Re: [mpg123-users] libmpg123 opens non-mp3 files

[Thomas O. <tho...@or...>]

Am Tue, 19 Dec 2023 22:58:06 +0100
schrieb Guido Jäkel via mpg123-users <mpg...@li...>: 

> I would like to suggest to use the 'file' command to detect the MIME
> type of the audio files first.

Libmpg123 tries as hard as it can to extract something out of the data
you give it. This includes all kinds of weird historically used formats
including MPEG data with a leading RIFF header suggesting it's a WAV
file. This might confuse the 'file' tool, too.

But for regular files that don't try to be funny, where a header for WAV
or OGG Vorbis really means that, file, or, respectively, libmagic when
used in your own program, is a good way to pre-filter files.

MPEG audio is a bit special in that it doesn't specify a container
format with clear identification. It's a stream of raw frames and
metadata got tacked on later.

So maybe it's more sensible to check if it is something else known
first, as OGG etal. are easily identified, and only after that throw
libmpg123 on it.

Oh, you can also just use libsndfile for all your audio reading, as
current libsndfile has MP3 read and write support via libmpg123 and
liblame. Libmpg123 is for folks who really want to deal with MPEG layer
3 files, possibly including some specifics (like high-efficiency volume
scaling or the crude equalizer).


Alrighty then,

Thomas