SIGNAL ENCODING

摘要

The invention relates to a signal encoding system ( 100 ). A pre-encoder ( 103 ) encodes a signal and generates a pre-encoded signal. In addition the pre-encoder ( 103 ) generates encoding assistance data which is stored in a signal storage ( 105 ) together with the pre-encoded signal. When the signal is retrieved from the signal storage ( 105 ), it is decoded in a decoder ( 111 ) and a watermark is inserted in the decoded signal to generate a watermarked signal. The watermarked signal is then re-encoded, possibly at a different encoding rate, in a re-encoder ( 117 ). The re-encoder ( 117 ) is operable to re-encode the watermarked signal in response to the encoding assistance data. Thus, encoding assistance data may be generated at encoding prior to storage and the encoding assistance data may be used to facilitate re-encoding of a watermarked signal when retrieved. The invention is particular advantageous for applications wherein pre-encoding is performed once whereas re-encoding is frequently performed, such as for example a client-server music download application.