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Color distortion in video capture and GPU role in process?

Question asked by a_h on Jan 3, 2017
Latest reply on Jan 11, 2017 by angryuser1
  1. Hi.

 

I have a very sticky problem when doing a live streaming event. I am capturing an RGB 32bit signal (DVI) and we notice that the colors are distorted, despite of the fact that there’s no YCbCr <-> RGB color conversions etc. This is checked visually and using color picker without saving the image (paste to paint).

When I capture the video using the capture card manufacturer’s own capture window we see that the colors are ok but when using a third party encoding software (Telestream Wirecast, Adobe FMLE, OBS) I see the distortion.

 

My questions are: what is the role of the GPU in this process / relation between the GPU and encoder software? What is the color processing chart in this capture case over all (trying to find the factor of this behavior)?

I also noticed that using the older AMD software I can adjust the color slightly, but not reaching the exact values. Still I wonder if in this process it is ok to adjust colors using GPU overall (like in YCbCr to RGB conversion you lose part of the colors and you’re not able to restore them but only twist them to a desired tone).

 

I have done live streaming for years but now for the first time I’m trying to reach the perfect color precision since our customer has millions of viewers and is demanding a perfection. I’m streaming to YouTube, Twitch, Facebook and our partner CDN. We also know the playback site will distort color in some cases, but we try to minimize it by doing the perfect on our end.

 

I’m using AMD Radeon R7 200

Win 7 up-to-date

Computer: Asus X99-S

Ram 16GB

Capture card: Datapath Vision AV-SDI using DVI input

 

Any help is highly appreciated since I'm not that familiar with the process details.

 

- A_H

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