[Ffmpeg-devel] mp3onmp4

bond b-o-n-d
Mon Nov 21 00:30:22 CET 2005

> > I've heard that its possible to encapsulate mp3 in mp4. Is there support
> > such a mode in ffmpeg, which I have missed today?

its indeed possible to mux mp3 audio into the .mp4 container (which is not
the same as .mov)

there are two tools existing allowing you to do this 100% spec compliant,
that is mp4box from the gpac project and mp4creator from the mpeg4ip project
yes, ffmpeg can NOT do this correctly

> Such a mode is possible in a few ways. Try simply stuffing MP3 audio in
> the QuickTime container along with ISO MPEG-4 video. In this case, the
> fourcc will be either 'ms' + 0x0055 (CBR) or '.mp3' (VBR). The QT/MP4
> file format also supports general MPEG audio inside the MP4 container.
> This audio can be MP3 as well as AAC (layers 1 and 2 are probably
> supported as well).

people have to differentiate between .mov and .mp4
there are not "few ways" for placing mp3 in mp4, there is only one defined
in the mpeg-4 specs
as already mentioned its done by using "mp4a". not the here mentioned "'ms'
+ 0x0055 (CBR) or '.mp3' (VBR)"

the next thing is that ffmpeg will NOT create a spec compliant .mp4 files
when directstream copying from .avi. i again have to point to my open .mp4
issue list of ffmpeg where all the open problems are listed:

> Does QuickTime Player play it? That's the gold standard as far as QT
> media is concerned.

i hope you are joking? qt is definitely not the gold standard when it comes
to mpeg-4 (and this includes the .mp4 container). qt handles as good as
nothing you can do with .mp4 and this includes mp3 which it doesnt handle in

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