Apparatus for excising (and reinserting) specific data from a compressed video data stream to reduce its transmission bandwidth

In a digital video transmission system for transmitting a hierarchically layered compressed video signal wherein respective layers of compressed signal include headers containing data descriptive of said respective layers, one of such layers being a slice layer which includes a slice start code and a group of macroblocks of pixel representative information;

• said slice start code including an invariant portion and a variable portion, apparatus for segmenting said hierarchically layered compressed video signal into transport cells. respective transport cells containing a first predetermined number, N, of data bits divided between a transport cell header including a second predetermined number, K, of data bits and a payload of N-K compressed video signal data bits, said transport cell header data bits containing information for identifying compressed video signal data bits of corresponding payloads, said apparatus comprising:
• means for excising said slice start codes from said compressed video signal and for segmenting said compressed video signal with slice start codes excised into fixed length payloads and forming respective payloads into transport cells;
• and
• means for generating entry pointers indicating the relative location within respective payloads, of the location within the compressed video signal at which respective slice start codes were excised, and including said entry pointers within corresponding transport headers.

Receiver apparatus for receiving MPEG compressed video signal of the type arranged in transport cells, each of which includes a transport header and a payload containing a portion of said compressed video signal said compressed video signal having a slice layer of a plurality of slices, each of which originally included slice start codes, and said slice start codes being excised in the formation of respective pay loads, said apparatus comprising;

• a source of said transport cells;
• a source of slice start codes;
• means responsive to transport header data of respective transport cells for determining whether respective transport cells include the beginning of a slice of data, and the location of said beginning of a slice of data;
• means responsive to said transport cells for separating transport headers and payloads and responsive to a determination of the location of said beginning of a slice of data, for inserting a slice start code provided from said source of slice start codes;
• an MPEG video signal decompressor;
• and
• means for coupling payloads with slice start codes inserted therein to said MPEG video signal decompressor.

In a digital video transmission system for transmitting hierarchically layered compressed video signal in transport ceils, said hierarchically layered compressed video signal including a slice layer, respective slices including a slice start code and a plurality of blocks of data representing pixel information, and wherein respective transport cells include a transport header and a payload of a portion of said hierarchically layered compressed video signal from which respective slice start codes have been excised, and said transport header including entry pointer data related to the location in respective payloads from which said slice start codes were excised;

• receiver apparatus comprising:
• means for receiving transmitted said transport cells and separating said transport cell headers and payloads;
• means responsive to transport cell header data for providing data representing said slice start codes which were excised and inserting same in the compressed video signal locations from which said slice start codes were excised;
• and
• decompression means, responsive to said payload data with data representing said slice start codes inserted, for providing decorepressed video signal.