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Dual Link Conundrum

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Richard Wirth
Dual Link Conundrum
on Apr 19, 2011 at 8:00:39 pm

I'm posting this both on Sony and Avid's forum as the problem lies somewhere between the two.

We captured a tape from our Sony 5500 into our Avid Nitris DX in RGB 4:4:4 1:1 via dual link. That part went flawlessly.

Now we want to output. I looked for a way to downconvert the output to 4:2:2 but can't find one.

So we decided to output via dual link. When we connected the output of the Nitris DX to the SRW5500 inputs the result goes purple. To verify the connections, I connected the DX Box directly to a BVM230 monitor and it looks great.

I connected the Nitris DX to an AJA 3GM converter to see if we could take a 4:2:2 down convert from it's monitor output but I get the same purple screen.

Anyone have any suggestions?


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Chad Brewer
Re: Dual Link Conundrum
on Apr 19, 2011 at 10:53:34 pm

I will agree with what the Flanders Scientific guy is telling you...I've never used a Nitris before, only FCP and AJA KONA 3 cards for dual link. At least with a KONA 3 card, you have to specifically set it up to enable dual-link output of the card. Otherwise, you will be missing a color channel (0:2:2) to complete the RGB signal and you'll see the purple image you are seeing. Thus, it seems that you are feeding the SRW-5500 4:2:2 while its system is correctly set to 4:4:4.

Does the Avid have some sort of control panel or output settings to either A) enable dual-link out or B) set to 4:4:4 RGB out?

Also, just to verify, exactly what 2 inputs on the SRW-5500 are you patching in to? I'm not saying you have, but I've seen plenty of people incorrectly patch in to the SRW-5500 and thus not get the proper 4:4:4 signal...

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Richard Wirth
Re: Dual Link Conundrum
on Apr 19, 2011 at 11:09:22 pm

I'm getting a good dual link signal from the Nitris DX box into a Sony BVM230 monitor.

But when I connect the same cables to the A & B HD Inputs of the 5500, I get purple.

I get the same purple result when I attached those same cables to the A & B inputs of the AJA 3GM and look at the monitor (1.5G 4:2:2) output.


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Chad Brewer
Re: Dual Link Conundrum
on Apr 19, 2011 at 11:33:50 pm

[Richard Wirth] "I'm getting a good dual link signal from the Nitris DX box into a Sony BVM230 monitor."

I'm assuming the BVM230 has the 2 input adapters running in parallel for dual link?

[Richard Wirth] "But when I connect the same cables to the A & B HD Inputs of the 5500, I get purple."

Now, when you are seeing purple on the SRW-5500, how exactly are you monitoring off the deck?

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Richard Wirth
Re: Dual Link Conundrum
on Apr 19, 2011 at 11:43:30 pm

Yes, the dual link signal is going to two input adapters on the BVM230 configured for dual link.

To monitor the signal from the deck, I'm connected the HDSDI A&B outputs from the 5500 to the same two input adapters on the BVM230.


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Chad Brewer
Re: Dual Link Conundrum
on Apr 19, 2011 at 11:58:48 pm

Regardless of how the image looks on the monitor coming off the deck, do you also have improper image on the SRW-5500's panel display, color wise?

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Richard Wirth
Re: Dual Link Conundrum
on Apr 20, 2011 at 3:18:14 pm

I'm working in 23.98 and don't have an image on the machine's LCD screen.


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Chad Brewer
Re: Dual Link Conundrum
on Apr 20, 2011 at 11:22:28 pm

Hi Richard,

I've never seen an SRW that doesn't have a video preview on the front panel and I don't even see how you can turn it off, regardless of what the system is set to or what the frame rate is. The reason I was asking is because if you see the right color space on the front panel (which will dislay a 4:4:4 image), but not on the output, then you can isolate an output/monitoring problem.

However, it seems something's wrong in the signal path or the input to the deck. The line of questioning I was getting at earlier was to try and determine if one of the inputs on the deck is bad.

Try this, park the Avid sequence on color bars or any frame of the video for that matter. Patch only the first cable of the dual-link signal. Note what you see coming off the deck. Now, add the second cable of the dual-link signal. Is there any difference in the image between having only the first cable patched and having both patched?

My guess is that if you do see a difference in the color when doing this and it's still bad, something is wrong with hardware/cabling/etc. If you don't see a difference when doing this, I believe the SRW-5500 is somehow only getting a 4:2:2 signal.

Have you tried swapping out the cables you are using?
Do you have the ability to simultaneously patch dual link to the deck in EE and then dual out of the deck to the monitor?

You also might want to start checking the inputs on the deck with 4:2:2 signals to see if you have a bad input...

I hope you get it working and don't have a 4:4:4 board malfunction or a dead B input on the deck.

Definitely let us know if you get the problem solved. Hope this helps a bit in "over the internet" troubleshooting which is difficult.

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Richard Wirth
Re: Dual Link Conundrum
on Apr 21, 2011 at 3:12:07 am

Chad,

Many thanks for your considered comments.

I will try the signal tracing approach as soon as I can wrestle the machines away from the operators (everything is tied up doing other 422 projects right now).

But I will let you know what I find.

Thanks, again!


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Chad Brewer
Re: Dual Link Conundrum
on Apr 21, 2011 at 3:32:36 pm

Also try the same "one at a time" patching approach of the 4:4:4 signal straight from the Avid to the monitor to determine if the Avid itself is providing 4:4:4 instead of 4:2:2...

Forgot to add that to my last post...

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Richard Wirth
Re: Dual Link Conundrum
on Apr 21, 2011 at 4:04:41 pm

Yes, I did do that.

And that's where the plot thickens. I get a perfectly good dual link connection with the monitor using the same cables as I used to plug into the 5500 and the 3GM where I get purple.

