| 摘要 |
<p>The present invention relates to the encoding of video signals comprising input digital words to produce a compression encoded output signal. In a television studio environment, it is conventional to generate digital television signals in which the picture information is conveyed by a digital signal consisting of digital words which are 10 bits in length. MPEG standards which apply to the transmission and reception of digital television signals require conformance to a word length of 8 bits. As a result, it is necessary to truncate the 10 bit digital words to 8 bits before compression encoding the signal in a standard encoder ready for transmission to a receiver. In the invention, the input digital words are truncated and compression encoded to produce an output compression encoded signal and the output compression encoded signal is then decoded so as to reconstruct the truncated words. A helper signal is then generated as a function of the difference between the input digital words and the reconstructed words. A receiver may be provided with the facility both to receive and decode the compression encoded signal and to combine the resulting decoded signal with the helper signal so as to improve the signal to noise performance of the transmission. <IMAGE></p> |
