DVD-RB 0.93.1 sets CCE Luminance Level to 16-235

[uteotw]

Hey there

I opened the rebuilder.ecl file with CCE 2.70.02 and browsed around the settings.

In the advanced settings I found out that the Luminance Level is set to 16-235.

Isn't this limiting the colors space?

A while back I searched back about that settings and the differences beteen 16-235 and 0-255. After experimenting I agreed that setting the Luminance level to 0-255 was better and it is the settings I use when backup manually my DVDs.

I was wondering if this was a mistake or if jdobbs did this on purposem? If so why?

May be an option could be added into the CCE Expert settings to select 16-235 or 0-255 ?

uteotw

[Fishman0919]

If you are watching DVD's with a standalone player on a reg TV (most people do), 16-235 is correct because you won't be able to see the diff.... regular TV's can't display 0-255

[uteotw]

When I visually compare a dvd re-encoded with CCE using Luminance 0-255 the colors look really better on a normal TV or LCD monitor. I'd say it's matching the source dvd (which I suspect are created using 0-255) compared to when use 16-235, it looks a bit "washed out" or faded, the color are slightly grey'sih.

[alfixdvd]

I Agree, using Luminance 0-255 on CCE the colors look really better on a normal TV or LCD monitor, with 16-235, it looks a bit "washed out" or faded

[Fishman0919]

From CCE FAQ Q12 by RB http://forum.doom9.org/showthread.php?s=&threadid=53770

Q12: How do I set the "Luminance Level" option correctly?

To make it short: it doesn't matter unless your video is in RGB format. I know some people will argue about that but I'll prove it below *).

MPEG1/2 (and that's what CCE encodes to) uses a color format called YCbCr which is vastly different from RGB. So CCE needs to convert RGB to YCbCr if the input clip uses RGB colors and does so by applying a conversion formula described in the CCE manual. The "Luminance Level" setting specifies a factor in this formula that controls whether the luminance range of the conversion complies with the ITU-R BT.601-5 standard (16-235, applicable for display on TV) or is more applicable for viewing on a computer screen (0-255). You decide what's best for your viewing application. But basically, if you want to retain the original luminance level of the RGB video, set it to 0-255 as 16-235 compresses down luminance.

So, how do you know if your video uses RGB colors? I know of only the two following scenarios where this can happen:


You are frame serving a DVD2AVI project into CCE via VFAPI. VFAPI always converts to RGB. And this is also the only time where the YUV -> RGB Scale setting in DVD2AVI matters. Because DVDs usually already comply to the ITU-R BT.601-5 (16-235) standard) , you will want to use "PC Scale" in DVD2AVI and "0-255" in CCE in this case to avoid any luminance compression.

You are using the CCE Adobe Premiere plugin. Premiere feeds RGB video to the plugin and it depends on the DV codec used whether it performs any luminance scaling during the conversion. For instance, the Canopus DV codec has an option "Expand RGB range to 150%" for the YUV-RGB conversion which means luminance would be stretched to 0-255 during conversion. Again, you generally want to avoid any luminance scaling and set Luminance Level to 0-255 in the CCE plugin.

DVD2AVI projects frame served into CCE via AVISynth/mpeg2decX.dll do not use RGB but the YUV color space which is basically just another name for YCbCr. So no conversion takes place and you can ignore both the YUV -> RGB Scale setting in DVD2AVI and the Luminance Level setting in CCE.

*) Here is the proof: take any short clip you know is in YUV color format. For instance, the following short AVISynth script ensures you get a YUV colors clip:
ColorBars(720,480)
ConvertToYUY2
Trim(0, 299)
Now encode that clip in CCE into two different files, use "0-255" for the first and "16-235" for the second encode. Perform a binary comparison of both MPV files (use a command line fc /b clip0_255.mpv clip16_235.mpv). They will be identical.


So 0-255 or 16-235 doesn't matter for dvd, dvd is YUV color format and is mostly 16-235.... and reg TV and dvd players can't display 0-255 anyway... it won't hurt doing 0-255 but you gain nothing for TV

[Video Dude]

The Luminance Level setting does absolutely nothing unless you input RGB. Since a DVD is YV12 and DVD-RB converts it to YUY2 via AviSynth when using CCE, checking 0-255 or 16-235 will produce exactly the same output since there is no RGB conversion.

[uteotw]

yep, that makes sense... I researched that in the old days of DVD2AVI... didn't really thought about it since.

Thanks for the help everyone.