VLC does not open some MP3 files

[ImARandomUser]

Hi,

I went through a MP3 file I cannot open with VLC. However, opening it with Firefox will play it.

VLC gives an output too big for the forum, so here it is in an exported .log : https://www79.zippyshare.com/v/c2eSsdwa/file.html

And here the .mp3 file I wanted to play : https://www79.zippyshare.com/v/wbYbuadX/file.html

[Lotesdelere]

This not an MP3 file, this is OPUS in OGG.
Change the extension from .MP3 to .OGG and it will play.

[ImARandomUser]

Nice ! Thank you ! However, if the extension is wrong, why would Firefox still play it ?
Also, what line allowed you to deduce that ? Is that from personnal knowledge ? I tried looking in the logs before posting in order to find a solution by myself but did not really find any hint toward any other format (I don't know much either, so it might come from me).
Last, if you deduced it from personnal knowledge, where could I learn this kind of things ? Is there a way to automate wrong extension recognition and detect the right extension ?

[Hitchhiker]

It'll play in Firefox or any other browser because OPUS is an audio format developed for Internet streaming. That also provides a clue as to what the file format actually is in this particular case. The vlc log tells you what it's not which is an mp3.

From there it's a case of logical deduction I think. Since it's not an mp3 what else could is be? The most popular music streaming service these days is Spotify which streams in OGG Vorbis so that's where it most probably originated from. So changing the file extension from mp3 to OGG should work.

[Lotesdelere]

Media Info helps a lot for checking media files:
https://mediaarea.net/en/MediaInfo/Download/Windows

That said, older versions of VLC could play that kind of files with wrong extension by detecting the real content of the file, but unfortunately it seems that's not the case anymore

[Rémi Denis-Courmont]

MP3 is not a file format. It's just raw audio frames stitched together, maybe with some ID3 tags in front.

Due to this, a file can easily be mistaken as MP3 even if it is not (same problem as with MPEG-PS), and fail to play. The advantage is that this can recover corrupt file.