Thanks again.


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Joseph Owens
Re: Dual Link Conundrum
on Apr 21, 2011 at 6:51:49 pm

Are your monitors "auto-sensing"? That is, do you need to deliberately need to set the system to recognize the dual-link nature of the SDI path, or do they just "switch"?

I do know that on my SR5500, you do need to do a system re-set (full re-boot) to change the settings, and this takes getting into the top secret Area-51 Engineering section with shift-buttons and everything, otherwise the machine will stay stuck in 4:2:2 Single Link. Also, it "crash" powers-down, so DO NOT reset the system with a tape in the transport. It will be eaten.

jPo

You mean "Old Ben"? Ben Kenobi?


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Richard Wirth
Re: Dual Link Conundrum
on Apr 21, 2011 at 7:15:04 pm

The L230 Channel is set for dual link. It auto senses the frame rate and resolution.

Yes, the 5500 does reboot into 4:4:4 which in theory activates the B input unless I'm missing something.


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Chad Brewer
Re: Dual Link Conundrum
on Apr 22, 2011 at 12:29:14 am

Hey Richard,

So, the monitor could be auto sensing and giving you a proper image despite of what it is being fed. As in, you can patch input B on a 4:2:2 signal and be fooled that it is actually 4:4:4. Like I was saying before you need to test these patches one at a time as the first is the 4:2:2 part of the color signal and the second is the 0:2:2 that completes the 4:4:4.

Forget going from the Avid to the monitor at this point. You need to patch from the Avid to the SRW-5500 in 4:4:4 and simultaneously patch the dual link signal from the deck to the monitor. Better yet, look at the output display on the front of the deck, forget the monitor at this point. Once you do this, patch only the first half of the dual link. You should see your familiar purple. Now, patch the second half. If it is still purple then your signal path is 4:2:2.

I don't know anything about Avids, but I do know about 4:4:4 signaling and this specific VTR. I read that not all Avids have 4:4:4 output options....Do you have a way of verifying outside of this one specific monitor that yours does?

Something's not right here. My hunch is that your signal really is 4:2:2.

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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Joseph Owens
Re: Dual Link Conundrum
on Apr 22, 2011 at 2:57:53 pm

[Chad Brewer] "Something's not right here. My hunch is that your signal really is 4:2:2"

Where is the external scope in all this? You know, the one that tells you what is actually going down the cable, rather than eyeballing everything?

jPo

You mean "Old Ben"? Ben Kenobi?


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Richard Wirth
Re: Dual Link Conundrum
on Apr 22, 2011 at 4:39:37 pm

HaHaHaHaHa! HaHaHaHa! Sorry.

Yeah. A 4:4:4 scope would be a big help right now. Unfortunately, this is 4:4:4 on a shoestring. Everything in the facility is still 1.5G.

I have to wait until next budget cycle to get 2nd SDI cards for our Leaders.

The infrastructure hasn't caught up yet, but we've had a couple things come up that are pushing us forward anyway. We're a school. Students do advanced work at outside facilities and when it gets sent back here we have to deal with it. I bought the AJA 3GM mostly for its capability to downconvert to 4:2:2 but this time it (and the 5500) aren't cooperating.


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Richard Wirth
Re: Dual Link Conundrum
on Apr 22, 2011 at 4:27:53 pm

But if the monitor was only auto sensing 4:2:2 from the A input, that would produce a purple screen since there would be no way it could recover the B input's 0:2:2 signal. And what I see is a complete picture on the monitor.

I agree with you that both the 5500 and the AJA 3GM are only "sensing" the 4:2:2 from the A input.

I just can't figure out why there would be a difference between the monitor's signal sensing ability and the tape machine's.


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Richard Wirth
Re: Dual Link Conundrum
on Apr 26, 2011 at 5:52:56 pm

Thanks, Mark.

Yes, that would follow as our 5500 does not have the format converter card.

I'll check on the firmware but the 4:4:4 card(s) were installed by factory authorized service tech. Except for this issue, there have been no other problems.


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Mark Spano
Re: Dual Link Conundrum
on Apr 26, 2011 at 5:32:01 pm

[Chad Brewer] "I've never seen an SRW that doesn't have a video preview on the front panel and I don't even see how you can turn it off, regardless of what the system is set to or what the frame rate is."

Hey Chad - just FYI - if you don't have the format converter board installed, you will not get any video preview on the front panel of an SRW-5500 when in 23.98. That video preview is a standard def, downconverted signal - you'll see that it follows your setting for CNV MD (DC) - letterbox, edge crop, squeeze. No converter board, no video for 23.98.

My only other addition to this thread would be to make sure the deck is up to date firmware-wise. Firmware can be downloaded here. And make sure that 4:4:4 board was installed correctly - it's not just a pop-card-into-slot thing.



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Chad Brewer
Re: Dual Link Conundrum
on Apr 26, 2011 at 11:51:51 pm

[Mark Spano] "Hey Chad - just FYI - if you don't have the format converter board installed, you will not get any video preview on the front panel of an SRW-5500 when in 23.98"

There's Mark on the thread!
I was waiting to see what you thought on this. I almost threw up a post on the thread with your name just to flush you out:)

See what I get for only working with 5500's and 5800's that are rockin' all the optional boards - I get spoiled and can preview everything and don't realize not everyone can...

In the hopes that Richard's B input is not bad, if firmware doesn't work, I'd pop the hood and re-seat that 4:4:4 board. It's always amazed me that with some hardware that never moves and is in non-earthquake prone areas of the globe, sometimes you have to re-seat hardware cards. We had to do it with our Blackmagic Ultrascope yesterday. Why? We may never know.

I think we both know that video ghosts do exist.

Chad Brewer
Senior Broadcast Videotape Operator
TeleVersions, LLC - Chicago


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