Re: [Debconf-video] Advice about a video system
On Tue, Feb 15, 2011 at 11:31:40AM -0600, Carl Karsten wrote:
> PC to run DVswitch: $600 ish. It does not need lots of CPU or ram.
Actually, I disagree with that one. You do want a somewhat modern PC for
the machine that will do the switching. The RAM doesn't need to be
extreme, but since you'll be decoding several streams, scaling them,
possibly combining several of them in a pic-in-pic or fade effect, and
finally re-encoding the stream, it does need quite some CPU power.
On my laptop, which has a 2Ghz Core2 duo, I've experimentally discovered
that you can do about 7 streams if you want fade, or up to nine if you
don't, without performance issues. Granted, most setups won't need as
much, but if you're doing dvsource-alsa, twinpact, two cameras, and a
sponsor stream, you've already got five streams to decode.
> it needs about 130 gig of drive space for a day of recording. it
> needs 1 firewire *bus* (not port) for each video source (2 for 1
> camera, 1 twinpact) - most firewire cards only have one bus. line
> level audio in which will be hooked to the mixer.
Note that these can all be distributed over the network: dvsink (which
stores the recordings, or runs the transcoder for streaming) doesn't
need to run on the machine that runs dvswitch; and dvsource (which grabs
video and audio from firewire) doesn't need to, either.
The biometric identification system at the gates of the CIA headquarters
works because there's a guard with a large gun making sure no one is
trying to fool the system.