[mythtv-users] good capture card?

[James Crow]

On Thu, 2008-06-19 at 23:18 +1000, Lindsay Mathieson wrote:
> steve.goodey at bt.com wrote:
> > Apparently there's one with four inputs. :-)
> >   
> 
> What was the thing? One of those security cams that outputs to 4 images 
> on a LCD or something?
> 
> 
> 

That is one of the 4 input bttv cards. Most (all?) bt878 chips can
accept four inputs at the same time. For TV watching you can only use
one because if you try to use more than one you do not get 30 frames a
second. For security camera use 30 frames a second is overkill and
requires way too much storage space. Some video surveillance cards have
4 inputs hooked to one bt878 chip and you can get at most 5 frames/sec
per input. Some cards have 2 inputs per chip for about 12 frames per
second. Some cards have 4 chips and four inputs that you can get 30
frames/sec per input, but these are software encoded cards and they need
lots of cpu power. A recent system I setup has 32 inputs and does motion
detection. It has dual quad core xeon cpus and load hovers between 4 and
5 recording 23 video streams at 5 frames/sec. 

HTH
James