CAJ | 학술논문

分布式视频编码系统中，现有码率控制方法大致分两类，一种是基于反馈信道，另一种是基于无反馈信道。基于反馈信道码率控制算法虽然可以获得较高的解码质量，但是时延大；相反，无反馈信道码率控制算法时延小、实时性高，但是有损解码质量。为解决这一矛盾，阐述一种混合码率控制算法，即在编码端先估计出较小的码率，当解码失败时，解码端才利用反馈信道向编码端请求更多的校验比特直到解码成功。实验结果表明，在相同目标码率下，与有反馈码率控制算法相比，该算法所需反馈次数有所减少；与现有无反馈码率控制算法相比，对于不同视频序列解码帧的峰值信噪比均有不同程度的提高。
분포식시빈편마계통중，현유마솔공제방법대치분량류，일충시기우반궤신도，령일충시기우무반궤신도。기우반궤신도마솔공제산법수연가이획득교고적해마질량，단시시연대；상반，무반궤신도마솔공제산법시연소、실시성고，단시유손해마질량。위해결저일모순，천술일충혼합마솔공제산법，즉재편마단선고계출교소적마솔，당해마실패시，해마단재이용반궤신도향편마단청구경다적교험비특직도해마성공。실험결과표명，재상동목표마솔하，여유반궤마솔공제산법상비，해산법소수반궤차수유소감소；여현유무반궤마솔공제산법상비，대우불동시빈서렬해마정적봉치신조비균유불동정도적제고。
Recently, there are almost two approaches of rate control in distributed video coding, namely rate control with and without feedback channel. Although we can get a higher quality image through the former , it can cause much time delay. Oppositely, rate control without feedback channel will decode frame fast, but it may cause failure frame at the decoder. To solve the problem, this paper proposes a way of hybrid rate control, which will make a rate estimation at the encoder firstly. Once decoding failure, the decoder will request more parity bits from the encoder with feedback channel. Simulation results show that the proposed method will decrease the number of request by the decoder compared with the rate control based on feedback channel and get a high PSNR value compared with the current rate control without feedback channel.