Method of and system for transmitting and receiving digitally encoded video images

P.H.N. With, de (Inventor), S.J.J. Nijssen (Inventor), A.M.A. Rijckaert (Inventor), G.-J. Keesman (Inventor)

Research output: PatentPatent publication

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Abstract

Video images are encoded by transform coding, resulting in data blocks each including a DC-coefficient and a plurality of AC-coefficients. The coefficients of a number of said transform blocks are variable-length encoded and transmitted. In order to avoid a complete loss of datablocks in case of a transmission error, the most significant codewords of a group of blocks are transmitted first so as to achieve that at least the DC-level of the blocks is likely to be retained. The coefficients may also be recorded on a videorecorder. Fast playback of recorded images so encoded, leads to very poor quality because some data blocks are not being read in the search mode. To improve this quality the DC-coefficients and if desired predetermined AC-coefficients of selected ones of the transform blocks to be recorded on one track are packed together to form a DC-packet and such packet is recorded on a selected part of the track. The DC-packet is chosen such that it can be read out as a unit at various search speeds, and can be read partially at higher search speeds.
Original languageEnglish
Patent numberUS5,583,651
Publication statusPublished - 10 Dec 1996

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