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Color space confusion
My situation: I’m using AE to render off a home video. The AE project makes full use of the 0-255 color space range (meaning there are details on both ends of the spectrum which I do not want crushed). I have already created a version of the movie which followed these steps:
1: Render the entire project as raw uncompressed AVI. (Color management was off.) 2: Import that video into Encore and let it transcode as H.264, then create disc using the result.
I wasn’t sure what to expect. My understanding was that Blu-ray’s color space was 16-235, which had to mean that the codec would either crush the blacks/whites or scale them from 0-255 to 16-235. But here is what I observed. Each case involved a PS3 using identical settings.
1) One display (a plasma tv) showed the full range (0-255) and these values corresponded exactly to the display’s range. The display was properly calibrated.
2) Another display (a Sony LCD tv) had identical results to 1.
3) A third display (front projector) crushed the blacks and whites precisely to 16-235 (confirmed via use of a test chart which I generated playable H.264 video from).Confusion sets in. Just to round out the data, I went ahead and re-generated the test chart video, this time turning color space on and setting it to “HDTV (Rec. 709) 16-235”. The immediate result of making this adjustment was that After Effects now indicated the blackest black as “16” and the whitest white as “235”, even though the preview display did not visibly change at all. This was in keeping with what I’d understood about 16-235 video: That it would be correctly scaled by the display device to fit its full range (blackest black to whitest white), rather than being literally displayed as 16-235.
To make certain, I rendered the video off (again, as raw uncompressed AVI) and imported this into Encore to create a new disc. But the first display device (which displayed the first video’s full range of 0-255) did not do what I expected. Instead, it literally displayed a range from 16 to 235, which naturally gave the video a dull look.
I don’t have any good guesses as to what’s going on. What I do know is that until I figure out what I’ve done wrong, I have a choice: Either a video that displays properly on some displays but has crushed blacks and whites on others, or a video that looks dull and unprofessional on some displays but fine on others.
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3 Replies
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[Marc Brown] “Just to round out the data, I went ahead and re-generated the test chart video, this time turning color space on and setting it to “HDTV (Rec. 709) 16-235″.”
This would be a mistake, Marc.
The 16-235 SDTV and HDTV flavors are meant to be used as output profiles, not as working space for the project (note that the profiles meant to be used as working space are grouped together and offered at the top of the list). You don’t want to clip the color space in which After Effects renders images. You may want to limit the output.
So, if you want to test this, pick the non-limited HDTV REC.709 profile as the project working space, and then assign the HDTV REC.709 16-235 profile in the CM section of the Output Module (Render Queue). I am not recommending this workflow, just stating what would be the right way to achieve what you wanted to test.Adolfo Rozenfeld · Adobe
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Thanks for the reply. I gave this a shot, but as I half-anticipated, the resulting output was identical to what I got by setting the workspace as 16-235, as was the resulting Blu-ray video. In either case, what I was trying to figure out was why I couldn’t generate a video with AE which displayed the full color space without crushing anything, on different displays. Make no mistake: I know it can be done. Every single Blu-ray movie I own manages to do it.
I would say that the fact that even the experts in this forum sidestepped this query really says a lot about its perplexity.
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I don’t see a mystery here.
If it shows full range on any one display, it’s not clipped. That’s all there is to it. Everything else is related to internal settings and characteristics of each playback or display device. FWIW, a typical projector has a much lower range than most displays.Adolfo Rozenfeld · Adobe
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