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How to take movies using cqcam

Requirements

cqcam 0.91 or better:
http://www.cs.duke.edu/~reynolds/cqcam/ The Berkeley parallel MPEG encoder:
ftp://mm-ftp.cs.berkeley.edu/pub/multimedia/mpeg/encode/

Taking the movie

Use the '-m' switch to cqcam. The '-m' switch takes two or three arguments: how long to wait between frames, what to call each frame, and, optionally, how many frames to take. For example, cqcam -m 0.5,foo,100
would take two frames per second, up to 100 frames, and call them foo-1.ppm, foo-2.ppm, and so on up to foo-100.ppm.

All of the other cqcam switches still work. In particular, -32+ will increase your frame rate, and -j will save the frames as JPEGs, which take up a lot less space.

Encoding the movie

To create a movie with all the defaults (24fps, about 50KB/sec), run the 'movify' script that came with cqcam. To turn foo-*.ppm or foo-*.jpg into foo.mpg, run 'movify foo'. Remember to delete the PPM or JPG files when you're done.

If you don't want to use the defaults, create a .param file and run mpeg_encode on it. The MPEG encoder documentation has loads of details on how to do this.

Hints

The Quickcam, with its mediocre frame rate, is best suited to stop-motion or time-lapse movie making. Setting the frame-time to 0 (cqcam -m 0,foo) tells cqcam to take frames as quickly as possible -- still rarely more than 1fps.

Because MPEG encoding is lossy, using 32-bit transfers (cqcam -32+) will improve your frame rate somewhat without degrading output quality much.

By default, cqcam will perform auto-brightness continuously while taking the movie. To disable this, use the '-a-' switch as usual.