Webcam recording and mencoder

It is really hard to find proper arguments of mencoder to record not only image, but also sound. Here is my solution. Forcechan=2 is a key.


mencoder tv:// -tv \
driver=v4l:device=/dev/video0:width=320:height=240:adevice=/dev/dsp:forceaudio:forcechan=2\
-ofps 15 -oac mp3lame -lameopts cbr:br=32 -ovc lavc -lavcopts \
vbitrate=92 -o ./encoded.avi


This code works on Linux Ubuntu Feisty Fawn 7.04 with Linux4Video v1 with sound from SoundBlaster Live! with ALSA (on /dev/dsp) with standard recording settings in ALSA mixer (Mic is capturing). ~/.mplayer/mencoder.conf is empty. Kernel module is gspca compiled on my own from the freshest source and copied into directory of original Ubuntu's gspca.ko (/lib/modules/2.6.22-14-generic/ubuntu/media/gspcav1/gspca.ko)
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You can change framerate up to 25, video bitrate to 800 and sound bitrate to 128 or greater to get excellent quality.
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VLC is quite good too, but only for network streaming. Recording to local file causes lack of audio-video synchronisation.
According to VLC manual you can run it from command line as follow:


vlc v4l:// :v4l-vdev="/dev/video0" :v4l-adev="/dev/dsp" \ :v4l-norm=3 :v4l-frequency=-1 --sout \ '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:standard{access=http,mux=ogg,dst=127.0.0.1:8080}'


where all v4l are video and audio sources and sout is output stream. transcoding is definition how to change stream's encoding from source's format to desired, chosen by you.
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Much more options on VLC site.

Update:
Leave VLC and use ffmpeg :-)

For MPEG-2 clips type:

mencoder tv:// -tv \
driver=v4l:device=/dev/video0:width=320:height=240:adevice=/dev/dsp:forceaudio:forcechan=2 \
-of mpeg -ofps 15 -oac mp3lame -lameopts cbr:br=64 -ovc lavc \
-lavcopts vcodec=mpeg2video:vbitrate=512:aspect=320/240 -o ./encoded.mpeg


-of sets output format, default AVI.

To set limited recording time add to the command -frames xxx, where xxx is number of seconds x fps (15 in this case): -frames 900 for one minute clip.