[Libav-user] [Audacity-devel] Requesting help to port Audacity to recent FFmpeg

[Benjamin Drung]

Hi Michael,

Am Mittwoch, den 21.05.2014, 02:16 +0200 schrieb Michael Niedermayer:
> > I like to commit your
> > work to the Audacity SVN so that we have both - support for FFmpeg and
> > Gstreamer.
> 
> that sounds great

I committed your code to the Audacity SVN with your name in
Signed-off-by, because I failed to find a git-am equivalent to preserve
the committer and date. Thanks for your work.

While committing, I made some small indentation adjustments. Audacity
uses 3 spaces for indentation and some of your changes used 4 spaces. I
merged your debug fprintf removal into the respective commit. I also
committed my libav 9 support patch.
 
> > 2) I can't export audio as mp4. Neither as mp4 export, nor as custom
> > FFmpeg export (can't be selected there). FFmpeg has mp4 support enabled:
> > 
> > $ ffmpeg -formats 2>/dev/null | grep mp4
> >  D  mov,mp4,m4a,3gp,3g2,mj2 QuickTime / MOV
> >   E mp4             MP4 (MPEG-4 Part 14)
> 
> hmmm, what do you mean by "mp4" ?
> there are alot of audio codecs that can be stored in mp4, for example
> aac, mp3, vorbis, also there are multiple ways to encode aac, libfaac
> ffmpegs native encoder and a few others ...
> 
> I tried a few things and found a few bugs (which i fixed) but iam
> not convinced i fixed the issue you describe

Sorry. My description was imprecise and incorrectly (m4a instead of
mp4). I was talking about File -> Export Audio... -> "M4A (AAC) Files
(FFmpeg)". When selecting this format, the exported file has 0 bytes
content. Selecting "Custom FFmpeg Export" and then "mp4" format and
"aac" codec, the result will be the same (empty exported file). The same
applies for the wav format with pcm_s16le codec.

-- 
Benjamin Drung
Debian & Ubuntu Developer