Source-driven packet marking for speech transmission over Differentiated-Services networks

We present a source-driven approach to packet marking for speech transmission over packet networks implementing the Differentiated Services model. Packets generated by the speech coder are examined: if deemed perceptually critical, they are marked as premium and sent on a "virtual wire;" otherwise, they are sent as regular best-effort traffic. Applied to speech coded with the ITU-T 8 kb/s speech coding standard G.729, the proposed source-driven packet marking scheme outperforms source-transparent techniques and provides clearly better perceptual quality than the unprotected case sending as little as 1/5 of the coded bitstream as premium traffic. Audio samples are available at http://demartin.polito.it/icassp2001/.