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Adl  
#1 Posted : Wednesday, June 19, 2019 1:19:10 AM(UTC)
Adl

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Hello,

I use vMix on live events. Inputs are 2 cams in my Magewell Pro Capture Dual SDI Card and PowerPoint presentations via radio link in my Magewell USB Capture Card.
I record internal and use external output with my BMD Intensity Pro Card to provide a 1080p signal to an external DVD recorder. We burn DVDs directly in the event breaks on site and sell them following after the seminar event.
So far no need for speed in the processing of vMix. I know that the HDMI external output has a significant delay (lip sync) but this does not hurt in that setting.

Now, the needs are getting stronger, that I should give my ready mixed signal on a projection. Suddenly, latencies and delays become important.

Normally if I provide a projector with video mix I don't use vMix. Then I prefer a BMD ATEM, with around one frame delay. My cams have 1-2 frames delay and Atem another frame. So I can provide the projector with 2-3 frames delay. Depends on the projector, but usually another 1-2 frames from the projector. But I stay under 5 frames delay all in all. Acceptable for most untrained viewers.

But in these settings where in normally user vMix I don't want to give up on vMix - too many advantages.

If I compare the video delays in vMix. The preview and live window is not that bad. But on the way to the external output with BMD Intensity Pro card there comes a considerable additional delay.
Till now I did not use the Low Latency Capture setting under performance. This should give my another frame on the input side. But what is with the output side?
The BMD Intensity Pro Card is a pretty old card. Can someone provide me with informations if newer BMD cards are faster? Perhaps like the BMD Mini Monitor?

To be honest I don't really like the BMD drivers. They sometimes cause latency problems on some machines and dropped frames. So I would not mind if someone could recommend me a fast card for the external output of another manufacturer.

Does someone use vMix in a live environment and provides a projector? Is this possible with processing speed and delays or do you give me the advice not to try at all and stay with dedicated live mixers?

Thanks,
Adl

EDIT: Just red this article: https://www.vmix.com/kno...e/article.aspx/3/latency
So I think fullscreen over graphics card output would be the way to go and not extern output. Anybody use this setting? delays?
Henny  
#2 Posted : Wednesday, June 19, 2019 4:04:22 AM(UTC)
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I use vmix for live events all the time, use the Fullscreen out function and output from your graphics card for lowest latency
mjgraves  
#3 Posted : Wednesday, June 19, 2019 8:06:08 AM(UTC)
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While there can also be delays internal to how a card itself works, passing the stream around the system is a significant source of delay.

vMix acts on the video using the CPU and/or GPU. The CPU and GPU have the fastest interconnect.

You incur some delay every time the stream traverses the PCIe bus. When an SDI source goes from the capture card to the motherboard & video card, there's some delay.

If it has to go back to the capture card, or another card to be output, that adds more delay.

If it can be output from a second or third port on the GPU, since it's already on the card, so no additional delay to reach its destination.
Adl  
#4 Posted : Thursday, June 20, 2019 7:57:12 AM(UTC)
Adl

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I understand. I have an Intel onboard graphics card with HDMI out and the external Nvidia 1050 Ti graphics card with three ouputs (Displayport, DVI and HDMI). I already activated iGPU so that I can use both graphics cards side by side. I already tested onboard HDMI to my vMix monitor and Nvideo HDMI to simulate output to projector and vise versa. It's much less delay compured to the BMD card for external output. And now I understand why, thanks for the explanation.
Do you think I can reduce the delay even a bit more if I don't spread about two different graphics cards and use instead two outputs on my Nvidia card? Can not test it at the moment, need an adapter first...
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