Inverse Bit Plane Decoding Order for Turbo Code Based Distributed Video Coding

For turbo code based Wyner-Ziv codecs, we propose to use an inverse bit plane decoding order. The investigations have shown that the knowledge about MSB´s has only a marginal influence on LSB´s, which can be regarded as noise, while the influence of LSB´s on MSB´s tends to be higher. As a results, we obtain a coding gain of up to 0.3 dB, especially for the sequences, which can only be decoded with a coding efficiency lower than H.264/AVC intra. Furthermore, the distribution of the requests for additional parity bits over the back channel is different compared to the conventional decoding order, resulting in a high number of requests for the last bit plane and a low number of requests for the other bit planes. Therefore, the decoder can request several puncturing levels for LSB´s in one step, reducing the number of turbo decoding loops. Hence, transmitting the LSB´s first, we can obtain a decoding speedup of 30%, thus making DVC more attractive for real-time applications.