[linux-audio-user] AC3 file structure question

I have a large AC3 file: $ file chicken.ac3 chicken.ac3: ATSC A/52 aka AC-3 aka Dolby Digital stream, 48 kHz,, complete main (CM) 3 front/2 rear, LFE on,, 448 kbit/s reserved Dolby Surround mode I want to create a much smaller file with the same parameters, ideally silent, with a duration of about 2 sec, then concatenate the small file at the beginning of the existing large file. If I'm not mistaken, an AC3 file is made out of independent frames of fixed size. Is that correct? If yes, what is the size of a frame? If the frames are fixed-size, I could simply use dd to generate a small fragment out of the existing file, then use cat to glue the fragment and the original file. -- Florin Andrei http://florin.myip.org/