Postprocessing for decoding without update step in motioncompensated lifted wavelet video coding Motioncompensated temporal filtering is an openloop coding technique, which generally employs a motioncompensated update step. Although the update step is essential at the encoder for good ratedistortion efficiency, it might be skipped at the decoder for benefits like lower complexity and lower playout delay. Previous investigations showed that skipping the update step at the decoder results in some quality degradation at high rates. In this paper we analyze how this degradation arises and also propose a simple method to reduce this degradation. The proposed solution can also be implemented as a postprocessing procedure after conventional decoding without the update step. Experimental results show that the degradation in quality is reduced by half. For our t2D wavelet coder, this gives a gain of xe2x88xbc1.0  1.5 dB at high bitrates.

Embedded to lossless coding of motion compensated prediction residuals in lossless video coding Lossless video coding is useful in applications where no loss of information or visual quality is tolerable. In embedded to lossless coding an encoded video stream can be decoded into any bit rate up to the lossless bit rate, which is quite useful in numerous applications. In this paper, the research we present is based on lossless video coding, which uses motion compensated prediction to eliminate temporal redundancy. We specifically address the problem of embedded to lossless coding of the motion compensated prediction residuals. Since the statistical properties of the residuals are different from still images, the best wavelet bases for still images do not perform well for residuals. Since residuals contain a higher portion of high frequency information in high motion regions, a fixed transform for the entire frame is not very efficient. We introduce a spatially adaptive wavelet transform method, which takes the local frame statistics into account before choosing the wavelet base. This transform technique provided the best performance for most of the test frames.