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Pure White BG for Web Video
I shooting video of our talent standing in front of a white paper backdrop, just as we’ve done for a very long time. We have our talent and backdrop lit separately, and the white paper is lit evenly. This is not the problem.
When in Final Cut Pro 6, the backdrop is completely white – perfect
In Motion, the backdrop is completely white – perfect
When exported as a Quicktime, the video still looks perfect. Along with that, if I take a still image of these three canvases and pull it into Photoshop CS3 to check with the eye drop tool… I read an RGB of 255 all around!Here is the kicker:
I need to convert this to an FLV. Using On2 Flix Pro, I convert the Quicktime video file to an flv, and I get blocks of a lesser white in patterns all over the backdrop.I have read forums all over Creative Cow, and others and I see others have reported similar issues. Most commonly it is suggested… Final Cut’s white cannot go as white as RGB-255. It only get’s to around RGB-235. And it’s suggested to use After Effects as it will get up to RGB-236.
Any help would be greatly appreciated! Thanks!
Ian
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8 Replies
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If Flash clips the whites at 235, you have two solutions:
– Use a 235 white (gray) for the web background.
– Isolate the subject with an Alpha channel. Flash supports it.
Rafael -
Sounds like the compressor is seeing some tiny bit of non-255 white and averaging that block of compression slightly darker. Why not apply a levels effect to it and clip the whites out completely so there’s no chance. I always assumed that’s what TV commercials and web clips did to get that perfect white background.
Make sure your timeline is rendering in super-white.
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[Bret Williams] “I always assumed that’s what TV commercials and web clips did to get that perfect white background”
What is pure white in a computer, is purely ilegal in a TV.
rafael -
[Ian Smith] “I have read forums all over Creative Cow, and others and I see others have reported similar issues. Most commonly it is suggested… Final Cut’s white cannot go as white as RGB-255. It only get’s to around RGB-235. And it’s suggested to use After Effects as it will get up to RGB-236. “
That is basically the problem. Video uses a narrower set of colors than computers use (16-235 vs. 0-255). I don’t have FlixPro, so I can’t speak to its capabilities, but the general rule is that you need to do some careful preprocessing of your video clip in order to stretch its contrast to the full 0-255 gamut. Squeeze has contrast, brightness and gamma filters to make these adjustments. The use of “super white” rendering only affects imported graphics if I remember right, so that won’t help your live-shot backdrop. I’m interested to find out how others approach this.
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You’d clip it with levels, and set the output white point to whatever you want. 200, 235, whatever. But the point being that anything above a certain white point would be completely clipped, with no detail whatsoever. Whether visible to the naked eye or not.
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This is all great input, however I’m still not there yet.
Here is another go to see what happens:
In Flix On2 (the encoding process), I used the “brighten” filter. I think one of you mentioned that in a post too. I resulted in an even white background, with an RGB of 254, 255, 252 (FEFFFC). It got rid of the block patters that were showing up, but I am still shy of pure white. If I boost the “brighten” filter any more, naturally I will also manipulate the brightness of the talent.I am going to toy around with this a little more, and I’ll report any findings.
Any more ideas are greatly appreciated! Thank you all for joining in the fun!
Ian
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I come to the same conclusion when using a white graphic. I created a white graphic in Motion, 1 second long. Exported the Qtime video and when encoded to an flv, I no longer have pure white. If I can’t get pure white with a graphic that is pure, there would be no chance of achieving the same with a white screen.
I wonder, is anyone able to get an flv with pure white? Maybe it’s my encoder? Would upping the bitrate help?
Thanks!
Ian
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Hey Ian,
As Bret suggested, the Levels filter in FCP can do a pretty clean job of clipping only those last couple of values close to white without affecting the rest of your values. Preprocessing in this way could get you closer to what you want and then a minor tweak inside the Flix app could get the rest. Your video will still need its tonal range expanded to look its best on computers, but at least you’ll have little to no variation in that background before you send it to Flix.
-Tom
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