problems converting to 3gp

[swedishlf]

Hey guys, I have a Motorola E815 which can play 3gp videos. I have successfully converted certain videos to 3gp using super c in a windows qemu session, but that is very slow for big files. I am attempting to convert using mencoder, mplayer, and ffmpeg in linux which seems to be much faster, but I am having audio problems. If I encode a video without audio it plays flawlessly, but if I encode with the audio the video stutters horribly and is unwatchable. This is the script I'm using (nautilus shell script) to convert the videos:

mencoder $NAUTILUS_SCRIPT_SELECTED_URIS -nosound -ovc lavc -lavcopts vcodec=mpeg4 -vop expand=176:144,scale=176:-2 -o movie.avi -ofps 12.5

mplayer -vo null -ao pcm -af resample=8000,volume=+4db:sc $NAUTILUS_SCRIPT_SELECTED_URIS

ffmpeg -i movie.avi -i audiodump.wav -b 144 -r 12.5 -s qcif -aspect 11:9 -vcodec h263 -ar 8000 -ab 13 -ac 1 -acodec amr_nb -map 0.0 -map 1.0 movie.3gp

rm movie.avi
rm audiodump.wav

If anyone has any tips, I would greatly appreciate it!

[GMaq]

Hello,
You may be interested in WinFF, don't let the name fool you it is a Win/Linux application that is a GUI frontend for ffmpeg. It has presets for 3gp phones, All you need is a recent ffmpeg build with the restricted formats unlocked. I don't know what Linux distro you are using but the repos at www.debian-multimedia.org have a good build that works well. WinFF can be found at www.biggmatt.com

[swedishlf]

Haven't tried out WinFF yet, but I'll give it a look. I managed to bodge together a working system. First I downloaded FFmpeg source from here using the "full checkout" link. Then I downloaded the amr codec source as per the documentaion. Ran ./configure, make, make install on the amr source, then ./configure --enable-libamr-nb , make, make install on the ffmpeg source. Ended up having to add the line /usr/local/lib to the /etc/ld.so.conf file and run ldconfig.

The nautilus shell script I now use is

mencoder $NAUTILUS_SCRIPT_SELECTED_URIS -nosound -ovc lavc -lavcopts vcodec=mpeg4 -vop expand=176:144,scale=176:-2 -o movie.avi -ofps 12.5

mplayer -vo null -ao pcm -af resample=8000,volume=+4db:sc $NAUTILUS_SCRIPT_SELECTED_URIS

ffmpeg -i movie.avi -i audiodump.wav -b 144k -r 12.5 -s qcif -aspect 11:9 -vcodec h263 -ar 8000 -ab 12.2k -ac 1 -acodec libamr_nb -map 0.0 -map 1.0 movie.3gp

rm movie.avi
rm audiodump.wav

It runs much much more quickly than emulated super. The only problem I am now running into is a little bit of audo/video mismatching. Any ideas what might cause this?

[GMaq]

OK,
I don't know what kind of frame rates you can get away with for cell phone video but I find about 90% of A/V sync issues can be avoided by keeping the frame rate the same as your source ie a 25fps PAL clip should be converted at 25fps. The other issue is whether the encoder can detect delays in the audio stream info. I convert DVD's for my iPod with ffmpeg (WinFF) and usually 1 out of 10 will give me sync issues. The lovely nature of variables in software I guess. Try a clip with WinFF and see what it does with the A/V Sync issue would be my suggestion.

[dizzy123]

i have the same problem with trying to convert a avi to 3gp, i cant use a gui because i need to run stuff over my server in asp.

[mats.hogberg]

Take a look at 3GP Converter. I think it "just" a GUI for ffmpeg, and you can "copy" the functionality using ASP/HTML GUI, I'd imagine. I've done some AVI to 3GP conversions with 3GP Converter that have all come out great and fast.

/Mats