[linux-elitists] USB knobs and buttons.

Joakim Ziegler joakim@avmaria.com
Thu Jul 31 22:04:41 PDT 2003


On Thu, 2003-07-31 at 17:51, Nick 'Sharkey' Moore wrote:
> On 2003-07-31, Joakim Ziegler wrote:

> > Another fun question to ponder: Are there good, reasonably priced, Linux
> > controllable video matrix switchers out there? JWZ uses one at the DNA
> > Lounge, described at http://www.dnalounge.com/backstage/src/switcher/

> > I'm slightly surprised noone's put this
> > functionality on a PCI card with a breakout box or something, really.

> Go for it!  You'd just need to connect one of those USB interface
> cards up to a 8x4 video crossbar IC, or several.  Mitel used to make one,
> but I can't find it now ... the microship project uses them,
> so maybe you could ask that guy ...

Yeah, I looked at that, but why bother when very nice people such as
Ryan Sheldon at National Control Devices make finished 16x2 video and
8x2 RS-232 controllable audio switchers that sell for 149 dollars? The
problem was that all their stuff was composite, and I really want Y/C,
but when I mailed them, I got a very nice reply; The 8S2S audio 8x2
stereo audio switcher (http://cl.no/aa) can be used for Y/C video, if
you just make adapters for it. Of course, this is video switching in the
most primitive sense, about the same as flicking a mechanical switch, it
doesn't even wait for the vertical blank, but it should work with most
consumer equipment, since it tends to tolerate a lot more crud in the
signal.

I figured that if I wanted to get more serious about switching, the next
step up would be something like the Kramer Electronics VS-4X4YC
(http://www.kramerelectronics.com/indexes/desc.asp?p=VS-4X4YC), which
retails for between 600 and 900 dollars. It's 4x4, does Y/C or
composite, and does switch-on-vblank.

I'll probably end up trying out the NCD 8S2S and seeing if that works
for me, it's just too cheap to ignore. If that's not good enough, I
might splash out for the Kramer box.


> If you really wanted to fix the sync problem, you'd need to come
> up with something Fiendishly Clever, like a set of video FIFOs
> which could adjust frame sync. 

If you want to get serious about sync, it's pretty easy to get a TBC
module to put in front of whatever other devices you use. If you do
that, everything should be perfectly in sync from there on. But those
cost a bit again, "industrial" quality TBCs cost upwards of 800 dollars
for a 4-channel Y/C device, as far as I can see.

-- 
   The Private Joakim Ziegler - Not Speaking For Anyone But Myself
    joakim@avmaria.com - http://www.avmaria.com - rdgzt@Undernet
            http://www.avmaria.com/ - http://www.fix.no/
		






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