DCT-based video frame-skipping transcoder

Due to high computational complexity and quality degradation introduced by conventional frame-skipping transcoders, a DCT-based video frame-skipping transcoder is proposed recently. However, the transcoding process of the motion compensated macroblocks in the DCT domain becomes the bottleneck since IDCT and DCT processes are required. In this paper, we propose a new architecture of the frame-skipping transcoder to reduce the computational complexity of motion compensated macroblocks in the frame-skipping process. The new architecture transcodes the dominant region of an MC macroblock in the DCT domain by making use of the DCT coefficients from the incoming bistream and some pre-computed shifting operators. By using our proposed shifted version of the dominant vector, the re-encoding errors introduced in the dominant region can be avoided. On the other hand, an adaptive transcoding architecture to transcode the boundary of MC marcoblocks and to perform error compensation of MC macroblocks boundary is also proposed. Experimental results show that, as compared to the conventional transcoder and DCT-based transocder, the new architecture for frame-skipping transcoder is more robust to noise, gives rise to fewer requantization errors, and requires simple computational complexity.