I had an MP3 file with 17356655 samples of length and after inserting Enc delay of 576 my file has a 17316911 length, that means it's 39744 samples shorter (576*69), with other files the new length of MP3 is always shorter by a variable number (bigger with a long mp3, smaller with a short mp3) of samples that's alway a multiple of 576 but I cannot understand why... I thought that after inserting Enc delay the length of the mp3 would have been only 576 samples shorter and not shorter by a multiple of 576 samples... why?