Re: [libcvd-members] libcvd cvd/Linux/dvbuffer3.h cvd_src/Linux/dvbu...

[Edward Rosten]

On Tue, 15 Jul 2008, Georg Klein wrote:

> Erm, so it turns out that
>
> 1. the juju stack is buggy as hell, at least with my hardware. As soon as the 
> app does any work besides just grabbing images, it'll lock the capture up. 
> Avoid.

Like changing exposure, etc?

> 2. using libdc1394v2 with the old kernel stack works, but it has strange 
> locking behaviours (as in: a new program will steal the old one's camera), 
> and does not handle program crashes as well as v1 (you have to use a 
> dc1394_reset_bus utility to clean up after it.)

There's a funny thing about firewire. You can grab data without being the 
one to initiate a grab. In principle, you can daisy chain N computers 
together, put  one camera on and they can all get the data. Or does this 
grab stop the original program getting data?

> So for now, using --without-dc1394v2 is probably a good idea. But I'm sure 
> it'll be great in the future. Yeah!

Fair enough. I'm doing a small mod of libCVD, so some options can be 
disabled by default. Fast-7 seems to crash about 20% of GCC compilers and 
takes ages to compile, so I might have it disabled by default. I can do 
the same for dc1394v2 as well.

> PS as of 2.6.26, the uvc-linux v4l2 driver is in the mainline kernel. Woo! We 
> may soon get to the stage where video input works out of the box.

Except that this coincides with a change in API in ffmpeg :-(

Do many devices do UVC? I thought USB webcams were all hand hacked. I 
haven't been following this much recently, though.

-Ed