Need help with Iris genlock option (CG3)

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jan-jaap
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Need help with Iris genlock option (CG3)

Unread postby jan-jaap » Mon Mar 03, 2008 1:33 pm

I'm having some troubles to get video (not monitor output, but PAL resolution video) from an Iris CG3 (genlock option). I think I've got a complete set:

* The CG3 card (a 6U VME card that goes into the VME slot of the Personal Iris)
* A short BNC cable to connect the CG3 to the Iris genlock clock BNC
* A DB15 (?) cable to connect the Iris 'genlock option' connector to the CG3
* A short cable to connect the RGB out of the graphics to the CG3
* A new PROM for the GR1 board but my GR1 has a more recent PROM rev. still
* 4 RAM (??) chips in an unopened static bag -- I'm clueless about these.
* And a breakout box with a dozen or so BNC's and a cable to go to the CG3.

Everything is hooked up, the 4D/25 is running IRIX 4.0.5, and I have connected a video camera to the 'vid out' BNC of the breakout box.

The video doesn't synchronize. It looks a bit like a monitor that doesn't sync, so I'm assuming this is a similar problem. I've tried to 'setmon PAL' it (it's the PAL version), followed by stopgfx; startgfx. Something is happening, but the picture doesn't sync. gfxinfo tells me my graphics is still running at 1280x1026_60.

The BOB has component (RGB+sync) video out but I don't have anything to connect it to.

There are two knobs on the BOB marked 'HOR PH' and 'CSC PH', I assume they have something to do with phase control but I can't restore the picture by turning them.

The theory of the CG3 option is that it encodes the RGB out of the GR1 graphics into a composite or component separated video signal, and can genlock either this video or the graphics output (?) of the Iris to an external genlock source. But does it need a genlock source to work at all? Would that explain my lack of sync?

Oh, I've got a Broadcast Video option (BVO) in my PowerSeries 4D/440VGX. This does basically the same, and I've tested it with the same camera. It also adds genlock in/out the the 4D/440, but seems to work fine without an external genlock source.

I'm running out of options. Does anybody have any experience with this thing?
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To accentuate the special identity of the IRIS 4D/70, Silicon Graphics' designers selected a new color palette. The machine's coating blends dark grey, raspberry and beige colors into a pleasing harmony. (IRIS 4D/70 Superworkstation Technical Report)

jdboyd
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Re: Need help with Iris genlock option (CG3)

Unread postby jdboyd » Mon Mar 03, 2008 3:22 pm

jan-jaap wrote:Everything is hooked up, the 4D/25 is running IRIX 4.0.5, and I have connected a video camera to the 'vid out' BNC of the breakout box.


Shouldn't the video camera be hooked to an input rather than an output?

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Re: Need help with Iris genlock option (CG3)

Unread postby jan-jaap » Mon Mar 03, 2008 11:36 pm

jdboyd wrote:Shouldn't the video camera be hooked to an input rather than an output?

No, I'm using the camera as a (tiny) TV screen. Genlock doesn't provide video input btw.
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To accentuate the special identity of the IRIS 4D/70, Silicon Graphics' designers selected a new color palette. The machine's coating blends dark grey, raspberry and beige colors into a pleasing harmony. (IRIS 4D/70 Superworkstation Technical Report)

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Re: Need help with Iris genlock option (CG3)

Unread postby jdboyd » Tue Mar 04, 2008 6:47 am

jan-jaap wrote:
jdboyd wrote:Shouldn't the video camera be hooked to an input rather than an output?

No, I'm using the camera as a (tiny) TV screen. Genlock doesn't provide video input btw.


What does it use for a sync input if not a video signal then?

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Re: Need help with Iris genlock option (CG3)

Unread postby jan-jaap » Tue Mar 04, 2008 8:00 am

jdboyd wrote:What does it use for a sync input if not a video signal then?

I was hoping it was using an internal sync generator?
Here's a fragment from a post on comp.sys.sgi:
they [CG2] are a pain, mainly in that
they don't put out bi-polar NTSC, which results in a grey-level shift
that is quite objectionable, and the internal sync generator is so awful
as to be unusable without a time-base corrector.

The example code in the same posting contains this comment:

Code: Select all

/*
 *  Optional CG2 GENLOCK board is installed.
 *
 *  Mode 2:  Internal sync generator is used.
 *
 *  Note that the stability of the sync generator
 *  on the GENLOCK board is *worse* than the sync
 *  generator on the regular DE3 board.  The GENLOCK
 *  version "twitches" every second or so.
 *
 *  Mode 3:  Output is locked to incoming
 *  NTSC composite video picture
 *  for sync and chroma (on "REM IN" connector).
 *  Color subcarrier is phase and amplitude locked to
 *  incomming color burst.
 *  The blue LSB has no effect on video overlay.
 *
 *  Note that the generated composite NTSC output
 *  (on "VID OUT" connector) is often a problem,
 *  since it has a DC offset of +0.3V to the base
 *  of the sync pulse, while other studio eqiupment
 *  often expects the blanking level to be at
 *  exactly 0.0V, with sync at -0.3V.
 *  In this case, the black levels are ruined.
 *  Also, the inboard encoder chip isn't very good.
 *  Therefore, it is necessary to use an outboard
 *  RS-170 to NTSC encoder to get useful results.
 */

Maybe it defaults to syncing to an external source and I need to tell it explicitly to use internal sync. I guess I'll have to load the compilers and check out the 4Dgifts. Right now I just (from a serial connection) set the resolution to PAL, and ran stopgfx; startgfx so the graphics console is at the login prompt.

AFAIK, CG2 and CG3 are the same, only CG2 is NTSC and CG3 is PAL.
:PI: :Indigo: :Indigo: :Indy: :Indy: :Indy: :Indigo2: :Indigo2: :Indigo2IMP: :Octane: :Octane2: :O2: :O2+: Image :Fuel: :Tezro: :4D70G: :Skywriter: :PWRSeries: :Crimson: :ChallengeL: :Onyx: :O200: :Onyx2: :O3x02L:
To accentuate the special identity of the IRIS 4D/70, Silicon Graphics' designers selected a new color palette. The machine's coating blends dark grey, raspberry and beige colors into a pleasing harmony. (IRIS 4D/70 Superworkstation Technical Report)


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