Video capture

[Roger Oberholtzer]

On Thu, 3 Oct 2002 19:19:26 -0400
Joel Hammer <Joel at hammershome.com> wrote:

> I think my letter about video capture never made it to the list, so I'll
> try again.
> 
> We are going to get a digital photomicroscope for our pathology lab. I am
> not satisfied with the software demonstrated thus far. Awkward and too
> many steps involved in capturing and saving an image.
> 
> So, is there a linux solution?
> 
> The camera has 3.1 million pixels. The digital camera has a firewire
> connection. What video cards and video capture software are available for
> linux?

If it is firewire, the support is very good. Just be clear when you are
looking for software that you differentiate between digital camera and
digital video. They each have their own standard and thus software. I would
imagine that your device is a camera that provides distinct non-compressed
images.

If it is a digital camera, then check out coriander. It is a general purpose
firewire camera grabber and will even stream it with real media. Or just
simply save it to disk. It is a GUI-type program. It is based on two
libraries that do the dirty work of getting the images. So it is also quite
easy to make your own app. Just be sure to get an OHCI-type firewire card,
as they support DMA for great speed. Also, a video card that supports the X
video extension is good to have (type xvinfo to see if yours does). We use
NVidia's X drivers with their cards and are quite happy.

We have such a setup and it allows us to show live 1280x960 7.5 fps images
while our software is busy doing its other jobs.

If it is digital video, then the very simplest program is dvgrab. It just
grabs video info to a disk. But I suspect yours is not digital video.

> I want to be able to capture, save, and label the image with a single
> click or keystroke.  This scope will be used by physicians, so the
> software has got to be absolutely easy to use and fool proof.

All very doable. And easy. I have a command line program that we use for
testing connectivity that allows basically that. You are welcome to it.
If nothing else, it shows how easy it is to do this sort of thing if the
available tools don't quite meet your needs. In our measurement system, we
obviously had to make a custom solution. But the libraries for accessing
this equipment made it painless.

Also check out http://www.linux1394.org/

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