast response to network demands to prevent packet loss.