Weird Brightness Problem - How to fix with Avisynth?

[VideoFanatic]

I usually use "Cont" and "Bright" to fix brightness issues but this particular clip has a weird brightness issue that I don't know how to fix: http://www.mediafire.com/?x914mjgp6kexk4g

[jagabo]

Reduce gamma. It still won't be great because of the crushed brights.

You might be able to tease out a little more detail with gradation curves.

[sanlyn]

Your sample is mpg. What is the source? Was this originally on tape? If so, how was it captured? I echo jagabo here: you can play with various filters, but most of the midtones, brights and a much detail are destroyed or distorted.

[AlanHK]

Try the built in Levels filter http://avisynth.org/mediawiki/Levels

or more options using YLevels. (Need to install in Avisynth plugins folder.) http://avisynth.org/mediawiki/Ylevels

[jagabo]

before and after ColorYUV(gamma_y=-150, gain_y=20, off_y=12):



Tune to your liking.

[sanlyn]

I used several methods, including the one above, but you can see that upper midtones and brights are almost gone - not even the darker white shirts in the crowd have much detail. How does the original video look played directly to TV?

[VideoFanatic]

The video is from a VHS to DVD conversion I purchased from someone. I don't have the original video. The sample I showed you was dumuxed from the DVD to an MPEG2. I played it on my TV but I just looks the same as on my PC - it's too bright. So is the problem that the detail is gone in the bright areas or is it just that the brightness cannot be corrected?

[jagabo]

Yes, the problem is that the detail is gone in the bright areas, even though they are within the legal Y range. There's no getting those bright details back.

[sanlyn]

Might be able to salvage something out of it. Hold on . . .

[sanlyn]

- Copy a VOB of this video from your DVD disc to your computer.
- Run DGIndex.exe, and open the VOB you copied.
- In the DGIndex Video menu, click "YUV > RGB" and select PC Scale
- In the DGIndex Video menu, click Luminance filter. You'll see a dialog as shown below.


[Attachment 11768 - Click to enlarge]

The settings I chose will lower gamma but protect the black levels. Careful of your settings: keep an eye on the figure in dark clothing so that you don't crush black detail. The mids and brights can be adjusted later.

- In the File menu, select Save Project, give the d2v a name and location.

You can open the d2v project with MPEG2Source in AVisynth. Your source will be the d2v file, not the VOB. Try this script:

MPEG2Source("J:\forum\brightness\BrightnesSample.d2v")

AssumeTFF()
COlorYUV(off_y=+5,gamma_y=-5)
ConvertToRGB24(matrix="Rec601",interlaced=true)

#--- crop noise off bottom ---
# --    and uneven sides  ----
Crop(4,4,-10,-12)
AddBorders(7,8,7,8)

You should be able to tweak from there in RGB, or you can adjust and crop in YUV if you want. This might be easier to color- correct in RGB.

I did some quick RGB color with ColortMill and gradation curves.This would be a start, anyway. There's a lot of grungy interlace combing and other noise. Those problems would have to be cleaned up in Avisynth before you get to RGB color.


[Attachment 11769 - Click to enlarge]

[VideoFanatic]

Thanks for your help but I did that Luminance Filter in DG Index then used the code you provided but it still looks really white. I don't think this can be fixed. Thanks anway.

[sanlyn]

You can't use that script to completely correct the images, or to fix every scene in the video. The DGIndex settings and ColorYUV can only do so much, which is to bring your video into a practical luma and color range and help retrieve some detail. In VirtualDub you still need to tweak within that adjusted range. Try ColorMill, it's pretty easy to learn.

This seems to be one of several problem videos you've reported as being transferred for you by friends.

[VideoFanatic]

Yes that's what I got too but it still looks really white. What's your point about me saying the videos were from friends?

I don't find Colormill easy at all! I can't even find a documentation page which explains how to use it.

[jagabo]

I used levels and gradation curves in VirtualDub and got a little more detail in the bright whites:

[VideoFanatic]

Thanks but I did mention in the title that I wanted to fix it with Avisynth.

