Abstract: Decoding includes identifying a scan pattern by which the bitstream is decoded. A set index value is decoded from the bitstream that specifies a set of flags according to the scan pattern that contains a last significant coefficient flag of the significance map, and individual significance flags are decoded and the decoded values written into the significance map according to the scan pattern and including the specified set of flags. Encoding a significance map includes identifying a scan pattern by which the significance map is scanned to form a list of significant coefficient flags. Encoding identifies a group of significant coefficient flags including a last significant coefficient flag and referencing the identified group with a scan index value. The significance map is then scanned in accordance with the scan pattern up to and including an entirety of the identified group and the scanned flag values then encoded.

Abstract: Skipping reproduction of image data is performed while maintaining the continuity of a moving image before and after a skipping point, thereby preventing the video buffer in the decoder from failing. A moving image recording and reproducing apparatus for such skipping reproduction includes a decoder to decode an MPEG-2 video stream recorded on an optical disc and an encoder to re-encode the decoded video stream by editing. A multiplexer multiplexes the edited video stream and an audio stream, and an analysis controller controls the editing. To generate a multiplexed stream which can be reproduced by skipping from a first video stream to a second video stream, the analysis controller limits the re-encoding so that the bit occupancy in the video buffer is smaller than the capacity of the video buffer and larger than zero for a time period starting with the supply of the second video stream to the video buffer of the decoder and ending with the beginning of the decoding of the second video stream.

Abstract: An apparatus of the helical scan type for reproducing a digital video signal from slant tracks (T) on a record carrier, the digital video signal having been recorded in first track portions (TP1) of the tracks. In an edit mode, the digital video signal is reproduced from the first track portions and a corresponding digital audio signal is recorded in second track portions (TP2) of the tracks. The apparatus includes at least one read head (RH) for reading the digital video signal recorded in the first track portions of the tracks and at least one write head (WH) for writing the second channel signal in the second track portions. The read head (RH) and the write head (WH) are positioned on a rotatable head drum at such a location relative to each other that when the read head reads the digital video signal from a first track portion of a first track (T.sub.i+24), the write head writes the second channel signal in a second track portion in a second track (T.sub.