Best luma brightening filter for VirtualDub?

[callmebc]

Hi

Since the beginning of October I've been using a Kodak Zi8/Sony ECM-DS70P mic combo for recording concert videos. I've gotten comfortable using VirtualDub and some add-on filters (mostly Color Mill and the MSU stuff) with a Kodak Zi6 I used a lot before getting the Zi8. There's been, though, a few times when I was recording a very dim but good sounding show that none of VirtualDub's filters could brighten evenly or effectively without becoming cartoonish. The problem seem to be when the luma falls below a certain level, VirtualDub sees little or nothing to brighten. I noticed though that the AV controls in VLC were more effective at brightening, but VLC doesn't redirect to file well at all. But then I discovered that Avidemux's filters can be as effective as VLC for brightening when stacked. However, aside from brightening, I much prefer VirtualDub (Avidemux's preview mode is nearly worthless when I use extreme brightening), and in extreme cases will use Avidemux for a rough adjustment and then use VirtualDub for the final work.

It would be nice, though, if there was a luma brightening filter I can just get for VirtualDub. I've looked, and all the ones I've tried have not been nearly as effective as Avidemux's. If there is something out there that you think might do the trick, do let me know. Thanks in advance for any tips.

-BC

[filmboss80]

Go back into VirtualDub's internal filters and choose "levels." It is very flexible and can change luma while preserving black and chroma levels. The best filter is already there for you. You just have to know how to use it. Experiment with short clips.

[callmebc]

Thanks for the quick response, but I had already played around with that, but like the other VirtualDub filters, it causes a posterized/cartoonish effect at its extreme settings. This is for a situation like where the only lighting in a big space at night might be Christmas lights on the wall and a lamp in the far corner, and what I'm recording doesn't even show up in the Kodak's viewfinder, and I have use points of lights or reflections to figure out where people are positioned -- we are talking dim-dim.

[jagabo]

The best thing to do is open your Video with AviSynth and ConvertToRGB(matrix="PC.601") or ConvertToRGB(matrix="PC.709") so you don't lose blacker-than-black in VirtualDub. Then try Levels or Gradiation curves to get blacks at 0, whites at 255. Or, even better, do all your adjustments in AviSynth and use VirtualDub only for final compression in Fast Recompress mode.

[redwudz]

You might try a gradation curves filter with VirtualDub. I find it useful for darkened scenes or ones with low contrast. http://members.chello.at/nagiller/vdub/index.html But with a darkened scene, raising the brightness level will only help so much, as there is usually little detail there and it will tend to be grainy, especially in the darker areas. You might have to play with saturation, contrast and maybe even soften the processed image a little to lessen the grain effect. You can likely improve it, but it will never be like a normal scene with correct lighting.

Another handy filter with a lot of built in effects is ColorMill. I use it quite a bit for basic processing. You can find it and a lot of other VD filters here: http://www.thedeemon.com/VirtualDubFilters/detailed.html

[callmebc]

Thanks again. I was thinking of trying AviSynth since many if not most of the Avidemux filters are AviSynth ports, so I'm assuming that I would get the same brightening effect. And I love and use Color Mill but it too doesn't really help with dark, dark shadows.

For an example of what I'm talking about, this is the first video that really stymied me with VirtualDub:
http://www.youtube.com/watch?v=-5bwRtOOOmc

As you might gather from the "wall lighting," there wasn't exactly a lot of illumination going on.

This is video from the same night, but here I tried first using Avidemux to brighten it and do other rough adjustments, and then I used VirtualDub with Color Mill and some of the MSU filters for final fixing:
http://www.youtube.com/watch?v=U3jAJTEd4Fs

Much better results, but what a time consuming pain.

One thing I'm very curious (and hopeful) about is that the VLC people are supposedly coming out with a universal video editor in the not too distant future.

[jagabo]

Some VirtualDub filters will work in YUY2 mode. Use the Brightness/contrast filter after forcing Video -> Color Depth to YUY2. That will allow you to bring out dark shades that VirtualDub's usual RGB conversion will obliterate. I don't know what happens if you use an RGB filter (eg, Gradation curves) afterwards -- whether it converts to RGB before Brightness/contrast or afterwards.

