-
Render increases brightness/contrast
I am woking on a show currently. I have some shots where I have created a text box that I rendered with an alpha channel. The clip with an alpha was brought into Final Cut Pro. The overall look of the clip should be video starts, and then part way into the clip, this box appears with the text. But when I have the box clip start, it increases the brightness/contrast of the video clip under it. Why would this occur? Is there a way to fix it? I have tried to adjust the brightness/contrast to have the shots match, with no success. The end all be all fix would be to take all of the video clips into After Effects and render that out to have them all match this increased video, but its a 12 min HD uncompressed timeline, and thats not a desirable solution. I did this show last year with same kind of text boxes and zoom blur effects, and didn’t have this problem. Any help would be greatly appreciated, because like you all have experienced, I’m running up to a deadline of today and have already been through the ringer all week and sleep deprived. Shots originated in FCP, dual 2 GHz 4 GB RAM, with an AJA kona 2 card.
Thanks
Brian -
11 Replies
-
What version of FCP, how have you rendered the alpha channel and you have properly selected the type of alpha you have rendered in the FCP browser?
-
I have FCP5.1.2, rendered alpha is 32 bits/pixel.
Can you please explain “properly selected the type of alpha you have rendered in the FCP browser?” -
Well, depending on if you have rendered a straight or pre-multiplied with black (which is what I usually render) you import the clip into FCP and then scroll to the right in the browser and choose the alpha type (straight, black, white, none). You can also right click the clip and choose it from it’s item properties. Make sure to do this before you add it to the timeline. If the clip is already in the timeline, you must right click the clip and do this in the item properties.
Jeremy
-
I think this have may have to do more with FCP than AE
In FCP,
1 select your sequence
2 cmd 0 (sequence settings)>video processing tabThere is a little heads up about color shifts.
I’m not sure what codecs you are using, but you may want to try rendering in one of the two “render in high-precision YUV” options. I think you may have your sequence set to “Always render in RGB”.
-
Also be sure to render in trillions of colors.
-
I too have experienced this in the HD realm. It seems to me that using the Apple uncompressed 10 bit codec for rendering is making the rendered video brighter. I think using the Kona v210 codec for rendering yields better results.
However, I have had problems working in After Effects itself. I think it is something where the RGB conversion in After Effects makes the video seem brighter. This is making it pretty much impossible to do accurate color correction.
-
Have you rendered in trillions??? You have to modify the AE preferences file to do so, usually.
Jeremy
-
I have not tried to render in trillions, mainly because when I use the Kona v210 codec, it seemed to be dead on accurate.
My problem is more of using HD footage inside AE. It seems to me that the footage appears brighter in AE than it does looking at it in quicktime. I understand that AE is using it in its RGB world where the quicktime player looks at it in yuv. So there seems to be some gamma display problem.So if AE is making it appear brighter, then I color correct it and bring the levels down. But, when I render it, the footage now looks crushed. So I do not see how it is possible to do accurate color correction, when After Effects is displaying the footage brighter than it really is.
Anyone else have this issue in the HD world?
-
It doesn’t matter if you are in HD or SD, gamma is gamma, and it will vary depending on where you are watching the movie from. If you are using a Kona card, look up tables are used on the Kona card to correct for the gamma. They also offer options for your own look up tables if you so desire. What you see is what you get. You should never critically judge a quicktime movie from your computer screen, especially for color. If you do in fact have a Kona card, I’d suggest using the KOna TV application to look at your rendered quicktime.
The Kona v210 codec was made to make up for these deficiencies. Apple has recently updated their uncompressed codec, and rendering in trillions seems to do the trick.
Jeremy
-
Thanks for the info Jeremy. How do I go about acquring the newe Apple Uncompressed codecs?
If I take a quicktime movie that I capture and open it up in quicktime, and also import that quicktime into After Effects, I see a change in brightness (I think it is a gamma issue, though I am not sure.)Are you saying, that with this new codec, that After Effects display and Quicktime will look exactly the same? You see, since AE is displaying the captured quicktime movie a little brighter, it is making it impossible to color correct. I have not even gotten to the rendering stage yet. I am just trying to understand why an HD movie looks so different in AE than it does in Quicktime.
I would like to acquire that new codec, so if what you say is true, at least I can do the color correct in AE and be certain that when I render, it will look exactly the same as the After Effects display.
Thanks in advance.
Reply to this Discussion! Login or Sign Up