Video quality monitoring for mobile multicast peers using distributed source coding

We consider a peer-to-peer multicast video streaming system in which untrusted intermediaries transcode video streams for heterogeneous mobile peers. Many different legitimate versions of the video might exist. However, there is the risk that the untrusted intermediaries might tamper with the video content. Quality estimation and tampering detection are important in this scenario. We propose that each mobile peer sends a digest of its received video to a quality monitoring server which has access to the original video. The digest is a Slepian-Wolf coded projection of the received video. Distributed source coding provides rate-efficient encoding of the projection by exploiting the correlation between the projections of the original and received videos. Two different projections are designed for quality estimation and tampering detection, respectively. We show that the projections can be encoded at a low rate of just a few kilobits per second. Compared to the ITU-T J.240 Recommendation for remote PSNR monitoring, our scheme achieves a bit-rate which is lower by at least one order of magnitude.