Outline size on subtitle

[Anders M Olsson]

Much better!



I'd even say that the outline is a little too wide now. Perhaps there should be a setting for the width?

The subtitle still looks a little greenish, though. I don't know if my Windows-based DCP-players are to blame for that...? I've tried three different software players, and they all look the same. I don't have access to any real cinema equipment for testing right now.

[Alex Asp]

Hi Anders,

I usually set the WHITE color to RGB 233 233 233 values, which gives it slightly greyish tint, but is still white. Projecting on the screen, it looks quite nice without any color fringing.

Alex

[Anders M Olsson]

Thanks, Alex. I'll give your suggestion a try tomorrow.

[Anders M Olsson]

Sorry Alex, your suggestion only made the subtitles look even more green than before.



I think that might be a bug in DOM...

[Alex Asp]

Wow. I have never seen that. Are you using DOM on a PC?

[Anders M Olsson]

Yes, I'm running under Windows 10. I've tried to play the DCP using three different DCP-player programs, and it looks the same on all three of them. Considering that the film itself looks perfectly alright in color, I don't think it's a problem with the player software.

[Alex Asp]

it looks to me that you might have put the wrong value in the R field. If the R value is 0 and the rest are 233, then the colour is that kind of green.

[Carsten]

You definitely need to play these files on a calibrated DCI projector. Don't count on color fidelity with software-only players.


- Carsten

[Anders M Olsson]

I think that the difference between PC-players and real calibrated equipment is usually more subtle. Even if you can see the difference, it doesn't scream out in blaring green as in the examples I have shown.

I decided to do some more tests. First, I took a well known photo, a background picture from Windows 10. I painted in two white/gray rectangles of neutral color. One with the rgb-values 255, 255, 255 (the default color of subtitles in DOM) and one with the rgb-values 233, 233, 233 as suggested by Alex. I then converted the image to a DCP in DOM. This is the result:
http://hem.bredband.net/olsand/dcp/000010.jpg
The two rectangles are still neutral in color, even though they came out a little bit darker than the original.

I then ran DOM again, this time with a burnt-in subtitle on the upper rectangle. The subtitle came out almost invisible, since it's the same color as the background. That's good, and just as expected.
http://hem.bredband.net/olsand/dcp/000088.jpg

For a final test, I used the DCP from the first test as input to DOM, instead of the original image. I then burnt-in the same subtitle again. Now the subtitle has a noticeable green tint (but the background has kept its original neutral color). Not good, and not as expected, since both the subtitle and the background were originally white. You can't really blame the PC-player. Both the subtitle and the background are in the same picture, and are the subject of the same color management by the player.
http://hem.bredband.net/olsand/dcp/000095.jpg

My conclusion is that
- when the input material is a DCP (jpeg 2000), DOM will distort the color of burnt-in subtitles, (or perhaps "forget" to apply the correct color space conversion).
- when the input material is something else (rgb) - an MP4-movie, a BMP image etc. the subtitle color will come out alright.

I might be wrong, but I think that this must be a bug in DCP-o-matic.

[Carsten]

DCI and RGB use different whitepoints per specs. You shouldn't assume that 255,255,255 put's you on DCI reference white.

That would only be the case if DCO-o-matic would use a special input RGB colorspace mapping the 0-255 RGB range linearly to a XYZ RGB color representation. But that would be a fictitious color space of little use for all real applications.

You can of cause tweak it with a custom color conversion preset, it's easy for full white.


- Carsten