Converting files for iTunes

[Arthur Dent]

On Sun, 2011-07-24 at 19:31 +0100, dinkypumpkin wrote:
> On 24/07/2011 18:04, Arthur Dent wrote:
> > I saw a posting from Jon Davies with a script "fixupm4a.sh" which seemed
> > to be just what I am looking for. Unfortunately it seems to rely on
> > mp4tags (which I have found comes with libmp4v2 on Fedora) and
> > mp4creator which is just not available (that I can find) on Fedora.
> 
> That script doesn't do the actual conversion of AAC files.  It was 
> written to deal with hardware that couldn't play the M4A files written 
> by ffmpeg available at the time.  The script works around the problem by 
> forcing a re-optimisation of the file. See Jon's explanation in the 
> message to which the script is attached. I think the problem may have 
> been corrected in ffmpeg shortly after.
> 
> The basic ffmpeg command to convert a file is:
> 
> ffmpeg -i x.aac -vn -acodec copy -absf aac_adtstoasc -y x.m4a
> 
> I believe we established that ffmpeg from the 0.6 branch produces files 
> that don't work with iTunes.  If that's what you have, you'll probably 
> need to find a more recent version.  The latest release version (0.8) 
> works OK.
> 
> BTW, if it should prove necessary, the mp4file utility that is part of 
> the mp4v2 distribution can replace mp4creator, at least for optimisation 
> purposes.  I'm not a Fedoran, so I'm not sure which RPM you would find 
> it lurking in.

Well Thank You Dinky,

Helpful as ever...

So... This has been a voyage of adventure...

The current Fedora14 version of ffmpeg is ffmpeg-0.6.3-1.fc14.i686 and
the "testing" repository has nothing more recent. Even Fedora15 only has
ffmpeg-0.7-0.3.20110612git.fc15.i686.rpm.

I am not afraid of installing from source, but I generally prefer to use
the Fedora packages where possible. So I fired up a virtual machine copy
of Linux Mint that I happened to have installed and installed ffmpeg 0.8
on that. The .aac files in question happen to be on a Samba share, but I
had a long and boring wrestle with permissions etc in trying to get this
to mount in Mint - but eventually managed to run the command you
recommend above. It worked!

Because I only have 2Mb of RAM in this machine I can't run 2 virtual
Machines at the same time so I had to close Mint and run my WinXp VM and
load iTunes (This is now the only reason I ever run Windows). The test
file I converted loaded just fine.

While I was in Windows I thought i would look at installing MP4Box as
suggested by Catalin Rafael Coman later in this thread (thanks Catalin!)
That was a battle too... However, with it working I found that although
MP4Box converts the file(s) OK, it loses the tag information.

So. Back to Mint, and write a short script to batch convert all the .aac
files and now I'm done!

Thanks again for your help everyone!

Mark

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