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castfeeder  
#1 Posted : Sunday, March 19, 2017 5:57:02 PM(UTC)
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Would vMix call be able to work with green screen? What I'm thinking is I bring in the call where the remote 'guest' has a green screen behind and I then add the green screen 'content'. My aim would be to enable this 'guest' to be the show host (bringing in other guests) and I would do the switching remotely. Possible?
sinc747  
#2 Posted : Sunday, March 19, 2017 7:00:07 PM(UTC)
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Yes, indeedy.

- Tom
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castfeeder on 3/20/2017(UTC)
corporatejames  
#3 Posted : Sunday, March 19, 2017 7:16:00 PM(UTC)
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Have the guest on the green screen at their location and then use Vmix at your end to create the chroma key as you would normally if doing it locally.
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castfeeder on 3/20/2017(UTC)
DWAM  
#4 Posted : Monday, March 20, 2017 10:10:52 AM(UTC)
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Nothing prevents you from getting a vMixCall on green screen in vMix. However you are very unlikely to get good results when doing the chroma keying due to the extreme compression ratio on vMixCalls.

Proper chroma keying requires the least compression and the better subsampling as possible. For example, even for post-production (e.g. not streamed workflow), you always get better results with a 4:2:2 signal than with the same shot recorded in H.264. Best is to use uncompressed shots at 4:4:4 subsampling. Expecting chroma keying to work over a streaming signal is a dream.

If you want remote guests on a virtual background I think the only solution that will give good results is to produce the chroma keying on the remote's end with vMix or another solution and then to use Vmix to vMix Call with the background already integrated.

Guillaume
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mjgraves on 3/20/2017(UTC), castfeeder on 3/20/2017(UTC)
mjgraves  
#5 Posted : Monday, March 20, 2017 12:38:04 PM(UTC)
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DWAM wrote:
Nothing prevents you from getting a vMixCall on green screen in vMix. However you are very unlikely to get good results when doing the chroma keying due to the extreme compression ratio on vMixCalls.

Proper chroma keying requires the least compression and the better subsampling as possible. For example, even for post-production (e.g. not streamed workflow), you always get better results with a 4:2:2 signal than with the same shot recorded in H.264. Best is to use uncompressed shots at 4:4:4 subsampling. Expecting chroma keying to work over a streaming signal is a dream.

If you want remote guests on a virtual background I think the only solution that will give good results is to produce the chroma keying on the remote's end with vMix or another solution and then to use Vmix to vMix Call with the background already integrated.

Guillaume


This is great info and often missed. To take something of a tangent, improved sub-sampling is also the reason that you get better 1080p video by down-sampling a 4K source. Even if the 4K does not start out as 4:4:4 or even 4:2:2.

This along may be good reason to use 4K cameras.
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castfeeder on 3/20/2017(UTC)
castfeeder  
#6 Posted : Monday, March 20, 2017 5:12:50 PM(UTC)
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Thanks everyone. Will test this out and report on results.
Digitalson  
#7 Posted : Monday, March 20, 2017 8:03:25 PM(UTC)
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Wow I was just going to ask this....I would think a vmix to vmix call would be better for that
mjgraves  
#8 Posted : Tuesday, March 21, 2017 11:07:57 AM(UTC)
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Digitalson wrote:
Wow I was just going to ask this....I would think a vmix to vmix call would be better for that


Why? Or maybe how is the better question.

vMix call is simply a convenient way to access a remote participant over the internet. Since it's via internet the video is must be massively compressed (1-4 mbps vs >750 mbps for 720p30.) Compression adds artifacts that make further production processes, like chrome keying, less accurate.

Seems simple. Of course, if your requirements are not that demanding you might find the results satisfactory.
DWAM  
#9 Posted : Tuesday, March 21, 2017 12:26:54 PM(UTC)
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Quote:
Of course, if your requirements are not that demanding you might find the results satisfactory.


Yeah! If your guest is Mr. Potato Head it might even work pretty well ! ;o)
mjgraves  
#10 Posted : Tuesday, March 21, 2017 3:17:22 PM(UTC)
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DWAM wrote:
Yeah! If your guest is Mr. Potato Head it might even work pretty well ! ;o)


After a little reflection, it might be worth an experiment to create some sample video and show the difference.

Some people have lousy chroma keys simply because their local lighting is poor. It strikes me that a remote guest, who is not in the habit of being chroma keyed, would not likely be in a great situation. Marginal lighting, little background/foreground separation, etc.
Digitalson  
#11 Posted : Thursday, March 23, 2017 12:39:41 AM(UTC)
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Well my first tests with vmix to vmix calls look pretty good !,and both have average or little faster net speeds,I can see a vmix call in a virtual set in green screen ,it's the delay that needs work
Digitalson  
#12 Posted : Thursday, March 23, 2017 12:40:49 AM(UTC)
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And worst case he would look like that video guy from the 80's,I forgot his name....
Len56  
#13 Posted : Thursday, March 23, 2017 9:18:13 AM(UTC)
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I think you are thinking of Max Head Room.
sinc747  
#14 Posted : Sunday, March 26, 2017 4:26:37 AM(UTC)
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Nothing like actually trying this out, right? Thanks to Tess and Paul of PTZ Optics who had me on their live streaming show on Friday so we had a chance to really try this out.

I am a guest on the show and Paul is bringing in my 1080p video using vMix Call and placing me in his virtual set. How very cool! Best of all, it took maybe 5 minutes to set it all up. And it was his first time using vMix Call. Well done Tess and Paul!



- Tom
zenvideo  
#15 Posted : Sunday, March 26, 2017 5:08:55 AM(UTC)
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Apart from the fact that the presenters' torsos are both floating a few inches above the top of the desk, it does indeed look fine in terms of the green-screen keying.

Something else to take into account in this example is that Tom's remote image has been scaled down a bit to be placed into the virtual set, which can effectively increase the resolution of the key, but even so it's clearly a perfectly usable technique.
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IceStream  
#16 Posted : Sunday, March 26, 2017 1:39:50 PM(UTC)
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@ sinc747

If I am not mistaken Tom, didn't you do something similar with Amnon a while ago using Skype (not sure if it was "Streaming Idiots" or "That VidBlaster Guy")?

@ zenvideo

I'm not familiar with that particular Virtual Set Martin, but I suspect that apparent space is supposed to be the somewhat reflective desktop (an area that Tricaster has excelled at in their Virtual Sets with realtime reflections, which I am sure vMix could accommodate with proper UVMapping in the set).


Ice
sinc747  
#17 Posted : Sunday, March 26, 2017 2:38:26 PM(UTC)
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IceStream wrote:
@ sinc747

If I am not mistaken Tom, didn't you do something similar with Amnon a while ago using Skype (not sure if it was "Streaming Idiots" or "That VidBlaster Guy")?

Ice


@Ice

You are absolutely correct. Here's that video:


But, the audio routing required to make that broadcast with Amnon work was far more than what we needed yesterday on the PTZ Optics show. Other than turning off the audio "follow" button, there was no special audio routing required.

And yes, it was the reflection or non-reflection that made us appear to float. Well, truth be told, Paul & I only have torsos in real life. Lol.

- Tom
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