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Ph0en1x  
#1 Posted : Thursday, March 15, 2018 5:01:25 AM(UTC)
Ph0en1x

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If i capture a 2160p signal that i crop into four 1080p virtual inputs what gives me the best quality when my output is 1080p: a 2160p or a 1080p preset?
mjgraves  
#2 Posted : Thursday, March 15, 2018 10:30:11 AM(UTC)
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Not sure I understand the question completely.

If you use vMix 4k you can have a 2160p input, and crop/zoom it down to 1080p.

If the project is set for 1080p then you have effectively 1:1 pixel ratio of source:output. The quality will be very good.

If you use vMix HD you can have a 2160p input, but it will always be scaled down to 1080p. Any attempt to crop/zoom it will result in the image softening.
Ph0en1x  
#3 Posted : Friday, March 16, 2018 8:21:54 AM(UTC)
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mjgraves wrote:
Not sure I understand the question completely.

If you use vMix 4k you can have a 2160p input, and crop/zoom it down to 1080p.

If the project is set for 1080p then you have effectively 1:1 pixel ratio of source:output. The quality will be very good.

If you use vMix HD you can have a 2160p input, but it will always be scaled down to 1080p. Any attempt to crop/zoom it will result in the image softening.

I have vMix 4K. The question is what gives better quality scaling:

- Put 2160p camera into 1080p preset with 1080p external output and encode to 1080p (vMix scales?)
- Put 2160p camera into 2160p preset with 1080p external output and encode to 1080p (FMLE or FFMPEG scales?)
mjgraves  
#4 Posted : Friday, March 16, 2018 11:47:32 AM(UTC)
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I do believe that this is something you can answer for yourself. Setup a test scene and try both approaches.

I'd be curious to know how the load (CPU/GPU) differs. If you're using hardware encoding you might find that scaling at the output stage is less burdensome.
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