The present invention relates to digital video signal processing for recording or other transmissions and, more particularly, to receivers or monitors wherein loss of synchronization causes shifting of parts of the image generated by otherwise correctly decoded video signals.
Digital coding techniques are used to reduce the amount of data for storage and/or other types of transmission of digitized video information signals. Transform coding and variable word-length coding are among well-known techniques to obtain efficient data compression. These techniques are often combined.
Loss of synchronization is a key problem in variable word-length decoding of compressed data. In the case of transformed images that are coded with variable word-length codes, many pixel blocks may pass before re-synchronization takes place. Even after a return to synchronization, it may not be possible to put the correctly decoded data in the proper position in the picture. There is thus a distortion of the decoded picture due to a shift of data. This is shown in FIG. 1, where the top and bottom parts of a tree are clearly misaligned.