Video Quality Evaluation for Wireless Transmission with Robust Header Compression Fourth International Conference on Information, Communications & Signal Processing Fourth IEEE Pacific-Rim Conference On Multimedia 15 -18 December 2003, Meritus Mandarin Hotel, Singapore Seeling, Fitzek, Reisslein
Content n Introduction & Motivation n Header Compression Schemes n Robust Header Compresion (ROHC) RFC 3095 n Video over ROHC n n n Methodology and Testbed Setup Results Conclusion Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Introduction n n Video services over wireless networks are gaining more and more interest Services are needed that convince customers to buy new equippment (e. g. , 3 GPP networks) 3 GPP networks support video services such as the IMS and the MBMS entities Problem: Video services need much more bandwidth than voice calls, which makes them hard to sell Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Motivation n n Video services are transmitted over IP networks using the RTP/UDP/IP protocols Video is encoded efficiently, but the protocol stack overhead is not The protocol overhead comprises a large portion of the traffic (even more for small video formats as for the mobile phones) Therefore: Compression of the protocol overhead needed Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
General Structure of Header Compressors n Two entities: compressor and decompressor n Compressor sends initial base n Base is used by compressor and decompressor n Compressor removes redundancy n Decompressor adds removed information n Proposed solution differ in a possible feedback channel Base N Compressor N* Decompressor Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia N
IP Header Compression n IP HC RFC 2507 provides only rudimentary support for UDP with low compression CRTP has problems with high loss rates and delays (bandwidth-delay product) Overall: problems with previous header compression schemes over wireless links Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Robust Header Compression (ROHC) RFC 3095 n General ROHC header compression scheme n Single hop and stateful n Dynamic state and context changes Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Robust Header Compression (ROHC) RFC 3095 n Context states: n No context: largest ROHC header for context establishment n Static context: context for static parts exists n Full context: all parts are within the established context Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Robust Header Compression (ROHC) RFC 3095 n ROHC modes based on feedback availability n Unidirectional mode (no feedback) n n n Periodic context state updates Fallback to lower states upon minor changes Bi-directional optimistic mode n n n Decompressor ACKs context changes NACK based context updates triggered by decompressor Bi-directional reliable mode n Closest coupling between compressor / decompressor Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Methodology n Uncorrelated bit errors as recently found for UMTS channels n Simulated with and without ROHC implementation n O-Mode Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Metrics n n Peak Signal to Noise Ratio (PSNR) for quality comparison Header Compression, total compression, and mean ROHC header size Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Testbed Setup Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
PSNR Measurements n n n PSNR calculation is standard metric for objective video quality measurements Freezing for lost frames Video. Meter tool for visualization Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Netmeter Tool Bandwidth w/o ROHC Bandwidth with ROHC Header compression Overall compression Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
ROHC Results n Table of Compression Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Insights n n Protocol header compression can be achieved by using ROHC Higher compression ratios for smaller video formats and higher quantization n n Lower fraction of packets comprised of actual video data (i. e. , payload) Lower error probability and state changes within ROHC Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
ROHC Results n PSNR Figure Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Conclusion n ROHC is an efficient header compression scheme for multimedia in wireless environments Compression achieved depends on video format and video content Utilization of ROHC for multimedia streaming does not introduce additional losses in terms of perceived video quality (PSNR) Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Q/A Thank you! patrick. seeling@asu. edu fitzek@acticom. de reisslein@asu. edu Am Borsigturm 42 13507 Berlin Germany www. acticom. de The only situation we recommend to be wired! Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
Related Work n n F. H. P. Fitzek, S. Hendrata, and M. Reisslein, "Header Compression Schemes for Wireless Internet Access", in Wireless Internet: Technologies and Applications, Series: Electrical Engineering & Applied Signal Processing Series, 2004 F. H. P. Fitzek, S. Hendrata, P. Seeling and M. Reisslein, "Video Quality Evaluation for Wireless Transmission with Robust Header Compression", Technical Report: acticom-03 -003, acticom Gmb. H, Germany, July, 2003 P. Seeling, F. H. P. Fitzek, and M. Reisslein, "Video. Meter tool for YUV bitstreams", IEEE Network Magazine, software tools for networking, Vol. 17, No. 1, January 2003 S. Rein, F. H. P. Fitzek, and M. Reisslein, "Voice Quality Evaluation for Wireless Transmission with ROHC", International Conference on Internet and Multimedia Systems and Applications (IMSA 2003), pages 461 -466, August 13 -15, 2003, Honolulu, USA Fourth International Conference on Information, Communications & Signal Processing, Fourth IEEE Pacific-Rim Conference On Multimedia
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