Patent ID: 7334176

Claim:
Method for determining whether a data frame that is part of a bitstream (IP), besides coded ISO/IEC 11172-3 Layer III, ISO/IEC 13818-3 Layer III or ISO/IEC 13818-7 standard data denoted mp3 data, contains mp3PRO-coded additional data denoted mp3PRO data, wherein said standard data include header data, side information data and main information data in corresponding data fields of said data frame, and can include an ancillary data field, and wherein said additional data, if present, are arranged in a data field within said ancillary data field and include specific error protection data (ADCRC) together with specific main information data (CRCD) that are protected by said specific error protection data, and/or include specific identification data (ADH), such as specific header or specific sync data, and wherein no address value is provided in said bitstream for directly determining the begin or the end of said additional data field, but the begin of said additional data field would be determined after decoding said standard data, and wherein said side information data can include address information (main_data_begin) pointing to the beginning of the main information data field contained in the data frame preceding said current data frame, and wherein said ancillary data field is adjacent to said main information data field border but said additional data field is not necessarily fully occupying said ancillary data field and said additional data field is not adjacent to said main information data field border in case said additional data field is not fully occupying said ancillary data field, characterised by the steps: a) obtaining (CRFS) for audio decoding the encoded data of at least a transmitted current data frame; b) searching (MMPHSC, MMPCRCCA, MMPCRCCP), without decoding said main information data, said current data frame for: b1) identification data that match said specific identifi-cation data (ADH), or b2) data that, when performing on it a predetermined error protection scheme, match said specific error protection data (ADCRC), or b3) the items under b1) and, if successful, the items under b2), wherein said searching in said current data frame does not stop at its end but when reaching the pointed beginning of the main information data field; c) if a match under b1) or under b2) or a double-match under b3) has been found for said data frame, determining (RS, MPPDS) that said bitstream (IP) contains said coded additional data, or if a match under b1) or under b2) or a double-match under b3) has not been found for said data frame, determining (RS, MPPDS) that said bitstream (IP) does not contain said coded additional data.