Registered Member
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Hello,
I have a prores footage with alpha and I need to apply alpha premultiply rather than straight alpha. How to do it in kdenlive? Thanks! |
Registered Member
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Shotcut has an unpremultyply alpha effect which works perfectly, just FYI.
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Registered Member
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Could you perhaps describe a little more specifically what it is that you are trying to do and what it is that you are not succeeding with Kdenlive?
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Registered Member
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More preciely:
Kdenlive requires an alpha changing mode in footage properties or an effect to unmult the alpha channel. In vfx world some footage comes with straight alpha, some come as premulitplied alpha. Kdenlive I guess by default treats all alpha footage as straight alpha. We got some prores 4444 with alpha, which requires to treat it as alpha premultiplied. Which Kdenlive can't do. Shotcut has an alpha unpremultiplied effect. Which is working perfectly. The work around was converting the footage to qtrle with PNG. |
Registered Member
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Oh, I'm afraid I'll have to pass. I see that I had never dealt with this issue.
Let's hope that another user who knows about it will have something to say about it soon. Sorry. |
Registered Member
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Hi,
There is a frei0r plugin for that : https://www.mltframework.org/plugins/Fi ... emultiply/ but it has been blacklisted in Kdenlive in the category "# WORKING BUT NEED CHECKS" https://invent.kde.org/multimedia/kdenl ... s.txt#L174 Could you compile Kdenlive with this line removed and test it with your footage ? Cheers, Camille |
Registered Member
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This one should work. Shotcut is using it. Will compile it after finishing the project. Thanks. |
Registered Member
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Maybe these links help: http://dvd-hq.info/alpha_matting.php https://en.wikipedia.org/wiki/Alpha_compositing |
Registered Member
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Did a quick test and it seems to work fine. Would you like to send me some sample footage that you are using for me to test? |
Registered Member
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Here is a test file https://drive.google.com/file/d/1nzrN2K ... sp=sharing |
Registered Member
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Looks fine right? https://imgur.com/a/k7j4Kjl |
Registered Member
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Yes, this is exact. Thanks for checking it out! |
Registered Member
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Issue Created:
https://invent.kde.org/multimedia/kdenl ... ssues/1381 |
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