第 页
西华大学毕业设计外文资料翻译
译文：
标题（四号宋体加粗、居中）
内容（小四宋体，行距1.25倍行距）
第 页
西华大学毕业设计外文资料翻译
原文：
标题（四号Times New Roman字体加粗、居中）
（内容为小四Times New Roman字体，行距1.25倍行距）
Error Control and Concealment for

Video Communication: A Review
The problem of error control and concealment in video communication is becoming
increasingly important because of the growing interest in video delivery over unreliable
channels such as wireless networks and the Internet. This paper reviews the techniques that
have been developed for error control and concealment in the past 10–15 years. These
techniques are described in three categories according to the roles that the encoder and
decoder play in the underlying approaches. Forward error concealment includes methods that
add redundancy at the source end to enhance error resilience of the coded bit streams. Error
concealment by postprocessing refers to operations at the decoder to recover the damaged
areas based on characteristics of image and video signals.Last, interactive error concealment
covers techniques that are dependent on a dialogue between the source and destination. Both
current research activities and practice in international standards are covered.
Keywords—Error concealment, error control in video transport,video communications.
I. INTRODUCTION
One inherent problem with any communications system is that information may be altered
or lost during transmission due to channel noise. The effect of such information loss can be
devastating for the transport of compressed video because any damage to the compressed bit
stream may lead to objectionable visual distortion at the decoder. In addition,
real-time/interactivity requirements exclude the deployment of some well-known
error-recovery techniques for certain applications. Last, issues such as audio-visual
synchronization and multipoint communications further complicate the problem of error
recovery.Transmission errors can be roughly classified into two categories: random bit errors
and erasure errors. Random bit errors are caused by the imperfections of physical channels,
which result in bit inversion, bit insertion, and bit deletion. Depending on the coding methods
and the affected information content, the impact of random bit errors can range from
negligible to objectionable. When fixed-length
coding is used, a random bit error will only affect one code word, and the caused damage