Creating and sharing knowledge for telecommunications

Rate reduction techniques for MPEG-2 video bit streams

Assunção, P.A. ; Ghanbari, M.

Rate reduction techniques for MPEG-2 video bit streams, Proc Digital Compression Technologies & Systems for Video Communications, Berlin, Germany, Vol. 2952, pp. 450 - 459, September, 1996.

Digital Object Identifier: doi:10.1117/12.251306

Abstract
Rate control is usually an intrinsic function of the video coding algorithm, responsible for matching the available bandwidth of the communication channel to the output bit stream. However, many of the forthcoming video services will use pre-encoded video, in compressed format, for storage and transmission purposes. In this case, the rate control function should work on the compressed bit stream by reducing its bit rate according to the network demand, which can be either static or dynamic. Bit rate reduction of compressed video is needed not only when pre-encoded video is transmitted, but also in video multicasting where several users receive the same bit stream through different channels. A similar problem results from the interactivity with the user in video on demand services, where each user is offered the possibility of choosing the amount of bandwidth assigned to its channel. In this paper we analyze rate reduction techniques for compressed video in terms of complexity and final picture quality. We propose a new scheme, working entirely in the frequency domain, for bit rate reduction of compressed video. It is a low delay and drift free video transcoder that outperforms a re-encoding system and performs very close to a normal encoder using uncompressed video.