Implementation of an Adaptive Stream Scaling Media Proxy with the data path in the Linux Kernel

Abstract

Streaming media is becoming increasingly common, and bandwidth demands are rising. Centralized distribution is becoming prohibitively hard to achieve and geographically aware hierarchical distribution has emerged as a viable alternative, and has brought with it an increased demand for CPU processing power.

There has also been an influx in an abundance of different devices on which to receive media - from HD plasma screens to 2" cell phone displays - and the need for media to be able to adapt to devices of differing capabilities are becoming obvious.

For this thesis we have implemented a media proxy using RTSP/RTP. It is implemented partially in kernelspace, which has drastically reduced the CPU-cost of relaying data from a server to multiple clients. This has been combined with a proof-of-concept implementation for adaptively scaling a SVC media stream according to available bandwidth.