Patent ID: 7634031

Claim:
A method performed by a watermark encoder apparatus for encoding symbols carrying payload data for watermarking therewith an audio or video signal, whereby said symbols can be recovered at decoding side and whereby at least one of said symbols and at least one synchronization block are combined to form a current watermark frame, said method comprising the steps: a) encoding, in said watermark encoder apparatus, said payload data and assigning a chronological identification data item ID to each one of said symbols; b) checking at encoder side whether or not a current one of said symbols can be correctly decoded in a corresponding decoder: if true, arranging in said watermark encoder apparatus said current symbol in said current frame together with said ID data item, and if said current frame has not been processed completely, continuing with step a), or if not true, skipping in said watermark encoder apparatus said current symbol in said current frame by arranging an empty symbol in said current frame that does not include the corresponding one of said ID data items, and if said current frame has not been processed completely, continuing with step a) using the ID data item that was intended for the symbol at the location of said empty symbol; c) after said current frame has been processed completely, outputting from said watermark encoder apparatus said current frame embedded in said audio or video signal, and continuing the processing with the next frame.