Christoph Biedl wrote: > Frank Heckenbach wrote... > > > I got some MP3 files which were apparently created by LAME that > > "file" detects only as "data". > > > > I'm not completely sure if the files are valid, but apparently they > > are generated like this, and "ffprobe" and "mpv" do recognize them. > (...) > > It's been a while, and the problem is still there :-| > > It seems MPEG frames have a fixed size of 0x1a1 octets and so possibly > lame preprended an empty one, for whatever reason. From earlier > experience, players are fairly robust against data weirdness, hence this > still worked for you. > > While I could bring this upstream, I'd still like to learn more about > what happened here. Were you able to reproduce lame's behaviour with > arbitrary input?
I can't easily reproduce it. It occurs in some files I got from a customer. I suppose they probably created them on an MS-Windows (or possibly Apple) system, but I don't know details, and I can't easily find out since they were created in another department than I had contact with. It may even be some other software on their system that uses LAME internally and adds the empty frame, but since the number of zeros is exactly one MP3 frame, as you observed, I think this is done intentionally (by whomever), so all I can really say it that such files seem to exist in the wild, so it might be worthwhile to identify them. Since they are proprietary, I can't post an original file. I guess I could send one to you personally if that helps if you don't pass it on.
