| Summary: | 碩士 === 國立中央大學 === 電機工程學系 === 85 === ABSTRACT H.263 is a very low bit-rate video coding standard
which has been used with modem and wireless transmissions.
Although the video coding output is naturally variable bitrate
(VBR), the channel delivering the video stream is often constant
bitrate (CBR). Thus, the rate control which converts the VBR
video into CBR streams is necessary. We present an adaptive rate
control algorithm which achieves CBR by adjusting the
quantization stepsize. Experiment results show that the
algorithm can effectively maintain CBR. In addition, The error
propagation caused by transmission errors may seriously
deteriorate the video quality. We present here an efficient
error concealment with macro-block interleaving technique for
H.263 video. At the transmitter, macro-blocks of I-pictures and
P-pictures are interleaved to preserve adequate information for
performing efficient error concealment. At the receiver, de-
interleaving and effective error concealment techniques are
utilized for reducing error damage. Our simulations reveal
satisfactory performance.
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