Fast transcoding for video delivery by means of a control stream

When a video delivery system provides different representations of the same sequence, solutions can be found in simulcast coding, scalable coding, and transcoding. The major downside of transcoding is the additional complexity needed to re-encode the video sequence in its new form. When one fidelity version of the video stream should be transmitted over the network, scalable coding is less efficient compared to single layer coding because of the layering overhead. Finally, simulcast encoding results in large storage requirements. In this paper, we propose an intermediate solution providing transcoding at a low complexity by the aid of control streams. We define a control stream as a regular video stream from which residual information is removed. With these control streams, the complexity of the encoding step in the transcoder can be reduced to decoder complexity. As a result of the removal of residual information, these control streams take up 62.8% less bitrate compared to simulcast coding for a test set based on High Efficiency Video Coding (HEVC). Additionally, when compared to scalable coding, an efficient single layer video stream can be provided without the 16.6% bitrate increase caused by transmitting a layered bitstream.