Questions about video capture/playback
eyal at eyal.emu.id.au
Sun Dec 8 15:36:28 EST 2002
I have this video tuner, and I decided to experiment with the recording
capabilities of the card.
I use xawtv with it and everything works well. I now ran 'streamer' to
capture the video and xine to play it. mplayer had the same distortion
but it could not handle the full resolution (768x576) playback.
The first problem is that the audio comes out distorted (sounds
This does not depend on the volume as set by the mixer, or on the
channel recorded. xawtv is clear, streamer is not.
A second problem was encountered when I attempted to encode the data
mpeg. I do this:
lav2wav +p $show.avi | mp2enc -o $show.mp2 -v 0
lav2yuv +p $show.avi | mpeg2enc -o $show.m2v -v 0 -f 3 -b 2500 -V 500
mplex $show.mp2 $show.m2v -o $show.mpg -v 0 -f 3 -b 500
The source avi for a 1h program is about 7GB, and I found that the *.m2v
file was way too small. Testing it proved that the original avi was
processed only up to the first 2GB. Is my lav2yuv too old (I am on
Debian 3.0)? I suspect that lav2wav has the same problem.
Anyway, the encoding takes a lot of time and uses the full CPU. The
capture itself uses 90% CPU (on my 1.2GHz Athlon) so I will not be able
to capture and compress. I will now look for a good mpeg encoder/decoder
card that likes Linux - any suggestions? Are there TV tuner cards that
already have it, or video cards that have this support?
My capture looks like this ($2 is recording time)
streamer -q -t $2 -s 768x576 -r 25 -o $f.avi -f jpeg -j 86 -F mono16 -b
Eyal Lebedinsky (eyal at eyal.emu.id.au) <http://samba.org/eyal/>
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