MOGG file support

As Audition is the only open source software (I know) that can read a MOGG file, I was browsing though the code to understand its file format. However I could not find any handling for this file type in the sources. Can anybody give me a hint which source file does the MOGG file header handling and stream extraction?
Thanks in advance,


Mogg files are a variation of the OGG format.
Audacity can open “some” Mogg files using the OGG decoder. The OGG format is specified by (
I’m not aware of any official specification for Mogg files, sometimes they are standard OGG files with just the file extension changed - sometimes not. There’s no guarantee that Audacity will open a Mogg file, it all depends what the file really is.

I have analysed the MOGGs I have, these are not just renamed OGGs, but have special MOGG file headers before 1 - n regular OGG streams follow. No other (OGG aware) player can read these files - but Audacity can! So there must be some “magic” in the Audition source code, that I didn’t find so far. Or does it use any “special” OGG Lib?


Audacity will use libogg (from if it identifies the file as an OGG file, otherwise it will try to import with FFmpeg if FFmpeg is installed.

Yes, you’re right. After a lot of experimenting and code analysis I agree that libogg / libvorbis do a perfect job. I wonder that so few other software, that include libvorbis, can deal with MOGG…