On Wed, 2004-01-28 at 00:49, Dan Dennedy wrote:
> > The cameras I am using are ADS Technologies Pyro Webcams.
> > They use a firewire interface. The linux boxes are pentium
> > based PCs. The OS is Redhat Linux 9.0 with
> > kernel#2.4.20-28.9. I am connecting 2 cameras per PC.
This setup looks OK.
> > I am using libdc1394-0.9.1 to grab images from the webcams.
Is it a problem for you to update your kernel? If not, update your
kernel to 2.4.24 and update libdc1394 to the latest CVS.
> > With the functions NOT using DMA, it works fine. The only
> > problem is, the frame rate drops to half maximum rate,=20
> > maybe because I am connecting 2 cameras per computer. But
This is normal: the non-DMA technique is much slower.
> > when I use the DMA to grab images, even when I connect 2
> > cameras per computer, they both operate at maximum allowed
> > frame rate simultaneously. But now the problem is, the DMA
> > functions do not always work. They either do not start at
> > all (when I run the code, it stalls) or even if it starts
> > working, after a while, it gives this error:
> > (dc1394_capture.c) VIDEO1394_LISTEN_WAIT_BUFFER ioctl failed!
> > unable to capture a frame
> > The "not starting at all" problem though sometimes does not
> > exist, ie, those computers that do not start at all
> > sometimes do start taking pictures.
> > Do you have any idea what my problem could be and how I can
> > solve it?
Some things to check or try:
1) Do you set the ISO speed and channel correctly? I.e.:
- ISO speed set to 400MBps
- ISO channel set to 1 (camera 1) and 2 (camera 2)
2) The video1394 device should have a major/minor of 171-16 (check this
with 'ls -l /dev/video*')
3) The following modules must be loaded: ieee1394, raw1394, ohci1394 and
video1394 (check this with 'lsmod', as root).
4) How does your program work with only one camera?
5) You can use coriander to check if your cameras can be used with your
configuration. Roughly, if coriander works the problem is in your
program, if it does not work the problem is in your configuration.
_ Damien Douxchamps
(=B0- PhD Student / Research Assistant
//\ Image Processing Group, Telecom Laboratory, UCL, Belgium
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