Compression improvement option in baseline H.263 video compression codec
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Date
2003-05
Authors
Senapen, Mohanavelu Mudaliar
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Abstract
Video conferencing systems are currently an active area of research. Standards
like H.323 have been developed to meet the requirement of a video conferencing
environment. Part of the main issue involved is video compression. Due to the
active interest in this area, many standards for video compression such as ITV-T
H.261, H.263,ISO/IEC MPEG-1, MPEG-2 and, MPEG-4 has emerged. As for video
cbnferencing requirements H.263 under H.323 umbrella standard is' a video
compression standard specified by the lTV -T for low bit rate communication
documented under infrastructure of audiovisual services in coding of moving video.
H.263 is an extension of H.261 compression algorithm with additional option, and
currently lTV is working on H.263+ with additional of 12 new negotiable optional
modes to improve the present codec requirements. Due to the interest shown in this
standard body for improving the present algorithm, it is quite evident that.
improvement in video compression is necessary.
This work discusses the modification in baseline H.263 coding algorithm to
improve the compression ratio of a given motion video data to suite low bandwidth
network. At this higher compression ratio, the quality of the video deteriorates
slightly due to the extra step introduced but to a user acceptable level. The
compression is improved by quantisizing the image sequence with a modified e-Iaw
logarithmic quantization prior to DCT transformation to reduce the number of bits in
a H.263 compression environment. High compression ratio is important because
ยท H.263 is developed primarily for video conferencing environmertt in a packet
switched network. It is optimized for low data rates and relatively low motion. We
are proposing the outcome of this research as another option for the present baseline
H.263 compression scheme.
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Standards like H.323 have been developed , to meet the requirement of a video conferencing environment.