Decklink latency

and all the interaction

Moderator: Moderator Group

Decklink latency

Postby madido1 » Mon Oct 14, 2013 5:07 pm

Hello,
we have 3 PB players (latest build), with 2 decklink duo and 1 decklink quad installed.
SDI input is working, but with a lot of latency (not mesaured but from 12 to 15 frames).
We are on Windows 7 64bit SP1 and we tried 9.8 and 9.7 decklink drivers.
I've read on other posts that with decklink is possible to obtain much lower latencies...
Is there a specific version of the drivers we have to use (I know that some versions are far from bug free...)?

Thank you

Stefano Sarzi
madido1
 
Posts: 3
Joined: Sat May 08, 2010 9:33 pm

Re: Decklink latency

Postby JustynR » Tue Oct 15, 2013 3:16 am

I have tested at 2 frames on both the decklink duo and the quad.


This is testing with a professional SDI monitor directly before the input, and a professional DVI monitor directly on the output of the Player.

We say that our Player has 2 frames of latency - this does not include 1 frame for the camera (all of them have it...) 1-2 frames for the switcher; 1-2 frames for the scaler (image pro)... and then on the output side 1-2 frames for a consumer monitor; 1-4 frames for the projector and so on.

What is your processing path like? Would this explain it?
Justyn Roy
Field Application Specialist
Christie Digital
Toronto Ontario Canada
JustynR
 
Posts: 555
Joined: Wed Mar 25, 2009 1:33 am
Location: Toronto, Canada

Re: Decklink latency

Postby madido1 » Tue Oct 15, 2013 8:27 am

I'm comparing decklink based players with a coolux server with propietary SDI board on the same video chain and the difference is a lot. Even considering better latencies with coolux SDI, I would expect 1-2 frame of difference with decklink, but now is something closer to 10...
Which driver are you using with decklink?
Thank you
Stefano
madido1
 
Posts: 3
Joined: Sat May 08, 2010 9:33 pm

Re: Decklink latency

Postby JustynR » Wed Oct 16, 2013 1:25 am

The latest one...

As well the latest PB.

One thing that we did notice was that you can usually the lower the latency little bit if you feed the capture card Genlock or the same reference you are sending your switcher / camera(s).

If you start the card before you have sync plugged in.. you've got to re-start PB (or reboot... I just rebooted...) for the card to lock to the sync. I believe this got us 1 or 2 frames faster in our tests.


Also, use the Black magic card directly, NOT the WDM input... the WDM is (from what I've read) made for compatibility and not for speed - it even says that it will have more latency in the manual or in the initial release notes when that feature came out (I don't remember which).

Hope that helps,
Justyn Roy
Field Application Specialist
Christie Digital
Toronto Ontario Canada
JustynR
 
Posts: 555
Joined: Wed Mar 25, 2009 1:33 am
Location: Toronto, Canada

Re: Decklink latency

Postby madido1 » Fri Nov 08, 2013 2:47 pm

Hey Justyn,
thank you for your suggestions.
Finally the tour is over and I can do some test.
In fact the latency is not bas at all with all the necessary tweaks (I think I have something like 2-3 frames now).

Another question; If I use Player as master without a Manager I cannot setup the resolution for the decklink.
If I run PB as client and press the Live input settings it says that the resource is not used in any project and I cannot do anything.
If I use the WDM driver I can change the resolution in Blackmagic control panel.

Any suggestion?

Thank you

Stefano
madido1
 
Posts: 3
Joined: Sat May 08, 2010 9:33 pm

Re: Decklink latency

Postby JustynR » Fri Nov 08, 2013 4:00 pm

To change the resolution of the card when in Master - you've got to add it to your project - click on that input - go to the inspector.
In the inspector, click on the actual card (in the window in the inspector) and click configure.
This will bring up the same window.

The reason for having to click the actual card is because you can attach many inputs from different machines to the same resource. That way if you want to apply the input to several Servers or Players, you don't have to select the correct input for each one - you can select layer 1 on each Client for example and click on "input 1" and if everything has been set up correctly, input 1 will go to all of their respective Client. This also holds true for Virtual Machines.


I hope this helps,
Justyn Roy
Field Application Specialist
Christie Digital
Toronto Ontario Canada
JustynR
 
Posts: 555
Joined: Wed Mar 25, 2009 1:33 am
Location: Toronto, Canada

Re: Decklink latency

Postby RTuinte » Mon Jul 28, 2014 12:49 pm

Justin,

I'm wondering which model/brand professional SDI/DVI monitors do you use for latency testing?

Rogier
RTuinte
 
Posts: 17
Joined: Mon Jul 12, 2010 10:32 pm

Re: Decklink latency

Postby JustynR » Mon Jul 28, 2014 2:49 pm

For these tests I was using a small broadcast monitor: http://www.tvlogic.ca/product/product.php?model=LVM-074W
And I was using a 14k Christie Projector: http://www.christiedigital.com/en-us/business/products/projectors/3-chip-dlp/m-series/Pages/Roadster-HD14K-M-3-chip-dlp-projector.aspx

Both of these have SDI cards built in and don't need conversion or scaling.

Cheers,
Justyn Roy
Field Application Specialist
Christie Digital
Toronto Ontario Canada
JustynR
 
Posts: 555
Joined: Wed Mar 25, 2009 1:33 am
Location: Toronto, Canada


Return to 3rd Party Hardware & Software Components

Who is online

Users browsing this forum: No registered users and 3 guests