Re: FxPlug adding color cast.
Re: FxPlug adding color cast.
- Subject: Re: FxPlug adding color cast.
- From: Emile Tobenfeld <email@hidden>
- Date: Tue, 13 Feb 2007 12:38:49 -0500
In my case I was applying to an image which includes a block of
pixels whose RGBA values are 255 0 0 255, and when I printf these
values I get 254 0 0 255. The image itself is not fully opaque.
I have tested this on ppc only,
At 12:14 PM -0500 2/13/07, Paul Schneider wrote:
Hi, list,
I think I may have misspoken earlier. We recently found an issue
with running YUV FxPlugs on PowerPC in 8-bit, where the image would
be darkened by one after going through the FxPlug. This is
something that will be fixed in an upcoming version. This issue
only happened in 8-bit YUV renders on PowerPC.
It sounds like the issue that Trevor reports happens with RGB
effects as well as YUV, and in float as well as 8-bit. This is not
something we're aware of, and not something we've seen internally.
You don't say if the issue happens on x86 as well; is this something
you're able to test?
Also, what kind of image are you applying the effect to? Does it
have a fully opaque alpha channel? Are the red and blue channels
significantly brighter than the green channel?
Thanks,
- Paul
On Feb 13, 2007, at 9:48 AM, Gabriele de Simone wrote:
So is this true in all cases? In other words, the workaround to fix
it under FCP 5.1.2 would be to add 1 to the output whenever the
plug-in is asked to render in 8 bit RGB/YUV, on PowerPC?
Emile: the color shift is actually visible on the computer screen,
but it is understandably quite small so you'll catch it easily only
with bright scenes (e.g. a sky) or by building a passthrough filter
and keeping an eye on the scope and toggling the filter on/off.
On Feb 12, 2007, at 7:31 PM, Paul Schneider wrote:
Hi, all,
sorry I was silent on this topic - it somehow didn't come across my radar.
This is in fact a bug in Final Cut, which only happens on PowerPC.
We've identified the problem, and a fix should appear in an
upcoming version. Sorry about the inconvenience!
- Paul
On Feb 12, 2007, at 7:10 PM, Dave Howell wrote:
Begin forwarded message:
From: Emile Tobenfeld <email@hidden>
Date: February 12, 2007 4:09:09 PM PST
To: Trevor Anderson <email@hidden>, Gabriele de Simone
<email@hidden>, email@hidden,
email@hidden
Subject: Re: FxPlug adding color cast.
At 3:29 PM -0800 2/12/07, Trevor Anderson wrote:
I found the problem. I logged the pixel data by running two plugins,
one after the other. Final cut is decreasing all values by one. If you
simply pass back the input values in the plugin, FC then subtracts one
from them, after fixing this in the plugin, passing back the input
data plus one, the cast went away and everything works as expected.
Seems like there is a bug in there somewhere, and it's in Final Cut
after it gets the frame back from the plugin.
Thanks to everyone who helped me out, I'm glad it was this simple, as
I really wanted to avoid the workaround.
Trevor
Good catch, Trevor -- though it sounds like the shift affects
all RGB colors and is not really a cast.
I'd noticed some 254's in my debugging code where I expected
255's , but had been too busy with other issues to dig further.
Dave, et al,
Can you comment on this. We don't really want to bump our input
values by 1 every time we are called.
--
"Now, here, you see, it takes all the running you can do, to
keep in the same place. If you want to get somewhere else, you
must run at least twice as fast as that!" -- The Red Queen
Emile Tobenfeld, Ph. D.
Video Producer Image Processing Specialist
Video for your HEAD! Boris FX
http://www.foryourhead.com http://www.borisfx.com
--
"Now, here, you see, it takes all the running you can do, to keep in
the same place. If you want to get somewhere else, you must run at
least twice as fast as that!" -- The Red Queen
Emile Tobenfeld, Ph. D.
Video Producer Image Processing Specialist
Video for your HEAD! Boris FX
http://www.foryourhead.com http://www.borisfx.com
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Pro-apps-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden