problem with green line/green bar on the video

Bug report and feature request
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MarcinZ
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problem with green line/green bar on the video

Post by MarcinZ » Mon Sep 28, 2015 8:01 pm

Hello!

I have the following problem. I convert 4K XAVC S 100 Mbit/s video into 4K HEVC 50 Mbit/s video using GPU with NVENC acceleration.
Unfortunately the converted video contains green bar on the top and bottom of the video. I read that the problem is connected with the fact that height of 4K video is not divisible by 64 (because 64 is the block of pixels in HEVC 4K video).
That`s why I decided to crop the video and set the new cropped "frame" from to 3840 x 2160 pixels into 3840 x 2112 pixels.
Unfortunately the size of the video didn`t change. Then I decided to change the resolution using scaling. Resizing video works well, but unfortunately there is a big another problem.
When I don`t change the size of the 4K video the speed of conversion on my Asus GTX 980 TI graphics card runs 2.8-3 x times faster than the length of the video.
When I change the size of 4K video mentioned before via scaling the conversion on my Asus GTX 980 Ti graphics card drops down to 1.3-1.5 x times faster than the lenght of the video.
Such decreasing is not acceptable, that`s why I have some questions to you:

a) how to fix the problem with green line with no changing the size of the 4K video to 2112 (height)? I mean with no scaling?
b) why doesn't the problem with green line/bar appear when I use another software (Divix Converter) where I don`t change any resolution?
c) why does the 4K video plays with no green lines in the source video file which also have height not divisible by 64 (2160)?
d) how to make cropping work fine in Media Coder Premium? I have tried crop to fit and expand to fit options but none of them works and the resolutions was still the same as source.
e) does crop the video impact on the speed of conversion on the same speed level as scaling?

Please help me
Regards
Marcin from Poland

stanley
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Re: problem with green line/green bar on the video

Post by stanley » Thu Oct 08, 2015 6:23 pm

Frame scaling is done by CPU by default that's probably why enabling it slows down the speed. There is an option on Picture besides "Effect" button. Change it to "Encoder Filters" to utilize GPU scaling when using GPU encoding.
When things work together, things work.

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