H.264/SVC Adaptation on a WiFi Router


Recent advances in video coding technology like the scalable extension of the MPEG-4 AVC/H.264 video coding standard (H.264/SVC) pave the way for computationally cheap adaptation of video content. In the course of our research we developed a lightweight RTSP/RTP proxy that enables in-network stream processing. Based on an off-the-shelf wireless router (Linksys WRT 54 GL Broadband Router) that runs a Linux-based firmware we demonstrate that the video adaptation can be performed on-the-fly directly on a network device. By utilizing the RTP packetization of the video stream the proxy can adapt the video in the spatial, temporal and SNR domains. The proxy was developed from scratch in ANSI C and was deployed on the router by using the popular openWrt distribution.

Demo Setup

The demo setup consists of three major compontents:

  • The server (notebook on the left hand side) is a Linux-based machine that runs a Darwin Streaming Server which was extended by H.264/SVC support. The server streams the scalable video stream by using the RTP protocol. On the server there also runs a monitoring dashboard that visualizes the impact of adaptation on the network conditions. Besides, a control application for the adaptation proxy is also deployed on the server machine. This control application allows for selecting the adaptation parameters that are used for steering the adaptation on the adaptation proxy.
  • The router that runs the adaptation proxy is connected to both the server and the client via Ethernet links. The adaptation proxy adapts the video stream that is streamed by the server and forwards it to the client. The adaptation can be steered by a SOAP-based interface, which is used by the control application to set the parameters externally.
  • The client on the right hand side receives the (possibly) adapted video stream and renders it on the display. An experimental player which makes use of the SVC reference software of the decoder is used for decoding and rendering the video at the client.

During the course of the demo the client requests a video stream that will be adapted on the router. The impact of the adaptation can be seen both on the client (quality variation) and on the monitoring dashboard (bandwidth reduction). In addition to adapting a single session, we demonstrate the adaptation of two parallel sessions with different adaptation parameters.

Download a Video of the Demo

Title Format Size Link
Adaptation of single and parallel sessions (long version) 720p, H.264/MP4 380 MB Download
Adaptation of single and parallel sessions (long version) 720p, WMV 270 MB Download
Adaptation of parallel sessions (short version) 720p, H.264/MP4 220 MB Download
Adaptation of parallel sessions (short version) 720p, WMV 132 MB Download

For the playback of the videos we recommend the VLC media player.

Related Publications

I. Kofler, R. Kuschnig, and H. Hellwagner, "In-network Real-time Adaptation of Scalable Video Content on a WiFi Router", Proceedings of the 6th IEEE Consumer Communications and Networking Conference (CCNC09), Las Vegas, Nevada, US, January 2009. PDF

I. Kofler, M. Prangl, R. Kuschnig, and H. Hellwagner, "An H.264/SVC-based adaptation proxy on a WiFi router", Proceedings of the 18th International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2008), Braunschweig, Germany, May 2008. PDF


For more information please contact:

Dipl.-Ing. Ingo Kofler
Multimedia Communication Group (MMC)
Institute of Information Technology (ITEC)
Faculty of Technical Sciences (TEWI)
Klagenfurt University, Austria