K.P. Subbalakshmi and Q. Chen (USA)
Multimedia over Wireless Networks, MPEG-4 video over wireless channels, joint source-channel coding, error resilient multimedia communication.
MPEG-4 video coding standard  is one among the
current state of the art techniques in video compression.
This paper addresses the issue of reliable transmission of
MPEG-4 video over wireless channels. This becomes an
especially important issue for MPEG-4 video, because it
uses variable length codes as part of its compression
algorithm and although variable codes are often used for
better compression, they are also extremely vulnerable to
noise introduced by the channel. This paper presents a joint
source-channel coding approach to achieving reliable
transmission of MPEG-4 video over wireless channels. We
present a maximum a posteriori probability based, joint
source-channel decoder for the inter-coded macroblocks in
an MPEG-4 encoded video stream. Although MPEG-4
contains several error resilience features like reversible
variable length codes etc, we believe that our method could
provide additional error resilience to the MPEG-4 stream.
Our experiments indicate that the performance of the
proposed decoder is superior to the standard MPEG-4
decoder both perceptually and in terms of the peak signal to
noise ratio. In some case, our decoder does about 10 dB
better in terms of PSNR.