Automatic conversion of aac to m4a

[dinkypumpkin]

Good point. I built ffmpeg with today's HEAD, but still no luck remuxing with (or without) aac_adtstoasc filter.  Then again, the problem could well be with some peculiarity of the generated container.  I extracted audio tracks with ffmpeg from a random selection of (non-iPlayer) videos having AAC audio, and some of them also produced m4a files unusable in iTunes, so some more spelunking is in order.

Question to Shevek and Nick: you both say you can import your m4a files into iTunes, but: a) are the durations shown correctly? b) do the files play properly?  Sorry to belabour the point, but if the answers are "yes" and "yes", then I can cheerfully give up and just blame gremlins instead. 

If this turns out to be a problem limited to Mac iTunes (or perhaps just my machine), so be it.  If mp4box isn't a generally acceptable solution, I would suggest adding a programme option and associated logic that could force transcoding for cases where ffmpeg remuxing won't work.   Of course, a user might also have a ffmpeg build without libmp3lame or libfaac, but there's not much you can do in that case.

On 14 Mar 2011, at 15:33, Shevek wrote:

> I think it may be your ffmpeg version - I am using one of the recent builds from the new git repository...
> 
> Sent from my iPhone
> 
> On 14 Mar 2011, at 13:37, dinkypumpkin <dinkypumpkin at gmail.com> wrote:
> 
>> FWIW, using ffmpeg with "-absf aac_adtstoasc" doesn't work in my environment (OSX + iTunes + 5th gen iPod + ffmpeg v0.6.1).  The resulting m4a file will import into iTunes, but it won't play (not on iPod either), and the duration shown is completely