Movie encodes waay too dark

[arch_angel16]

Using Gknot 0.27, DivxPro5.02, qpel, gmc, bframes. Set the compression at 95% of the compressibility check result. sharp bicubic resize filter, ivtc in dvd2avi, vbr mp3 160kb/s. Move is "The Bourne Identity" - and yes, I own it, bought it yesterday! ^_^ Great flick, but during the entire movie, light areas come out looking like unlight dark and shadowy... anyone tell me the reason this happens, and any possible solution? I know divx compresses darker areas more easily, but compressibility isn't really that big of a concern for me (within reason) and I don't like thie movie looking like a big shadow...You can't even see Matt Damon's eye sockets half the time, it's like he's the Avenger lol...

[valnar]

All my DivX movies come out too dark from the original DVD, and I haven't found simple way of fixing it. I'm surprised this isn't in a FAQ somewhere.

Since I use Gordian Knot and not VDub, I'd like to "brighten" it up the offsetting amount with an AVS Script entry (since you can do it before GKnot processes), but I don't understand the "Levels" script command syntax. Can anyone AVISynth experts help?

Robert

[leadman584]

There is an inherent luminance loss in Divx encoding, it is caused by compressing video to much smaller size. I believe they project @ 15% luminance loss in a compressed video. There is a very easy way to adjust for this in dvd2avi. In the video dropdown menu select luminance. Move the top slider to the right, it will introduce a gain of whatever value you like. I personally prefer between 20 and 40. Make sure you check the activate box in the upper right hand corner. I prefer this method to scripting it in the .avs, because you can see the video right there and the results of the gain you assert.
Hope this helps.

[valnar]

Yep, all my DivX movies are too dark. Damn, now I'll need to redo them.

I wonder why this isn't mentioned more frequently in this forum. I'll try a standard of 150,0 and see how that goes.

Thanks!
Robert

[ChrisBensch]

Here is the script I use, it adds a bit of brightness to the movie.

LoadPlugin("C:\Program Files\Software\DV\Video\MPEG2DEC\MPEG2DEC.DLL")
mpeg2source("E:\Video\Queen\Queen-DivX.d2v")

Crop(2,56,716,368)
CropBottom(2)

BilinearResize(640,272)
Levels(0,1.2,255,0,255)


The only part you need to be really concerned with is the '1.2' in the Levels. Normally it is 1.0...but increasing it gently increases brightness. 1.2 or 1.3 is about the most you should ever need.

Good Luck

[valnar]

Thanks. I had another reply that mentioned upping the luminance in DVD2AVI beforehand, but I think the AVS script has less washed out colors. I think I'll do that instead.

Robert

[movmasty]

Dont forget that u can perform brightness adjustements on the video screen itself, usually to play a video needs a much more bright screen than normal windows environment,
with the advantage that the more a movie is dark, the more it can be compressed down.
So im used to do video editing,depends from the "brightness " of your windows, setting screen gamma around 1.5, and some brightness and contrast too.
Then, if the movie is still dark, u can begin to light it with the levels filter,
but note that you should make the bright parts of the movie more dark as well to bright up the darker parts.
the same is with the contrast aspect of the movie, contrast means sharpness, less sharpness compresses better, so before u use a sharp filter, try to play with the contrast adjustement of the screen.

The levels filter works like a contrast filter with separate commands for dark,midtones and bright, 1st 2nd and 3rd settings in avisynth.
midtones adjustement is performed trought the gamma filter, that works keeping the darkest and brightest points, and proportionally more on darker points.
The 4rt and 5th numbers works on same area respectively of 1st and 3rd, but them make the dark less dark and the white less white.
The main value to adjust to "see what you didnt see" is the gamma,
yes use max 1.2 and with such high level may be useful to put the dark points to 3 or 4.
You can use also the white points at 235/245, if the white in the movie isnt already too bright.
And dont forget that settig up the gamma gives less contrast to a movie.

[valnar]

I'm encoding some dark TV episodes to DivX which appear darker when played back on my monitor as compared to the original DVD on my TV. I've used this to make it better (not an AVISynth expert here,,)

Levels(0,1.2,255,0,255)

You're suggesting it might be also beneficial if its too dark or bright to do something like this?

Levels(0,1.2,255,3,245) or so???

I've played with the brightness/contrast settings before in my WinDVD software and it washes out the colors more than encoding it straight into the movie. It's still not perfect, but better. It appears the LEVELS command does less damage to the colors in the DivX file than changing the Overlay settings on my video card for playback.

Assuming what Leadman584 above says is true, I just want to counteract what converting to DivX does to the video. I don't want it any percetively brighter or darker than the original.

Robert

[movmasty]

Originally posted by valnar
I'm encoding some dark TV episodes to DivX which appear darker when played back on my monitor as compared to the original DVD on my TV. I've used this to make it better (not an AVISynth expert here,,)

Levels(0,1.2,255,0,255)

You're suggesting it might be also beneficial if its too dark or bright to do something like this?

Levels(0,1.2,255,3,245) or so???

not really, you should touch last 2 settings only in special cases, and usually only the last, when you have a too bright white,
there is no point to make the black gray, and you wont see anything more.
i meant
(3,1.2,235,0,255)
dont confuse the white point setting(3rd number starting at 255)with the brightness, brightness works on all the image, washing darks and destroying contrast,
white point works only on the already bright points, doesnt touch the dark areas and gives itself more contrast to the movie)
instead when a part of movie is too bright,usually outside scenes,the settings to enlight darks scenes are not good, so you could encode them separately with (6,1,255,0,255/250)

about the adjustement in player/video card, works very fine here,
dont forget when you put gamma up, to give also more contrast.
(ad. the fact is that most player controls dont have levels or gamma settings, and use brightness to enlight a movie isnt any good also giving more contrast,
instead my vidcard settings have the gamma and works very fine, up to gamma at 2 in some movie)

[valnar]

If I adjust the gamma of an encode to 1.2 with LEVELS, what's a good contrast setting to offset the washing of colors within AVISynth?

Thanks for your lengthy reply. I'm learning something here. :D

Robert

[movmasty]

Originally posted by valnar
If I adjust the gamma of an encode to 1.2 with LEVELS, what's a good contrast setting to offset the washing of colors within AVISynth?
Thanks for your lengthy reply. I'm learning something here. :D
Robert
i meant
(3,1.2,235,0,255)
that little 3 at the left,could be also a 5, is that contrast adjust,
levels works like contast with independent settings for bright and dark.
but really i was talking about a contrast adjust in the screen,
however i never use more than gamma 1.1 in virtual dub.