| 摘要 |
<p>The invention is concerned with decoding and re-encoding compressed audio signals using an auxiliary signal containing information relating to coding decisions and, in particular, using a signature to detect changes in the decoded signal which would render the auxiliary signal of little or no use in re-encoding. A compressed audio signal is decoded 10 and the auxiliary signal extracted and forwarded to an encoder 20 where the decoded signal is re-encoded after studio processing. The auxiliary signal contains signature information calculated by the decoder, e.g. a checksum or mean signal level, which is compared to a signature derived at the encoder. If the signatures match within a threshold, re-encoding is performed using the auxiliary information, otherwise all or part of the auxiliary signal is ignored ("blind" re-encoding). The auxiliary signal may be communicated separately (as shown) or with the decoded audio signal.</p> |
