Workaround for broken(?) m4a files from ffmpeg, was Re: [PATCH] Output AAC as M4A for iTunes with metadata tags

[richard]

On Fri Apr 15 bat guano wrote:

>> Simon wrote:
>>
>> I think ffmpeg is the right place to handle this. When ffmpeg runs
>> (using -acodec copy), it displays a status line of the form
>> size= 33270kB time=821.71 bitrate= 331.7kbits/s
>> where these values are updated every second or so. So ffmpeg does
>> know the average bit rate, but it doesn't store it in the m4a file.

>
> I also don't think it's a problem caused by streamed files from 
> RTMPDump.
>
> And it's not just '-acodec copy' that gives no avgBitrate.
> FFmpeg doesn't seem to set the avgBitrate when converting other files
> to m4a.
> Using commands like this:-
> ffmpeg -i foo -acodec libfaac foo.m4a
>
> Other encoders, such as faac and neroAacEnc, seem to set the 
> avgBitrate OK though.

Success at last! Posted this problem to the ffmpeg mailing list:

http://ffmpeg.org/pipermail/ffmpeg-user/2011-April/000374.html

and it has now been fixed in the latest git:

http://git.videolan.org/?p=ffmpeg.git;a=commit;h=0ba8485666f532f2dbab716f74e1be1189102c89

The tests I've done so far are positive. I can now play m4a files in the
Marantz without the script to fix up the average bit rate.

Thanks to all who have helped with this.