Decklink Video Tearing

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jolson
Met Resolume in a bar the other day
Posts: 9
Joined: Sun Jun 19, 2022 17:33

Decklink Video Tearing

Post by jolson »

Our setup is as follows:
  • Video wall (3840 x 1080) via two controllers running at standard 1080 resolution, split into a left and right half
  • Resolume (composition 3840x1080). Advanced output to 2 screens - SDI outputs on a BMD Decklink Duo card (latest drivers). Also tried outputting across two different Decklink duo cards with similar results.
  • Genlock from an external source, verified genlock using Blackmagic Desktop tool.
  • Output goes into two LED wall controllers running 1080.
Visible tearing across the left/right content. Tested with both mp4(h264) video content, as well as Resolume generated "Line Scape" content. Sometimes the left half of the screen is a frame head, sometimes a frame behind, and sometimes in perfect sync. Most noticeable with "strobing" content (high contrast single frame content).

Any thoughts would be appreciated.

Zoltán
Team Resolume
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Location: Székesfehérvár, Hungary

Re: Decklink Video Tearing

Post by Zoltán »

Decklink outputs are not guaranteed to be in sync.
Resolume passes the texture to the BMD drivers, and then it's up to the driver to display it.
If it's a consistent delay, try adding a little bit of delay to the BMD screens in the Advanced output.
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jolson
Met Resolume in a bar the other day
Posts: 9
Joined: Sun Jun 19, 2022 17:33

Re: Decklink Video Tearing

Post by jolson »

The delay is inconsistent. What SDI output device would provide better sync for edge blending.

Thanks!

Zoltán
Team Resolume
Posts: 6029
Joined: Thu Jan 09, 2014 13:08
Location: Székesfehérvár, Hungary

Re: Decklink Video Tearing

Post by Zoltán »

I'd do a single GPU output +datapath fx4 (or Quadro) and use SDI converters.
Software developer, Sound Engineer,
Control Your show with ”Enter” - multiple Resolume servers at once - SMPTE/MTC column launch
try for free: http://programs.palffyzoltan.hu
VJ footage: https://goo.gl/58oHy7

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Arvol
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Joined: Thu Jun 18, 2015 17:36
Location: Oklahoma, USA

Re: Decklink Video Tearing

Post by Arvol »

BMD is pure rubbish. IF you get the right magical sequence of driver installers to get the cards working, they do not share a clock and you WILL get tearing. Look into an AJA Corvid line card.

jolson
Met Resolume in a bar the other day
Posts: 9
Joined: Sun Jun 19, 2022 17:33

Re: Decklink Video Tearing

Post by jolson »

Upgraded to a AJA Kona 4 (cannot find a Corvid anywhere). Definately seen an improvement, but still experience tearing. Using both internal and external reference (tri-level for 1080i59.94)

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