[sanlyn]

Yes that's what I got too but it still looks really white. What's your point about me saying the videos were from friends?

I don't find Colormill easy at all! I can't even find a documentation page which explains how to use it.

ColorMill is downloaded as a ZIP file. The ZIP contains the .vdf plugin, and it contains this file (ColorMill.txt):

Color Mill Filter for VirtualDub
(Version 2.0)
Based on Red/Green/Blue (RGB) Adjustment Filter for VirtualDub
by Donald A. Graft

[Place this text file in the VirtualDub plugins directory to make
it available via the Help button on the filter configuration dialog
box. The computer must have a program called Notepad available in
its search path.]

This filter provides the ability to more precise adjust the red, green,
blue and balance intensity levels and saturation of a video clip. 

The following options are provided:

Red - This option determines how much red is to be scaled.
Green - This option determines how much green is to be scaled.
Blue - This option determines how much blue is to be scaled.

These three options are applicable on three states:
Dark - to adjust dark areas;
Middle - to adjust middle areas;
Light - to adjust light areas.

Also this filter provides the ability to adjust intensity levels and
saturation on the three separate states:
Dark - to adjust dark areas;
Middle - to adjust middle areas;
Light - to adjust light areas.

For example: to remove colored glares you can decrease saturation->Light.
Do you like cut-and-try method? :)

In Ver.1.03 added effect booster "Bad source". You can try it.
In Ver.1.05b added RGB gamma.
In Ver.1.07 added sHSV with hue similar to real hue.
In Ver.1.08 added real HSV Adjustment by Donald A. Graft.
In Ver.2.0 added Middle Point adjustment and Sharp <-> Smooth adjustment

Eugene Khoroshavin
December 13, 2004
(C) Copyright 2004, All Rights Reserved

Every control button and slider on ColorMill has a name or numbers on it. There's also a button labeled "Preview". Haven't you ever opened a color filter (or any filter) in VirtualDUb and worked the buttons and sliders to see what happens?

[sanlyn]

Thanks but I did mention in the title that I wanted to fix it with Avisynth.

That's doing it the hard way, but it's possible. There are specific instructions for using ColorYUV and Tweak. And RGBAdjust. You'll need a specific script for every video, and even for several scenes in each video that requires special treatment. If you're just learning, VirtualDUb is easier.

Did you try jagabo's YUV suggestion posted earlier: https://forum.videohelp.com/threads/345016-Weird-Brightness-Problem-How-to-fix-with-Avi...=1#post2152239

[jagabo]

Thanks but I did mention in the title that I wanted to fix it with Avisynth.

You can call virtualdub filters from avisynth.

A little further into the gamma?

 ColorYUV(gamma_y=-230, gain_y=-170, off_y=178)

[sanlyn]

How's this? Avisynth only. Use the same .d2v you created earlier (the DGIndex routine sets manageable gamma and black levels, as described earlier). You'll need the SmoothAdjust plugin.


[Attachment 11784 - Click to enlarge]

LoadPlugin("K:\Avisynth 2.5\plugins\SmoothAdjust.dll")
MPEG2Source("J:\forum\brightness\BrightnesSample.d2v")

AssumeTFF()
COlorYUV(off_y=+10,gamma_y=-40)
ColorYUV(cont_y=15,gain_y=+20)
SmoothLevels(0, 0.8, 255, 16, 255)

#--- crop noise off bottom ---
# --    and uneven sides  ----
Crop(4,0,-10,-10)
AddBorders(8,4,6,6)

[jagabo]

Or, jagabo's previous post also works (but don't use that sme .d2v project, jagabo's code doesn't need the DGIndex settings I used!).

Yes, I used the default settings in DgIndex (luminance filter disabled).

Attached is a video with the last script (+QTGMC). I think it went a little too far in darkening the mid shades. And the saturation needs to be lowered a bit now that the gamma is so different. I'll leave that up to you.

[sanlyn]

Nice, jagabo. QTGMC did a good cleanup.