Low Punctured Turbo Codes and Zero Motion Skip Encoding Strategy for Distributed Video Coding

In this paper, we present a distributed video coding scheme based on low punctured turbo codes and zero motion encoding strategy. Most recent distributed video coding schemes have a common structure: the encoded bit streams consist of both side information derived from previous frames and syndrome bits derived from channel coding such as Turbo codes. Turbo codes are often punctured to generate scalable compressed video bit streams. We demonstrate in this paper that the generation of side information and the design of the punctured Turbo codes can be integrated to improve the overall coding performance. In the encoding of the video frames, zero motion blocks can be identified and made known to decoder so that the reference frames at the decoder shall have some blocks remain unchanged. While constructing the frame at the decoder, the Turbo decoder may be able to use this information as a constraint to achieve an improved performance. However, we discover a better way of making use of zero motion blocks by skipping the encoding of these blocks. The skip at the encoder will result in the direct reduction of the video coding bit rate as well as lower punctured Turbo codes. Since low punctured Turbo codes perform better, the combined effects on the reduced rate side information and an improved Turbo coding performance leads to an overall performance improvement. Simulation results based on this approach show that integrated low punctured Turbo codes and zero motion skip encoding strategy indeed achieves better performance than the constrained punctured Turbo coding. Furthermore, this scheme can be extended to other channel coding schemes, such as Product Accumulate code, that have been adopted in distributed video coding.