You should upload a sample of your original source. There's no telling what YouTube has done to the video.

[callmebc]

Hmmm....thanks, I think you may have hit on the problem -- I did a search on VirtualDub and YUY2 and came across this rather informative page: http://www.animemusicvideos.org/guides/avtech/colorspace.html

Check towards the bottom for what it says about VirtualDub and RGB. That kind of implies that VirtualDub is inherently hopeless when the luma falls below a certain level because RGB loses, or just doesn't see, that info (I did your suggestion of changing the color depth, but didn't seem to affect how any of the filters work). But AVISynth and its filters can work in YUY2, which is probably why Avidemux works, since its filters are based on or are ported from AVISynth. So, if true, it looks as though I would have to preprocess very dim videos to boost their luma before VirtualDub can be useful.

Does that seem right?

[jagabo]

Yes, that's what I was talking about. But recent versions of VirtualDub can do some filtering in YUY2 (maybe other YUV colorspaces too but I haven't tried any of them). My suggestion to use AviSynth's ConvertToRGB() earlier would eliminate this problem by avoiding the usual contrast stretch performed by VirtualDub when it converts to RGB (the two specified matrices perform the conversion without the contrast stretch).

[callmebc]

Cool, thanks a bunch -- I think I have a handle at least on the problem. I guess I just need to figure out a simple Luma boost preprocess. I did try downloading VirtualDub 1.9.8 but I didn't see any difference in filter behavior, at least among the several brightness related ones I have.

I've attached a frame image from a recent video I processed and uploaded to YouTube to give you an idea of the lighting conditions I sometimes work with.

[callmebc]

Oh yeah, I should show the result of running a stack of Avidemux filters on it: http://www.youtube.com/watch?v=7tlRA1Q9bbg

That included the Luma equalizer, Contrast (with its contrast setting to its max), MPlayer eq2 with its contrast jacked up and added saturation, both FluxSmooth and Mplayer hqdn3d denoisers, and sharpened twice with "Sharpen" and once with MSharpen.

[jagabo]

If you want to adjust the brightness within VirtualDub you must force the color depth to a YUV mode. And only certain filters work in YUV. Brightness/contrast does. Levels and Gradation curves do not. But you can adjust the brightness and contrast first, to get levels between Y=16 and Y=235 (about bright +6, cont 87%), then then conversion to RGB for the other filters will result in RGB=0-255 with no black and white crush (I verified this).

You'll get better results using ConvertToRGB(matrix="PC.601") or ConvertToRGB(matrix="PC.709) in AviSynth:

DirectShowSource("Filename.ext")
ConvertToRGB(matrix="PC.601")

Then there will be no black/white crush when imported into VirtualDub. And the best results will come from doing all your filtering in AviSynth.

Here's a grayscale HuffYUV encoded AVI file where all pixels have a Y value between 0 and 16:

huff.zip

And VirtualDub's recovery in YUY2 mode with the indicated filters:

[callmebc]

Cool -- I got to try that. Thanks again.

[Soopafresh]

There's also HDR agc for avisynth http://strony.aster.pl/paviko/hdragc.htm

[redwudz]

I've been wondering, I had a couple of videos from Japan where the brights were completely blown out, with no detail visible. Darks are non-existant. Probably no way to correct this as that data is already missing, but I'm guessing that may have been from a bad color depth conversion?

[callmebc]

Update: while VirtualDub can indeed brighten that 20th Century Fox clip, it still can't do likewise with dim videos from my Kodak Zi8. I think the real issue is with the plug-in I'm using for VirtualDub to open MOV files -- it's not doing a proper conversion. When I got my older Zi6, I had scoured the Internet long and hard for a way to open up MOV files directly without using a converter. I found a forum posting somewhere with an effective how-to that involved using an older version of Quicktime Alternative, which apparently had one or two system codecs the newest versions didn't have. That worked.

