GPU ACCELERATION vs SOFTWARE ONLY : Changes with opacity quality

[Guillaume Chabot]

Hi,

I'm editing on a Mac with Premiere Pro 2019 (but I tried and I get the same issue with Premiere Pro 2020). I'm working on a project for a video production company. 50% of the editing was done from somebody editing on a PC, then I took over the project with my MacOS (Mojave). I used his own Premiere Pro 2019 project file. The other editor kept telling me he felt my exports didn't look as good as his. We made sure we were using the same editing and exporting settings. Then he sent me a comparison of one of his exports vs one of mine. There was a clear difference between the opacity of a green stripe in his export (darker and the constancy of the opacity looks better) and mine. But the problem didn't seem to be with the exports settings, because the green stripe looked the same in my timeline preview as it did in my exports.

I then thought about changing the preview renderer : when I put it in SOFTWARE ONLY mode instead of GPU ACCELERATION mode, the green stripe looks exactly the same on my Mac as it does on his PC in the timeline preview (darker, better). The export also looks the way it should when I export it with SOFTWARE ONLY rendering instead of GPU ACCELERATION rendering.

Now, I had noticed that sometimes, some heavy multi-channel effects require SOFTWARE ONLY rendering, or else there is a bug, like a black stripe that appears in my preview, which is also there when I export the video. I know that's a normal issue and I can deal with that, because it's clear when it happens. But if every video that I edit and/or export with opacity effects on -- and I don't even know if it's specifically about opacity effects -- isn't as good as it could be with GPU ACCELERATION, and if there is simply no way of knowing unless I compare everything I make with the two rendering modes, and not only for exporting but even when editing... Well then nothing makes any sense.

First, SOFTWARE ONLY can be incredibly slow while editing and even more so while exporting ; second, there is no mention of the issue I'm having anywhere on the web. So it can't be a "real" problem with GPU editing/exporting, can it? The issue would be all over this website. Basically everybody says to never use SOFTWARE ONLY if you have GPU ACCELERATION, because it should be the same thing, only slower. 

So, how is it not the same thing for me? Is my GPU now working correctly? How can I know?

I also linked a screenshot of my "About My Mac" information.

Thank you very much in advance,

GibbsGPU ACCELERATIONSOFTWARE ONLYABOUT MY MAC

[Kevin-Monahan]

Hi, This is likely your issue. https://community.adobe.com/t5/premiere-pro/quot-why-does-my-footage-look-darker-in-premiere-quot-co...

Lines on GPU accelerated exports could be a sign of a faulty GPU. Consult an Apple Service Center or Apple Dealer to check.

Not related, but please also consult system requirements, the CPU you have is 6th gen., which only meet minimum system requirements for version 14. Software Only might be better with an updated CPU. 

Thanks,

Kevin

[Guillaume Chabot]

Hi Kevin,

Thank you for your answer. I don't think the link you shared is my issue, because A) my footage isn't affected, it only seems to be when I use opacity effects on images on top of my clips (for the time being) and B) it doesn't darken, it actually lightens, and the quality of the transparency isn't on par.

Thank you for the advice, I will consult Apple Service soon if I don't get more clues in here.

Good point about the CPU, and if the GPU also is lacking, it might be time for me to buy a new computer...

Have a good day,

Gibbs

[chrisw44157881]

maybe try turning off maximum render quality. it changes things for some.

[Guillaume Chabot · Accepted solution]

Hi Chris,

Thank you for you answer. Though that wasn't it, searching about Maximum Render Quality brought me to this page (https://larryjordan.com/articles/premiere-pro-cc-what-the-heck-do-these-image-options-mean/)WHERE I FOUND MY ANSWER.

Information about this feature could help many other who struggle with the same issue, because it really isn't explained anywhere by Adobe :

"Composite in Linear Color

Adobe’s help files don’t cover this, at all. So, I found the answer on Creative Cow, written by Walter Soyka:

“Checking this box changes the mathematics used when blending images. It’s very common to [use] linear light in dedicated compositing workflows. Linear light will give you a very different look, usually with more natural-looking blends, but please note that some people find cross-dissolves in linear to be objectionably abrupt.

“See here for some background on linear light from Chris and Trish Meyers. Also, here’s my blog with more explanation and Premiere presets.

“Specifically to Premiere Pro: when using the GPU, Premiere always blends in linear light. You can use this checkbox to ensure that CPU-based renders will match GPU-based renders.”"

Thank you all very much.

Gibbs