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Apple Keyer - more basic errors (for Walter) - EDIT

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Simon Ubsdell
Apple Keyer - more basic errors (for Walter) - EDIT
on Feb 2, 2014 at 2:39:25 pm
Last Edited By Simon Ubsdell on Feb 3, 2014 at 2:28:57 pm

I know this subject has become very boring by now so apologies for reverting to it yet again but I just wanted to add a couple of newly discovered observations about what's happening with edge pixels in the Apple keyer.

Firstly, applying the keyer to any image source results in cropping off all the edge pixels, leaving a small but crucial gap.

Here's the clip with the keyer applied but disabled.


And here it is with the keyer enabled (the blue line is the background showing through).


There simply are no edge pixels for the blurring operation to work with so you'll get very serious erosion of the edges when using the lightwrap function.

Secondly, using the soften and/or erode option in the keyer results in the same shrinkage of the edge pixels that I pointed out in connection with the lightwrap. (Actually this problem is far more severe, and also irritating in practice, than the lightwrap issue - apologies for not having spotted it before.)

Here's the soften function in action:


It is obvious from this why the blur (soften/erode/lightwrap) is never going to work properly - there simply isn't any edge detail for the operation to work with because the keyer has cropped it off. The blur operation doesn't know there's an edge of the frame that needs to be taken into account because no pixels are allowed to reside there.

Why it's being cropped off I have absolutely no idea, I'm afraid.

My original diagnosis was that the blurring operation had not been carried out correctly (and Walter provided a very elegant demonstration of how this can happen and what needs to be done to rectify it), but it's the absence of any edge pixels which is the real culprit.

If you run into situations where any one of these issues causes you grief, you can work around them by scaling up your clip slightly and then creating a compound, before applying the keyer.

But you really shouldn't have to.

None of these things is a disaster in actual practice - though the fact that you simply can't get hair to key properly is going to be deal breaker for the more discerning user in the majority of cases.

Obviously to many people it will seem I am being picky, but then I think we have every right to be picky when it comes to Apple.

Don't offer a keyer at all unless it's going to be the very best you can do. At the very least don't leave it riddled with obvious and simply rectified mistakes.

And think about showing it to someone who actually knows something about compositing before releasing it to the public - a trainee compositor in their first few months will be able to spot these mistakes pretty easily.

There are many good and interesting things about FCP X (and Motion, don't let's forget Motion, my personal favourite!) but this lack of attention to detail is really dismaying and doesn't bode well.

Can I urge you to submit feedback to Apple on this so at least it's not just me complaining on my own?

EDIT: The cropped edge pixels (as described above) don't seem to show up in 10.1 but the edge erosion issue is still unresolved. It does suggest that my previous theory is the correct one, i.e. incorrectly executed blur operations. But I guess it doesn't really matter why it happens, it just matters that it happens.

Simon Ubsdell
http://www.tokyo-uk.com


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Walter Soyka
Re: Apple Keyer - more basic errors (for Walter) - EDIT
on Feb 6, 2014 at 8:58:50 pm

[Simon Ubsdell] "Firstly, applying the keyer to any image source results in cropping off all the edge pixels, leaving a small but crucial gap. "

Well, that's certainly curious.


[Simon Ubsdell] "EDIT: The cropped edge pixels (as described above) don't seem to show up in 10.1 but the edge erosion issue is still unresolved. It does suggest that my previous theory is the correct one, i.e. incorrectly executed blur operations. But I guess it doesn't really matter why it happens, it just matters that it happens."

Even more curious. Did they fix the bug on purpose, and just miss or ignore everything else? Or did they fix it accidentally?


[Simon Ubsdell] "There are many good and interesting things about FCP X (and Motion, don't let's forget Motion, my personal favourite!) but this lack of attention to detail is really dismaying and doesn't bode well. "

Hasn't it been ever thus with Apple? Fanatic attention to detail over the user experience, maybe sometimes at the expense of attention to the boring bits?


[Simon Ubsdell] "Can I urge you to submit feedback to Apple on this so at least it's not just me complaining on my own?"

Sure, I'll be on Motion tomorrow or early next week, I'll dig around a bit myself and send some feedback.

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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Simon Ubsdell
Re: Apple Keyer - more basic errors (for Walter) - EDIT
on Feb 6, 2014 at 10:09:18 pm

[Walter Soyka] "Even more curious. Did they fix the bug on purpose, and just miss or ignore everything else? Or did they fix it accidentally?"

It is very curious - I can't work out what that gap came to be there in pre-10.1 versions although it doesn't seem to be connected after all to the blur problem evidenced in the soften/erode/lightwrap issue which is of course unresolved.

[Walter Soyka] "Hasn't it been ever thus with Apple? Fanatic attention to detail over the user experience, maybe sometimes at the expense of attention to the boring bits?"

They will have many floors full of people agonising over the roundedness of corners in the interface, but it's still just the one man and his dog working this stuff to all appearances.

And most days it's just the dog manning the shop.

Simon Ubsdell
http://www.tokyo-uk.com


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