[MPlayer-users] encoding a .3gp file

[Nico Sabbi]

Raphael wrote:

> Nico Sabbi wrote:
>
>> Raphael wrote:
>>
>>> Hi,
>>>
>>> I have been trying to make a .3gp file for my mobile phone.  I want 
>>> to use mencoder instead of ffmpeg but am having a problem with the 
>>> amr audio codecs it seems.
>>>
>>> My experimental command line (without any of the bitrate/fps etc. 
>>> arguments needed eventually) is
>>>
>>> /usr/local/bin/mencoder stream.dump -oac lavc -ovc lavc -lavcopts 
>>> vcodec=h263p:acodec=amr_nb -of lavf -o movie.3gp
>>>
>>> which gives the error
>>>
>>> "
>>> Couldn't find wav tag for specified codec, exit
>>> "
>>
>>
>>
>>
>> this means that you have to specify atag=NNN that you should know or 
>> search in libavcodec
>>
>
> Hi,
>
>
> Could you specify further?  The only thing the man page has to say 
> about atag is
>
> "
>    atag=<value>
>               Use the specified Windows audio format tag (e.g. 
> atag=0x55).
> "
>
> and there appears to be no documentation about atags on the web.


it's the infamous two-cc code used to identify audio in  waveformats :(

>
> Looking in the directory libavcodec of the source doesn't seem to 
> help. Also, it is not clear to me what is going on as .3gp is not a 
> Windows format and nor is amr (or am I wrong?).


there are no os-specific formats

> In case it helps, I have attached below the output of mplayer -v on a 
> working .3gp file I got from somewhere else. This is what I am trying 
> to reproduce. Is the atag hidden in the mplayer output somewhere?
>
> Raphael


there's not two-cc in mov/mp4/3gp, that's why you don't see it. To say 
the truth it seems there's no
assigned (or frequently used) two-cc for AMR, so there doesn't seem to 
be any mention of it in libavcodec.

Can you run

$ ffmpeg -i file.3gp -acodec copy -vcodec copy file.avi

and still play file.avi? what does ffmpeg -i file.avi say?