Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Can ALAC/m4a detect file corruption? (Read 4974 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Can ALAC/m4a detect file corruption?

I have found amount of article, and know that flac/ape/tak can check audio integrity with inner crc info and outter md5.
ALAC/m4a is also open. But its format is so complicated (so many "box" type with different meta info), and I try to find crc or md5
in the format  structure detail description, and cant find them.

I have tried use an hex editor directly change some random bytes in middle of the alac file.
First time I change 2 position, [foobar 2000 - verify integrity] says it's ok. So the check tool cant detect this change.
Second time I change 2 more position, and this time the tool report :
"Reported length is inaccurate : 4:25.653333 vs 4:25.560454 decoded
Error: Decoding error: Unsupported format or corrupted file, frame: 2112 of 2861".

May there anyone know much about ALAC/m4a structure could tell me :
Can ALAC/m4a detect file corruption? (with inner metadata like crc/md5?or other mechanism?) O:)





Re: Can ALAC/m4a detect file corruption?

Reply #5
What methodologies or tools can be used to effectively conduct corruption tests on different audio formats, such as ALAC and TTA, and how do these methods compare? Thanks

Re: Can ALAC/m4a detect file corruption?

Reply #6
You can simply use a hex editor to either change, remove or add one byte, or a few, and listen what happens.
Music: sounds arranged such that they construct feelings.