An Evaluation of Video Compression Schemes for Teleteaching Applications

Abstract

Synchronous, interactive teleteaching is demanding with respect to required network bandwidth and short end-to-enddelays. An uncompressed digital video, e.g., requires a data rate of 261 MBit/s. Video compression is a methodto reduce required network bandwidth. Efficient video compression is almost lossless with respect to perceivedvideo quality at the receiving site, but it is time intensive. In support of interactivity, however, response times mustbe short to allow participants to audio-visually communicate like being in the same room. This implies that the end-to-end communication delay should be less than 150 ms. This requirement puts a hard constraint on videocompression since compression time is only one factor that adds to the overall end-to-end delay. We present aframework for the evaluation of video compression schemes. We define evaluation criteria such as compressiondelay and compression efficiency. The video compression schemes evaluated are Motion JPEG, MPEG, H.261 andH.263.