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ayo  
#1 Posted : Sunday, June 21, 2020 3:10:19 AM(UTC)
ayo

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Hello!

I am having a latency problem connecting a DJ booth to my focusrite 2i2 usb sound card. Seems that vmix is setting ASIO buffer size to something weird as soundcard driver shows it as *880* with asterisks, when normal buffer presets are without that. I see no option to set buffer size in input settings at vmix, so I changed the buffer size in card settings panel.

This has been tested in a new empty project with only one audio input with the soundcard.

I made a video showing this and comparing with FL Studio where buffer is handled without asterisks and staying in sync without latency sync problems.


I also attach screenshots of stats and render time.
https://imgur.com/a/BiHNuR8


Anyone has had this problem and found solution?
Thanks for your time reading!!
Vince Beck  
#2 Posted : Sunday, June 21, 2020 4:28:29 AM(UTC)
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It’s out of sync because you are monitoring after VMix processing. The delay is proportional to the render time you see at the bottom of VMix’s screen.
The more inputs you add, the more delay you will see. Yes, the buffer will play a role, but it’s normal. Even without it, you’ll have a 3ms delay at the very minimum. We use the same Focurite units and leave them at their 960 default. The lower, the more chances you’ll have dropouts..
ayo  
#3 Posted : Sunday, June 21, 2020 5:49:36 AM(UTC)
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Originally Posted by: Vince Beck Go to Quoted Post
It’s out of sync because you are monitoring after VMix processing. The delay is proportional to the render time you see at the bottom of VMix’s screen.
The more inputs you add, the more delay you will see. Yes, the buffer will play a role, but it’s normal. Even without it, you’ll have a 3ms delay at the very minimum. We use the same Focurite units and leave them at their 960 default. The lower, the more chances you’ll have dropouts..


Hello thanks for replying.

I maybe explained myself bad. With out of sync I wanted to say "lot of latency" due to the buffer being so high. I used for the example 256 but I use to be at 512 when making music, thats around 12ms. The video explains the real latency between the source and the input is more than 500ms, that is a very lot.

Dont know if you could check screenshots, vmix render time is 0ms.
Vince Beck  
#4 Posted : Sunday, June 21, 2020 6:14:13 AM(UTC)
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Got it. So what about your sample rates, do they match all down the line?

Do you have a world click or are you set to internal.

You could also try removing the Scarlett software altogether and see if it improves.
stefan svanstrom  
#5 Posted : Sunday, June 21, 2020 7:57:22 AM(UTC)
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Same problem with umc 1820 card
Vmix defaults buffer size to 1020
, crazy latency when monitoring with vst plugins.

Hope the fix this
admin  
#6 Posted : Sunday, June 21, 2020 4:38:30 PM(UTC)
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Hi,

The buffer vMix selects is high by design, as any time video is processed on a computer, buffers need to be larger in order
to prevent dropouts, pops and other audio artefacts.

That said, even the highest ASIO buffer vMix selects is 20ms, so not a big delay.
Additional vMix also delays the audio sync better with video, but again this is usually under 80ms all things considered.

So if you are hearing a slight delay in the audio that is all perfectly normal and by design.
A large delay of half a second or more will be due to an issue somewhere else, as vMix does not have any buffers that high.

Regards,

Martin
vMix
ayo  
#7 Posted : Sunday, June 21, 2020 11:14:19 PM(UTC)
ayo

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Originally Posted by: admin Go to Quoted Post
Hi,
That said, even the highest ASIO buffer vMix selects is 20ms, so not a big delay.
Additional vMix also delays the audio sync better with video, but again this is usually under 80ms all things considered.

I am aware of low latency can cause pops and I set it with caution in my tools. In the project I am doing now I went crazy monitoring the live bc of this delay, so I thought on digging it and looking for an improvement was good idea :-)


I made another test to try to find out the origin of this, with 880 samples in FL (the one used by vmix = 20ms), default is double buffer input/output in this app... latency heard is lower than vMix. Using triple buffer the latency is more noticeable but not as much as in vMix... So I guess vMix may be doing more than 2xbuffer input and 3xbuffer output? As is the far I can go in FL and its less latency.

This screenshot explains well the total latency based on amount of samples and number of buffers. So selecting 880 samples equal to 20ms is not 20ms of sound latency, it multiplies with the amount of input and output buffers.
https://imgur.com/a/yB5oFLo

Having a good pc and soundcard, could be possible to be able to config ASIO params in vmix? Like we can do with good GPUs in advanced setings, and like we can do in every music soft with asio support... Being able to select buffer size and some info in the amount of buffers used could bring some light in this internal sound latency input->output, so we know the real audio latency with that config.


TL;DR; Adding ASIO settings to advanced settings in Audio panel would be great :-)


Many thanks for reading!
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