http://iet.metastore.ingenta.com
1887

Multimedia communications

More general concepts than this:

1-2 of 2 results

Filter by subject:

< Any subject

Filter by content type:

Filter by publication date:

Filter by author:

< Any author

Error robust video communications for wireless networks
Author(s): Z. Ahmad, M. Salman, S. Worrall, A. Kondoz
Source: 5th International Conference on Visual Information Engineering (VIE 2008), 2008, p. 524 - 527
Type: ConferencePaper
+ Show details - Hide details

Header compression increases the transmission throughput and improves the quality of service in error prone environments. ROHC (robust header compression) is an IETF (Internet engineering task force) standard, which is used to compress the network and transport headers to save the precious air interface of mobile communication systems. The U-mode of ROHC profile 1 is suitable for transmission of packets without a feedback channel. However, in error prone environments, ROHC U-mode may lose synchronization between the compressor and decompressor due to bursts of errors in wireless communications. This results in unnecessary packet loss, which has severe detrimental effects on video quality. In this paper, the causes of context damage are analyzed for U-mode, and its effects on H.264 video quality and packet loss are demonstrated. A scheme to minimize the occurrences of context damage is proposed. Using the proposed scheme, packet loss rate reduces significantly for ROHC U-mode.

Add to favourites
Export citations
A novel packetisation scheme for MPEG-4 over 3G wireless systems
Author(s): Z. Ahmad, S. Worrall, A.H. Sadka, A. Kondoz
Source: Fifth IEE International Conference on 3G Mobile Communication Technologies (3G 2004) The Premier Technical Conference for 3G and Beyond, 2004, p. 302 - 306
Type: ConferencePaper
+ Show details - Hide details

In this paper, a new packetisation method for MPEG-4 video packets is proposed and analysed. This packetisation method is based on a new header compression scheme to compress headers of MPEG-4 video packets for streaming over UMTS. MPEG-4 header compression not only makes more efficient use of scarce wireless bandwidth but it also improves the perceptual video quality and error robustness. In particular, it makes recovery from errors faster. MPEG-4 video packet headers contribute a significant portion of video packet size, particularly when resynchronisation, header extension code and data partitioning error resilience options are switched on. The new header compression scheme is aimed at reducing the MPEG-4 video packet overheads and optimising the packetisation method for enhanced robustness. Preliminary results obtained from the experiments for this approach show an improvement in objective quality of up to 5 dB, apart from the considerable savings in bandwidth. This paper focuses on the packetisation method for MPEG-4 video packets and features the improvements made for video quality achieved by the defined packetisation scheme.

Add to favourites
Export citations
Items per page 20 | 50 | 100
Print this page
This is a required field
Please enter a valid email address