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Forums Adobe Premiere Pro Composite In Linear Color Setting

  • Composite In Linear Color Setting

  • Ben Mullins

    October 1, 2013 at 8:45 am

    Hi,

    In the Sequence Settings (in PPr CC) there is an option to select ‘composite in linear color’ – what does this do and should it be checked by default or does it depend on the footage you’re editing with (I’m using 5D footage at the moment)? What differences will you notice between checking/unchecking this box?

    Thanks,

    Ben.

  • Walter Soyka

    October 1, 2013 at 9:26 pm

    [Ben Mullins] “In the Sequence Settings (in PPr CC) there is an option to select ‘composite in linear color’ – what does this do and should it be checked by default or does it depend on the footage you’re editing with (I’m using 5D footage at the moment)? What differences will you notice between checking/unchecking this box?”

    Checking that box changes the mathematics used when blending images. It’s very common to 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:
    https://s3.artbeats.com/articles/pdf/linear_light.pdf

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

    Walter Soyka
    Principal & Designer at Keen Live
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    RenderBreak Blog – What I’m thinking when my workstation’s thinking
    Creative Cow Forum Host: Live & Stage Events

  • Paul King

    October 2, 2013 at 9:07 am

    Blending is broken in Premiere because of support for CUDA.
    This is an attempt to fix it and doesn’t work properly.
    You get all sorts of issues.

    Why don’t they just fix what’s broken?
    No other app has various ways of blending images – there is only one way – the correct way.

    These issues have been around since CUDA was implemented and it’s still broken 3 years later.

    It’s not good enough for a professional video application.

  • Walter Soyka

    October 2, 2013 at 7:18 pm

    [Paul King] “Blending is broken in Premiere because of support for CUDA.”

    It’s not broken, but it is different than what most editors are accustomed to. NLEs have historically been quite naive about color and compositing and have usually blended with non-linear gamma.

    [Paul King] “This is an attempt to fix it and doesn’t work properly. You get all sorts of issues.”

    Or — this an option that gives you more natural-looking compositing, even if you don’t have a GPU, and works exactly as linear compositing should.

    [Paul King] “No other app has various ways of blending images – there is only one way – the correct way.”

    Now that’s just silly — and demonstrably false. All high-end compositing systems support linear light. Some, like NUKE for example, only work in linear and don’t support your “one correct way” at all.

    [Paul King] “These issues have been around since CUDA was implemented and it’s still broken 3 years later. It’s not good enough for a professional video application.”

    I agree that there should be an option for gamma-encoded blending when rendering on the GPU, just as there are options for gamma-encoded and linear blending when rendering on the CPU.

    But really, if I recall correctly, your problem isn’t with linear blending at all; it’s with single-clip cross dissolves, because linear changes the look of a straight cross-dissolve. You want the slower entrance on highlights that a gamma-encoded, video-style cross dissolve gives you. You could get the same thing in linear light if you could bend the completion curve for the transition.

    I agree it’d be cool to have a “non-linear” checkbox in the standard Cross Dissolve transition, but you can work around this by animating a clip’s opacity. I’ve made a couple of presets that mimic non-linear dissolves using linear compositing [link] which you might find handy.

    Walter Soyka
    Principal & Designer at Keen Live
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    RenderBreak Blog – What I’m thinking when my workstation’s thinking
    Creative Cow Forum Host: Live & Stage Events

  • Will Eccleston

    October 2, 2013 at 7:42 pm

    Agree wholeheartedly with Paul. There might very well be uses for linear color, but this shouldn’t be something anyone has to know or think about when it comes to applying dissolves or transparency in a non-linear editor. Paul stated: “please note that some people find cross-dissolves in linear to be objectionably abrupt”. I would contend that it’s really not a matter of preference at all. They’re just wrong. And it’s one of the most fundamental things done in a video editor. All may not experience it, and different video cards will of course produce different results. But as of now, using CUDA on 2 different machines with different (both qualified) cards produces very poor results, making CUDA acceleration unusable for me. A fix would be very nice.

    Will Eccleston
    Kinetiscape Films

  • Will Eccleston

    October 2, 2013 at 7:47 pm

    And making dissolves manually with opacity curves, even if you can copy and paste them…seriously? Do you have things to do other than edit?

    Will Eccleston
    Kinetiscape Films

  • Walter Soyka

    October 2, 2013 at 7:54 pm

    [Will Eccleston] “Paul stated: “please note that some people find cross-dissolves in linear to be objectionably abrupt”. I would contend that it’s really not a matter of preference at all. They’re just wrong.”

    I stated that, not Paul. I am sure he would agree with you wholeheartedly.

    I don’t really disagree that a single-sourced cross dissolve in linear is “wrong.”

    While I’m glad Premiere has linear compositing, I think the fact that simple switching from software MPE to hardware MPE changes the look of compositing operations by default is a poor design choice.

    [Will Eccleston] “There might very well be uses for linear color, but this shouldn’t be something anyone has to know or think about when it comes to applying dissolves or transparency in a non-linear editor.”

    Again, I can agree that the default behaviors should be more editor-friendly, but having an option for linear compositing is a great feature for anyone doing even a little compositing in their NLE.

    Try the presets and let me know if they work for you. I know it’s not as good as a proper transition because the keyframes don’t track the clip’s extents on the timeline when you trim it, but they are pretty fast to adjust or even remove and reapply if you need to trim a title or something like that.

    [Will Eccleston] “different video cards will of course produce different results”

    They should not. Premiere uses CUDA or OpenCL on the GPU to crunch numbers, not OpenGL to process images. You should get the same results on any GPU. If that’s not what you’re seeing, it’s a bug that should be reported and fixed.

    Walter Soyka
    Principal & Designer at Keen Live
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    RenderBreak Blog – What I’m thinking when my workstation’s thinking
    Creative Cow Forum Host: Live & Stage Events

  • Walter Soyka

    October 2, 2013 at 7:57 pm

    [Will Eccleston] “And making dissolves manually with opacity curves, even if you can copy and paste them…seriously? Do you have things to do other than edit?”

    My, how pleasant.

    Like you, I’d prefer a non-linear dissolve in Premiere. I happen to also prefer hardware acceleration. This is my workaround to get both with a single drag and drop, and I decided I could share it with the community. I’m just trying to help.

    Walter Soyka
    Principal & Designer at Keen Live
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    RenderBreak Blog – What I’m thinking when my workstation’s thinking
    Creative Cow Forum Host: Live & Stage Events

  • Will Eccleston

    October 2, 2013 at 8:00 pm

    And I got a bit snarky there…and I would be remiss not to say that you are, in fact, enormously helpful here, and not just in this forum. It is very much appreciated! But doing dissolves with keyframes is not a solution for me. I hate stepping backwards.

    Will Eccleston
    Kinetiscape Films

  • Walter Soyka

    October 2, 2013 at 8:39 pm

    No worries. I agree that keyframes are a step backwards. I just disagree with Paul’s contention that linear compositing is “wrong.”

    In my mind, and in my feature request, the real solution is a gamma adjustment with sensible defaults in the dissolve effect. Best of both worlds.

    Walter Soyka
    Principal & Designer at Keen Live
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    RenderBreak Blog – What I’m thinking when my workstation’s thinking
    Creative Cow Forum Host: Live & Stage Events

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