Not too long after getting my Zi8, I was setting up a new computer for doing video, and despite searching high and low, I could not find that posting with the trick of using the older Quicktime Alternative. I did though come across a few mentions of an alternative method using a VirtualDub plugin. I installed that, but now I think I may have lost the ability to brighten really dim videos with VirtualDub. I ended up switching to Avidemux because of that.

Would anyone know about that trick of using an older Quicktime Alternative? The only reference I've been able to Google up is a small posting on thedeemon.com with a link to Quicktime Alternative 1.76 on Filehippo. I think that's the version I had originally used, but I seem to remember one other proviso in that you had to use an older version of VirtualDub as well.

In any case, I'll likely at least try out using Avisynth (that HDR AGC plug-in looks very intriguing.)

But again thanks for all the help and good tips so far.

[jagabo]

Update: while VirtualDub can indeed brighten that 20th Century Fox clip, it still can't do likewise with dim videos from my Kodak Zi8. I think the real issue is with the plug-in I'm using for VirtualDub to open MOV files -- it's not doing a proper conversion.

It sounds like the MOV plugin (or Quicktime itself) is doing the YUV to RGB conversion (with contrast stretch) before it gives the video to VirtualDub. I wouldn't trust automatic dynamic range filters. Just do the adjustments yourself in AviSynth with ColorYUV() or Tweak(). Or, as suggested earlier, just use AviSynth to convert to RGB without the contrast stretch and then use VirtualDub:

DirectShowSource("filename.mov")
Info() # verify colorspace of the source, remove this line later
ConvertToRGB(matrix="PC.601") # or "PC.709"

[visible0]

By know there are new programs that deal with low lighting, but here 1of 8 filter combos within virtualdub [this combo not the best of the bunch but uses the most available filters]
here the "The Good Ship Kangaroo" by Ronan Quinn wMatt Glover at Precinct 11110 sen t through the filter combo VIDEO IS UNLISTED:http://www.youtube.com/watch?v=5rc8qMVRUEg

THE BEGINNING of the video show comparison stills and filters used but the latter in resizing ruined it clarity here the filters in this 'png' capture:. Of the remaining filter combos 3 can do better, but in 2008 i sent them to freeware developers in exchange they donate to charities hence not posting that.

[callmebc]

By know there are new programs that deal with low lighting, but here 1of 8 filter combos within virtualdub [this combo not the best of the bunch but uses the most available filters]
here the "The Good Ship Kangaroo" by Ronan Quinn wMatt Glover at Precinct 11110 sen t through the filter combo VIDEO IS UNLISTED:http://www.youtube.com/watch?v=5rc8qMVRUEg

THE BEGINNING of the video show comparison stills and filters used but the latter in resizing ruined it clarity here the filters in this 'png' capture:
[Attachment 7823 - Click to enlarge]. Of the remaining filter combos 3 can do better, but in 2008 i sent them to freeware developers in exchange they donate to charities hence not posting that.

This is a rather belated reply, but I only just saw this (I came across it, actually, when I was searching for some info on filters that can tone down bright spots due to high contrast lighting, and spotted this thread on the Google search results.) I did want to say at least thanks for the suggestion. My old Zi8 is pretty much retired now, though, having been replaced as my concert cam by, currently, either a Sony HX9V/Zoom Q2HD combo, or just the Q2HD by itself (which is the *only* real replacement/upgrade for the venerable Kodak Zi8/Sony ECM-DS70p mic combo.) The HX9V was at the time I bought it the best compact video camera outside of much more bulky and expensive DSLRs, and the Q2HD can handle very high audio sound levels more cleanly than any digital audio recorder that I know of (it's even better than my Zoom H2n). This is a video I posted just this morning: http://youtu.be/beMqsrA-MHc

The video was massaged 2 ways, mostly to do with the lighting (which is always an issue at this particular venue): first a general cleanup by Avidemux, and then a second pass with Video Enhancer using VirtualDub filters (while I got VE to help resize old videos, its ability to run VD filters much more quickly than VD itself has proven to be a nice little time saver.)

FYI. Thanks, if somewhat belatedly, for your reply and suggestion.

[sanlyn]

There's also HDR agc for avisynth http://strony.aster.pl/paviko/hdragc.htm

Nope. Can't happen. Wrong approach.