CRC for existing mp3
Reply #7 – 2006-02-14 08:37:22
You may ask the coder of "mp3repacker" (omion) whether he's willing to add this functionality.[a href="index.php?act=findpost&pid=363875"][{POST_SNAPBACK}][/a] No. @zz1: It would be possible to do (*), but as others have said, this is of limited functionality, as it only checks ~34 bytes of each frame. There are over 1000 bytes of audio data in a 320kbps frame, so the CRC won't help a whole lot. If you're worried about errors, I'd just make a PAR2 file from all the MP3(s) in the directory. I'm actually in the process of making a PAR2 of a bunch of stuff to be burnt to a DVD (6 hours left... it's not fast)Sorry for this n00bish question... If I have two mp3's that foobar reports that they are 192kbps and one have CRC checksum and the other does not than the file with CRC will have worse quality (will really have lower bps for audio data)? The maximum possible quality will be higher with the one without CRCs. What quality they actually are depends, of course, on the encoder. BTW, my repacker will strip off the CRCs, in case you want to save a couple of KB on that file. (*) There are some encoders (FhG?) which don't pad correctly. There are plenty of wasted bits, but my mp3repacker can't reach them. It would probably need a Huffman repacker to get out (which I'm not going to make). A 320kbps file encoded this way won't have enough space for the CRC. Other than that, I've never run into a file which you couldn't add 2 bytes per frame, even the CBR320 ones.