A complexity scalable H.264 decoder with downsizing capability for mobile devices

It is significantly challenging to playback H.264 compressed video in real time on mobile devices with limited computing power. In this paper, we propose a complexity scalable H.264/AVC decoding algorithm with a downsizing capability, which can offer the complexity scalability by directly decoding the compressed video at a downsized resolution. In the proposed method, the predicted and residual signal can be generated in a downsized resolution by modifying the motion compensation (MC) and the inverse discrete cosine transform (IDCT). As a result, the computational decoding load can be significantly reduced. Moreover, the proposed H.264 decoder can achieve the complexity scalability by adaptively discarding (or simplifying) redundant computations which have larger complexity but less effect on the video quality. Experimental results show that the decoding complexity can be reduced up to 43%, as compared to the conventional H.264/AVC decoder, while maintaining the acceptable video quality.