Re: [Motion-user] wow, I'm impressed

[Peter M. <pet...@go...>]

2008/5/30 Roman Gaufman <hac...@gm...>:

> > Hello list,
> >
> > I'm using a 4 chip 4 channel bt878 card on a C2D 4400 with 1GB RAM
> recording
> > 25fps@720x576 on all channels. The System runs at 60-70% CPU load while
> > providing 4x 25fps live video on the desktop an 4x 3fps on a web client.
> > Uptime is about 4 month now.
> > I tried using a 8 chip card, but apparently the PCI Bus couldn't handle
> the
> > load, i had to size down to 512x384.
>
> Hmm, really? -- I have an SAA7134 based card here with 8 chips and I
> record at 25fps from all 8 channels at 640x480 with no problems --
> according to the manufacturer I should be able to add another 8
> channel card to make a total of 16 channels (400fps total), but I've
> not tried that yet.
>
>
> Well, i didn't dig deeper into it. Recording at 720x576 worked but i had
distorted images with black lines scattered about. With 512x384 they
vanished. 720 * 576 * 24bit * 25 fps * 8ch = 1.8 GB / sec raw data if my
math is correct, so i figured, i had bandwidth problems with the PCI bus the
most likely bottleneck. I tried b/w palette, but couldn't get it to work. I
used a 8 chip SAA7134 card, which card do you use and what driver settings?
Mine is a cheap no brand, i tried every possible driver for it, but none
detected it correctly although it still seemed to work fine.

As far as I know, both the v4l/v4l2 drivers for bt878 and saa7134 support
only 8 chips (motion also uses 0-7 only), so you might have to mix chips for
16 channels.

regards,
Peter Marquardt