Same decklink input on multiple layers issue

I’m having issue playing same Decklink (4K extreme) input on more than one layer of a same channel.
For example…
play 1-1 decklink device 1 (play OK)
play 1-2 decklink device 1 (404 play failed) (could not enable video input)
It works if I play it on second channel and then route that channel to the multiple layers of first channel.
play 2-1 decklink device 1 (play OK)
play 1-1 route://2 (play OK)
play 1-2 route://2 (play OK)

Is this normal behaviour or am I doing something wrong?
Is this causing any extra delay?

CasparCG version is, same behaviour on

Thank you guys in advance.
Best regards,

The second option is the correct way of doing it and yes it will give you a few frames of extra delay. By the way: Why do you need that? What do you want it for? Probably there is a better way to get the same result.

Hi didikunz,
Thanks for your reply.
I’m developing a small vision mixer. PVM, PGM, AUX (dual DVE )
The problem appeared when AUX took over the decklink input so the PGM couldn’t do it.
My idea was to take put AUX on layer1, PVW on layer2 PGM on layer 3.
The MIX,WIPE… effects works with layer3 and layer2.
AUX is on layer 1 and used as a background for dualDVE.
All layers are “volume 0” except layer3 (PGM).

If you have some better idea, please share.

I mentioned before I’m using Extreme 4K. This wouln’t make sence :slight_smile: I’m still waiting for the delivery of Quad 2.


I did not catch that. PVW. PGM and AUX are, on normal vision mixers, the names of outputs. So, your way of naming inputs is not too logical for me. But anyway, have you seem, what you can do with the SWAP command?

You are right…
I use decklink inputs to feed the 3 layers. In this case I use layes (pgm, pvw and Aux) as outputs, as you mentioned.
Layers 5-10 I use for graphics (html) lower3rds….
Swap command I use to swap between PVW and PGM layer. Pure CUT.
Unfortunately with swap I didn’t managed to do dissolve (MIX). Therefore I had to work on layers as outputs.
For MIX I decrease opacity on layer3 to reveal layer2, and then swap the inputs to the 2 layers.

I still not understand, why you want to play the same input on two layers. The moment you have finished fading away one layer with OPACITY to reveal the layer bellow it, you can SWAP the two layers to switch positions. The layer that was on top is now bellow. He sill has opacity 0 but can then be fade up again, without being visible, because the layer, that is on air covers it. This can be repeated over and over again. You only have to make sure, that the layer, that is on air is the topmost of them all and the layer you want to fade to is one bellow. This works in theory for an unlimited amount of layers, in practice you will end but running out of resources at around 6 with a very strong pc.

I would consider using a cheap vision mixer, like the TVS and use a much smaller box for Caspar to add the graphics. Could be cheaper or equally expensive in the end.

I never wants to play same input on two layers. It happens that an input is alredy used by aux (L1) for example. Then it is imposible to use it on another layer (pgm). The input has to be released from aux layer to use it in pgm layer. I doesn’t sound practical.

I know for TVS, we are using it for small projects, I’m doing this mixer just for fun, becouse it is possible :slight_smile:

In fact the mixer is an addon to a graphics plyout.

This is expected behaviour AFAIK.

One frame of delay. You don’t have to have an extra channel. Routing just the layer will work fine, I would probably put the inputs as base layers, then put a black background on a layer above and then route to the different camera’s. Using routes like that will also enable you to do transitions in the future.

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Great idea! All inputs in single channel and covered by black sounds much cleaner. Thanks.
It would also simplify feeding of layers on chanel3 I use for multiviewer.

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