Resolume Forum

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.

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.

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

Thanks!

I'd do a single GPU output +datapath fx4 (or Quadro) and use SDI converters.

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.

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)

Arvol wrote: Mon Jul 18, 2022 17:58 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.

AJA is extremely backordered, but I was able to get my hands on a AJA Kona which is also Resolume certified. Still seeing noticeable tearing. Any thoughts?

You are getting tearing because you have 2 inputs on a single canvas and the 2 inputs that are driven into those 2 separate processors are not sharing the same clock source (You can genlock the processors but the input from the source isn't locked).
You need an output device that has a shared clock across all of it's outputs. A Quadro card has this and the Corvid line from AJA has this. I can't comment on Kona as I know nothing about it. BUT, if your outputs are not sync'd (sharing the same clock) you will get tearing, regardless of the brand.

Just to close the loop on this, after a long delay I was able to replace the Decklink Duo cards with a single Decklink 4k, and to no surprise this solved the tearing issue. However, to get it them to two different video processors was a bit of a hack but it works -- basically taking a 4k HDMI to SDI demuxer (outputs 4x SDI-3G HD) and then sending the respective quadrants to the correct video wall processor. Next on the list will be to get a single processor that can simply take the 4k input natively without having to do this demuxing bit.

If your LED is running Nova, grab a Nova H2 fully loaded for under $10k and you should be set.