[MEncoder-users] output to 3gp with amr_nb

[Brendan Schwartz]

Hi David,

I realize the man pages say abitrate should be provided in kbps, but
providing a bitrate in bits/s seems to work for me in this case:

This command:

.\mencoder  -oac lavc -ovc lavc -lavcopts
vcodec=h263p:vbitrate=10:acodec=libamr_nb:abitrate=10200 -of lavf -vf
scale=160:120 -srate 8000 -af lavcresample=8000,channels=1  um.mov -o
um-menc.3gp

Yields this:

Video stream:  251.612 kbit/s  (31451 B/s)  size: 944488 bytes  30.030 secs
720 frames
Audio stream:   10.800 kbit/s  (1350 B/s)  size: 40500 bytes  30.000 secs

Hope this helps,
Brendan

On 9/10/07, David Wadler <dwadler at gmail.com> wrote:
>
> I'm having some difficulty generating a 3gp file with amr_nb audio.  From
> what I understand, 3gp/mp4 muxing has progressed a bit with mencoder,and
> it
> seems that once I figure out the audio piece, I'll be able to generate a
> valid file.  (Please correct me if I'm wrong about this. My plan is to use
> lavf.)
>
> Anyway, a problem similar to the one that I'm encountering was raised a
> few
> months ago and apparently solved:
> http://lists.mplayerhq.hu/pipermail/mencoder-users/2007-July/006490.html
>
> However, this doesn't seem to work.  The latest build of mencoder has
> slightly different syntax -- libamd_nb instead of amr_nb -- which I've
> corrected.  I am always gettings errors like this:
> [libamr_nb @ 00C97EA0]bitrate not supported: use one of 4.75k, 5.15k, 5.9k
> ,
> 6.7k, 7.4k, 7.95k, 10.2k or 12.2k
> Couldn't open codec libamr_nb, br=8
>
> Here is an example command line:
> .\mencoder  -oac lavc -ovc lavc -lavcopts
> vcodec=h263p:vbitrate=10:acodec=libamr_nb:abitrate=10 -of lavf -vf
> scale=160:120 -srate 8000 -af lavcresample=8000,channels=1  um.mov -o
> um-menc.3gp
>
> I've tried many values for the audio bitrate, but with no luck.  I can't
> pass in one of the recommended values as the "k" syntax for 1000s and the
> decimal throw it off.  (Mencoder expects an integer.)  For what it's
> worth,
> I'm working on Windows and Linux.
>
> Thanks,
> David
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>



-- 
Brendan Schwartz
Tropist Media, LLC
914 420 6927