P.Cherriman, L. Hanzo
Department of Electronics and Computer Science,
Univerity of Southampton, SO17 1BJ, UK.
Tel: +44 703 593125, Fax: +44 703 593045
© 1996 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to refuse any copyrighted component of this work in other works must be obtained from the IEEE.
Presented at IEEE ICCS'96 / ISPACS'96, 25-29 November 1996, Singapore, pp. 1369-1373 (Volume 3).
The video quality versus bitrate performance of the H.261 and H.263 codecs is characterised and a bitrate control algorithm is proposed in order to maintain a selectable near-constant video bitrate. The source codecs are operated at four different bitrates, which result in a constant symbol rate after error correction coding. This system constellation allowed us to maintain a constant video user bandwidth requirement, but benefit from improving channel conditions in terms of better video quality, when invoking more bandwidth efficient modem schemes ranging from 1 to 6 bits per symbol.