[PATCH] Removed double re-muxing of AAC audio (national radio) to M4A

[dinkypumpkin]

On 12/02/2013 22:03, richard wrote:
> On Tue Feb 12 13:01:13 EST 2013 dinkypumpkin wrote:
>
>> It would also be very helpful to know if you get different results
>> with a modern version ffmpeg, either from Jon Davies' PPA
>
> Apologies. The patch wasn't the cause of the problem playing m4a files
> on the Marantz CD6003. The culprit is recent versions of ffmpeg.
>
> A fix to ffmpeg was made sometime ago, but it appears to have regressed
> back. By coincidence, when I recently tested get_iplayer with Precise,
> it too produces m4a files that don't play.
>
> Anyway, in Lucid I inadvertently installed two versions of ffmpeg:
>
> ffmpeg 4:0.5.9-0ubuntu0.10.04.3 (from Ubuntu Lucid repository)
>
> ffmpeg-static git-N-30582-gef28c7b (from Jon Davies PPA - built on Jun 6
> 2011 15:24:53)
>
> Remuxing flv file with:
> ffmpeg -i file.flv -vn -acodec copy -y file.m4a
> creates an m4a file that doesn't play.
>
> But remuxing flv file with:
> ffmpeg-static -i file.flv -vn -acodec copy -y file.m4a
> creates an m4a file that does play.
>
> get_iplayer downloads using ffmpeg-static (from Jons Davies PPA), and so
> I was not having any problems with that. I've now removed the repository
> ffmpeg 4:0.5.9.
>
> Hope this makes sense.

Thanks for running that down.  Here is what I think it means:

1. ffmpeg was forked as libav in early 2011.  Your ffmpeg 0.5.9 (from 
Ubuntu Lucid repository) is derived from code before the fork.

2. Sometime after the fork - but before Jon made his Lucid build of 
ffmpeg-static - the relevant change was made to the original ffmpeg LINE 
(from whence Jon's build is derived), but not to the libav fork. 
Unfortunately, I have no idea what that change was.

3. The libav fork was adopted by Debian and then by Ubuntu in 11.04 
(natty).  The libav fork would be the version you tried in Precise, and 
it apparently still lacks the particular bit of secret sauce you need.

It would seem you'll be OK as long as you stay on Lucid and use Jon's 
PPA.  If or when you want to move to a later version of Ubuntu, you'll 
probably need to procure a build from the original ffmpeg line, not the 
libav fork.  Jon's get_iplayer PPA switched to using the default libav 
version for 12.04+, but there are other PPAs with builds from the 
original ffmpeg line.  There are also some cookbook guides to building 
it yourself on Ubuntu.