METHOD OF INSERTING ADDITIONAL DATA INTO A COMPRESSED SIGNAL

摘要

Many compressed audio or video frames contain silence (if audio), or a blank image (if video); these essentially information content free (e.g. silent if audio or blank if video) frames can be both detected whilst still in compressed form and then used to carry the additional data. In an MPEG implementation, subbands associated with silent frames are rendered digitally silent and then used to carry PAD (Programme Associated Data).