A/V Data Collection Using Linux?

Simon D. Levy asks: "I am consulting in a biology lab that collects data on fruit-fly mating behavior, and we would like to migrate our data collection to a Linux box. Our primary concern is being able to digitize incoming audio signals (at 8kHz sampling rate), but we would also ideally like to be able to monitor the flies' behavior using a digital camera connected directly to the computer. Crucially, we need to be able to isolate the audio component of the signal, as well as having access to an API (C/C++ would be nice) that allowed us to start and stop the recording. Any experience that anyone has had with this sort of problem would be much appreciated. We haven't bought anything yet, and are looking to build this system (CPU, video camera, A/D cards) from the bottom up. Thanks!"

Comments

components

[joekool]

well, two basic parts: hardware and software
first of the hardware is pretty independant of the os, just pick the highest quality capture card you can afford that is supported in linux, add a reasonable camera, sound card, and a nice modern machine of any kind. I use a bttv card, which works well for me, but of course it depends on your exact needs, and the camera that you hook up to it. As to software:
SDL, mostly used for game programming, but has some of the capabilites needed for capturing, sound recording, etc.
v4l the basic component of all video type stuff under linux-you can see the list of crap it supports there, but it doesn't really have facilities for actually capturing to something like mpeg.
avifile everything you want in a capture API, will let you output to all kinds of formats.
mplayer I have heard that they support capturing now, but haven't used them for that, but is what you will be using for playing back the files you capture.

My recommendation would be to use the VCR project, and one of these for audio. VCR uses avifile to record the video in your chosen format, and will record the audio also, but if you want seperate files for audio and video, it is simplest just to use the mic in with another program.

Let me know if you have problems--it's remarakably similar to what is already done to record television programming, with higher quality requirements, so you should be able to take advantage of all the PVR projects out there.
Or you can let me do it-send me the requirements, 1500$, and I'll send the box back a week later
;-}