Ice and video

Did a couple of tests of time-lapse video using a web cam last night, one was of a bottle freezing, the other was of ice melting. Both were captured the same way: attached a Logitech Quickcam Pro 4000 to a linux computer, and used vgrabbj to grab a frame every 2 seconds, saving files:

vgrabbj -d /dev/video1 -i vga -o jpg -f freezer.jpg -L 2000000 -E 1 -A "freezer-ani-%s.jpg" -M 65535

Then after all the frames were grabbed, I used mencoder to make a video suitable for youtube:

mencoder -nosound -ffourcc DIVX -o freezer-yt.avi -ovc lavc -vf scale=320:240 -lavcopts vcodec=mpeg4:vbitrate=1000:v4mv:mbd=2:trell:autoaspect -ofps 30 -mf fps=60 mf:///home/jpimble/freezer/freezer-*

The bottle video was captured with the camera inside my closed freezer, along with CF light bulb (plugged in) to provide a light source. I was surprised that both functioned perfectly even though it was cold enough to completely freeze the bottle of water. The bottle video is played back at 240 times normal speed.

The ice melting video is played back at 600 times normal speed, since it is a bit more…boring. I stopped capturing in the morning, I needed the counter space to bake some cookies.

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