Apple

I also brought this up as a bug when FCP/Motion was first released for use by 3rd party plug-in developers.

The scale based on template size may make sense if you author in Motion and want the same look, as Darrin said. And the author of the template knows the original size of both the media when the template was made (that is, in Motion), and the resolution of of media applied-to FCP.

But that's the intent or purpose here. We developers are making the template based on some random size, because we have to in order to use the templates to get our plug-ins to work in FCP.

What we need is way to determine if (a) we are at the "normal" size for the media or (b) the media has been scaled by FCP. What we are given is the template-size scale information, which has no bearing on the footage we are working with, since the template is an empty placeholder.

Pete

From: Nathan Weston <email@hidden>
Date: Thursday, May 9, 2013 4:56 AM
To: Pro-Apps-Dev <email@hidden>
Subject: Re: RenderInfo scale factors are lying - FCPX only

On 05/09/2013 12:06 AM, Paul Miller wrote:

On 5/8/2013 6:40 PM, Darrin Cardani wrote:

On May 7, 2013, at 3:57 PM, Paul Miller <email@hidden> wrote:

On 5/7/2013 5:37 PM, Darrin Cardani wrote:

On May 7, 2013, at 6:55 AM, Paul Miller <email@hidden> wrote:

Here's a really frustrating one.

In FCPX, I'm working on a 1920x1080 clip, using TEXTURE mode, and

for some reason the scale factors are both 1.5. What is the reason

for this?

Typically I would look at the output image size and use the scale

factors to determine the full image size, but in this case the

scale factors are clearly wrong.

Is there another way around this?

Usually I see this when the input is something like 720 (1280x720)

being scaled up to fit within 1080 (1920x1080). Is your input the

same size as the Motion Effect was created at? If not, then the

scaling is likely correct. If so, then it sounds like a bug.

Ahhhh - that explains it. The media is 1080P but the motion template

was made at 720P.

But - how is this information useful? I need to know the full media

size in FCPX. In this case, the input/output images are at the full

media size (since FCPX doesn't seem to be doing any down-sampling).

But the scale factors indicate the media should actually be 50%

larger, which isn't true.

Well, it has to do with what our designers think users will expect

when using the app. If you apply a blur set to some value (say 5) to

an image in an SD project it gives you a certain look. If you have the

same footage in HD, a user will likely want the same parameter value

to give the same look. So a value of "5" should look "as blurry" in HD

as it does in SD. Using the scale information we provide, that should

happen.

Does that make sense?

We've run into this as well. IMO it doesn't make sense and is a bug. The

render scale should indicate the scale factor between the original

footage and the input/output images.

Yes, but I'm already doing that myself in my plugin logic, since my blur

values aren't in pixels - they are in "image units", which I can derive

accurately if I know the image size and downsample factors.

Maybe there is another way to determine the proper original media size?

In Motion (and other hosts), this is usually (image_size / scale_size),

but not in FCPX.

We worked around this by clamping the scale factors at 1. Scales less

than 1 usually seem to be correct and indicate downsampling. Scales

greater than 1 are always bogus, and when they occur the real scale

factor is always 1.

. . . . . . . . . . . . . . . . . . . . . . . . .

Nathan Weston email@hidden

GenArts, Inc. Tel: 617-492-2888

955 Mass. Ave Fax: 617-492-2852

Cambridge, MA 02139 USA www.genarts.com

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References:
	>Re: RenderInfo scale factors are lying - FCPX only (From: Peter Litwinowicz <email@hidden>)