Media-Aware Network Elements on Legacy Devices
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This document discusses implementing media-aware network elements (MANEs) on legacy devices to perform real-time adaptation of scalable video coded (SVC) bitstreams. It proposes using an ordinary WiFi router to intercept and adapt SVC streams in-network using a proxy approach. Evaluations show the router's CPU can support 4 parallel SVC streams with under 30% load and delay under 100ms, showing MANEs are feasible on existing home network devices.
Media-Aware Network Elements on Legacy Devices
- 1. Media‐Aware Network Elements on Legacy Devices m16695 Ingo Kofler, Robert Kuschnig, and Hermann Hellwagner Chris:an Timmerer Klagenfurt University (UNIKLU) Faculty of Technical Sciences (TEWI) Department of Informa:on Technology (ITEC) Mul:media Communica:on (MMC) h;p://[email protected] h;p://[email protected] mailto:chris@an.@[email protected]‐klu.ac.at Acknowledgement: Part of this work is supported by the European Commission in the context of the and ENTHRONE (contract no. 038463) project. Further informa@on is available at h;p://www.ist‐enthrone.org.
- 2. Outline • Mo@va@on and Introduc@on • List of Technologies • Architecture and Performance Evalua@ons • Demo Video • Conclusions / References 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 2
- 3. Mo@va@on and Introduc@on • Adapta@on of an SVC bitstream – Achieved by removing certain NALUs ➙ filtering of NALUs – Steered by a (TID, DID, QID) tuple ➙ filter criteria – Computa@onally cheap (compared to transcoding etc.) • Idea – Perform real‐@me in‐network adapta@on of the SVC bitstream on an ordinary, low‐cost WiFi router – Media‐aware Network Element (MANE) • Applica@ons of in‐network adapta@on – Cross‐layer adapta@on on the access point – Adapta@on for different end‐devices 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 3
- 4. Media‐aware Network Element On‐the‐fly adapta@on of scalable coded video content in a media‐ aware network element (MANE). Source: h;p://ip.hhi.de/imagecom_G1/savce/ 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 4
- 5. List of Technologies • Scalable Video Coding (SVC) • Real‐@me Streaming Protocol (RTSP) – Establishing and controlling the streaming session – VCR‐like control of the streaming (Start, Stop, Pause) • Real‐@me Transport Protocol (RTP) – Encapsulates the video and/or audio content – Mostly used on top of the unreliable UDP protocol – Offers sequence number, @mestamps for syncing the playback – Generic header with content‐specific payload format (AVC, SVC, …) 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 5
- 6. Proxy Approach server router with proxy router client RTSP RTP/RTCP RTSP RTP/RTCP RTSP RTP/RTCP TCP UDP TCP UDP TCP UDP IP IP IP MAC/PHY MAC/PHY MAC/PHY • Proxy on network device between client & server – Intercepts the RTSP / RTP communication – Proxy is transparent for the client – Acts as client for initial server and as server for the client • Implications – Proxy has to modify parts of the request (e.g. port numbers) – Proxy can then adapt the SVC video stream carried over RTP 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 6
- 7. Proxy Approach (cont’d) Benefits Drawbacks • Session‐ and stream‐/ • Proxy is running as user‐ media‐awareness space process • Enables stateful inspec@on • RTP packets have to be and processing of packets passed (copied) from the • Allows adapta@on on a per‐ kernel‐space to the user‐ session basis space and vice versa • Consistent RTCP receiver • Decreases theore@cal and sender reports throughput compared to kernel‐internal solu@on (e.g. filtering on IP level) 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 7
- 8. Architecture Handles incoming RTSP requests (554 redirect to proxy using iptables) SDP stored in LRU‐based cache un@l session established Maintains state: seq#, @mestamps, SVC params, monitoring, etc. Forwards non‐SVC packets Adapts SVC packets Acts as server for client Acts as client for server Retrieve monitoring informa@on Modify adapta@on/SVC parameters 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 8
- 9. Performance Evalua@ons • Hardware: Linksys WRT 54 GL – Broadcom System‐on‐Chip BCM5352EL – MIPS32 200 MHz CPU – 16 MB RAM – 4 MB Flash Memory – IEEE 802.11b/g WLAN – Fast Ethernet switch with 5 ports – price ~ 45 Euros (May 2008) • Sonware: OpenWrt – Linux‐based firmware for Broadcom‐based WiFi routers – gcc-based SDK for OpenWrt available – Proxy implementa@on in ANSI C 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 9
- 10. Performance Evalua@ons (cont’d) • Evalua@on of the implementa@on on the target plaporm – Server – proxy – client deployment – Inves@ga@on of worst‐case scenario (no adapta@on) • Performance metrics – CPU usage for different number of streams – Delay introduced by the proxy on a complete access unit (frame) • Three different SVC streams for evalua@on – Foreman, CIF, 30 Hz, 715 kbps – City, 4CIF, 30 Hz, 1247 kbps – Harbour, 4CIF, 30 Hz, 2056 kbps 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 10
- 11. Performance Evalua@ons (cont’d) CPU Usage 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 11
- 12. Performance Evalua@ons (cont’d) CDF of delay for sequence city (1245 kbps) 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 12
- 13. Demo Video 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 13
- 14. Conclusions • Proxy approach for in‐network adapta@on on a per‐packet basis – Aware of sessions and individual streams (media‐aware) – Stateful, not a simple packet dropper • Applica@ons – Adapta@on according to device capabili@es – Cross‐layer adapta@on – NAT traversal • Performance sufficient for typical home deployments – 4 parallel streams with 30 percent CPU load and < 100 ms delay ➙SVC adapta@on can be done on exis@ng off‐the‐shelf network devices 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 14
- 15. References • I. Kofler, J. Seidl, C. Timmerer, H. Hellwagner, I. Djama and T. Ahmed, “Using MPEG‐21 for cross‐layer mul@media content adapta@on”, Journal on Signal, Image and Video Processing, Springer, vol. 2, no. 4, Dec. 2008. • R. Kuschnig, I. Kofler, M. Ransburg, H. Hellwagner, “Design op@ons and comparison of in‐network H.264/SVC adapta@on”, Journal of Visual Communica@on and Image Representa@on, Sept. 2008. • I. Kofler, M. Prangl, R. Kuschnig, and H. Hellwagner, “An H.264/SVC‐based adapta@on proxy on a WiFi router”, Proceedings of the 18th Interna@onal Workshop on Network and Opera@ng Systems Support for Digital Audio and Video (NOSSDAV 2008), Braunschweig, Germany, May 2008. • I. Kofler, C. Timmerer, H. Hellwagner, and T. Ahmed: “Towards MPEG‐21‐ based Cross‐layer Mul@media Content Adapta@on”, Proc. 2nd Interna@onal Workshop on Seman@c Media Adapta@on and Personaliza@on (SMAP 2007), London, UK, Dec. 2007. 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 15
- 16. Thank you for your a;en@on ... ques@ons, comments, etc. are welcome … Ass.‐Prof. Dipl.‐Ing. Dr. Chris@an Timmerer Klagenfurt University, Department of Informa@on Technology (ITEC) Universitätsstrasse 65‐67, A‐9020 Klagenfurt, AUSTRIA chris@an.@[email protected]‐klu.ac.at h;p://[email protected]/ Tel: +43/463/2700 3621 Fax: +43/463/2700 3699 © Copyright: Chris.an Timmerer 2009/07/01 Chris@an Timmerer, Klagenfurt University, Austria 16