LEDWall Compound - Moving 3D Object out of sync between camera output, and Digital Ext

Studio Operators Video Playback SDI Camera Tracking Augmented Reality Unreal

 

I did a test with 2 TVs connected directly into my machine via DisplayPort, and an camera connected via SDI, also directly into my machine. After calibrating the TV/LED Wall, camera zoom, delay, and digital extention delay, I get great results with the footage from the camera, and digital ext being correctly aligned. However, when a scene has a dynamic compontent, like a moving object for example, there is a noticable delay between the LED and the Digital Ext:

https://drive.google.com/file/d/14NvU8Rz0ryvJZyvFXcJM2Sd6hg-NozrB/view?usp=sharing

I tried to compensate by delaying even more the Digital Ext, but then It screws up with my tracking and camera, making everything out of place when moving. I've tried delaying the tracking data, camera, even mask channel, but I just can't find where the problem is located.

Any help with this topic would be greatly appreciated, In the meantime, I'll try to think of something to fiddle with.

   tiagosilvadiretor

 
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Aximmetry
7/29/2021 11:06:34 AM
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Hi,

TV-s usually display their content with a pretty big delay, because of various inbuilt postprocessings.

You can try to set you TV into "game" mode (or what ever marketing term the TV manufacturer decided to use).

This might help.

(in case of a real LED Wall, manufacturers try to make the delay of the LED Wall as minimal as possible)

Best Regards

 
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tiagosilvadiretor
7/29/2021 2:16:53 PM
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The TV we used to test this out already had the game mode turned on. Also, we've had this same problem operating with real LED Walls, that's why we're troubleshooting this problem right now, so we don't end up having to deal with the same problem again. 

 
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tiagosilvadiretor
7/29/2021 3:07:04 PM
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We just made a test with our Blackmagic SmartView 4K monitor as a LED Wall, connected via an 6G SDI Cable (here's the link of the monitor we used: https://www.blackmagicdesign.com/products/smartview4k ).

Not only I had the same result, but I ended up having to reduce the Digital Ext delay due to the video processing being faster than the TV we were using, making my moving objects go way out of sync!

Here's a video with the same delay value as the tests before: https://drive.google.com/file/d/11XTR7VnMWvVCu4_FNX3jcxBB3ZK_CF49/view?usp=sharing

 
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Aximmetry
8/10/2021 4:02:38 PM
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Thanks for the extra info. We are currently investigating this issue.

 
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tiagosilvadiretor
9/1/2021 4:40:53 PM
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Hello,

Just wanted to know If you guys are still investigating this issue, If so, how's the progress?

 
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tiagosilvadiretor
10/13/2021 4:20:13 PM
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Just ran some tests with the LED Wall compound again on 2021.3.2, and the problem still persist. Are you guys even investigating what is going on????

 
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GarfieldS
3/4/2022 4:56:52 PM
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we do have the same problem with multi machine and 3led set, any updates?

 
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Eifert@Aximmetry
4/1/2022 8:44:06 AM
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Hi GarfieldS,

Describing the issue in detail could help us a lot, as you are using probably a more complex setup with multi-machine than the previous posters.

Note that, setting up a Delay in the Digital Extension will sync up the animations. But this delay also delays the placement of the led wall within the Digital Extension. This delay makes the Digital Extension to use images rendered in the past, based on the tracking in the past. That is why the tracking will be off if you set high values for Delay in the Digital Extension:

You should try reducing the round trip of the video in your hardware. That means reducing the delay between your computer's video out to the led wall. And reducing the delay from the camera to your computer.

In Aximmetry, you should try to set in the Edit->Preferences the In to out latency as low as possible without losing the video signal:

Warmest regards,

 
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RhynoProject
7/9/2022 11:47:57 PM
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I don't understand how such an expensive program doesn't get a solution, when I cut from one camera to another the 3d on the LED wall takes a while to work

 
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Eifert@Aximmetry
7/21/2022 3:12:51 PM
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Hi RhynoProject,

Picture Delay is the solution you are looking for: https://aximmetry.com/learn/tutorials/for-studio-operators/using-led-walls-for-virtual-production/#switching-between-cameras

Note that there is always some delay due to the hardware sending out the video signal and the led wall processing it. This is why the Picture Delay will delay the switching between the images of the cameras, while it renders the other camera's position and outputs that to the led wall.

Warmest regards,