I am trying to use this nifty VGA frame grabber. It's cool that they are at
least acknowledging Linux, even if it is similar to nvidia's support.
Right in the README is an example using transcode - that's kinda cool.
http://www.epiphan.com/downloads/index.php
Looking at the example, I gotta ask how sane it is.
for reference, here are the man page descriptions:
==========
transcode -x v4l,null --use_rgb -i /dev/video -f 3 -g 1600x1200 -y raw,null -z
-r 2 -f 10 -o test.avi
-x v4l,null Video4Linux, no audio.
--use_rgb ...use this option if you're really sure or you want to use a module
that doesn't support YUV.
-i /dev/video input dev
-f 3 is 25fps
-g 1600x1200 video stream frame size [720x576].
-y raw,null Can write uncompressed streams to an AVI file as well as
raw mpeg2 files in pass-through mode.
Supported processing formats: audio - RAW (pass-through)
PCM AC3, video - RAW (pass-through) RGB YUV DV YUV422
-z flip video frame upside down [off].
-r 2 reduce video height/width by n[,m] [off]. Example: -r 2 will
rescale the framesize of a 720x576 file to 360x288.
-f 10 is 5 fps
-o test.avi output file.
==========
I got a few questions...
Why --use_rgb ? (guessing the answer is: device dependent, ask the
manufacture.)
Do I need to specify a fps and resolution, or can transcode detect it?
-f 3 -f 10 Why are there 2?
-z Why doesn't their driver do that?
-y raw - Is that pass through, or does it decompress the mpeg into a hard drive
eating machine? I want to minimize lossy compression until it is edited, but I
will be recording 8 hours at a shot. (maybe only 4, then swap HD's)
-r 2 I don't want to reduce anything. I can just take that out, right?
(wondering why they added parameters that are counter productive.)
-o test.avi If the stream is mpeg, shouldn't I name the file .mpeg?
And just for added noise, here are the mplayer examples:
mplayer -tv driver=v4l:outfmt=rgb24 -flip tv://
mencoder \
-oac lavc \
-ovc lavc \
-lavcopts vcodec=mpeg4:keyint=100:vbitrate=8000:vhq \
-noaspect -flip \
-o test.avi \
-tv noaudio:driver=v4l:outfmt=bgr24:device=/dev/video0 \
tv://
Thanks,
Carl K
