Luma/Brightness Normalization?

[zoinbergs]

Dear my fellow members,

I just figured out how to perform FixBlendIVTC on my clip to remove the doubleblends I had from a bad 3:2 pulldown... and I guess you could say I'm moving on to another challenge!

It appears that FixBlendIVTC has output about half of its reconstructed frames as being a little, well, brighter than usual. Not brighter in the overall frame, but brighter in the higher values. It's creating a very slow, but noticable pulsing / flicker effect through my video, since only about 1/3 of the clip is actually affected.

Like, I guess you could say a lot of the time my brights are bit blown, or clipped if you will.

Does anybody happen to know where I can find a luma/brightness normalizer to fix this here problem, if such a filter exists?

I'm looking for something that performs the same concept of work that volume leveling does with audio.

Now I don't want to raise the overall brightness, or lower it, but I'd rather like to detect spikes in brightness, and correct just those spikes. I don't think a flicker filter will work, since the spikes don't exist between fields, but rather frames.... but I could be wrong.

Maybe a two pass filter would work best.. where the first pass scans for spikes, and the second pass goes through and only applies normalization on those spikes.

I dunno if it can be done...... what I do know is that I'm heading in the direction of becoming a developer though, because I cannot stop thinking about this stuff! I have never been so entertained and challenged at the same time with any other hobby.

So I'll be on the lookout for this here filter I need, and will post back with my results later. In the mean time, if anybody can help me out, it'd sure be nice to hear from you!

Thank you for reading this extremely long post. :D Have a good day now!

Chao,
William

[foxyshadis]

I think all that needs is to fix FixBlendIVTC. I'll check it against the chunk you posted earlier, some range expansion may have crept into the latest version. As for the question you asked, HDRAGC would be decent for that, though it would do a lot more as well.

[zoinbergs]

I think all that needs is to fix FixBlendIVTC. I'll check it against the chunk you posted earlier...

Tehe, I thought the exact same thing myself! But I tried all the settings I could think of, and still no luck. :(

Also, that clip I provided in another thread happen to be a really clean section of the video, that was a perfect candidate for FixBlendIVTC.

Here's a clip that when FixBlendIVTC'ed, gives much more of a distance in brightness for its recovered frames, than for their surrounding frames:

http://www.sendspace.com/file/x5z8kw

If you encode this clip using

DeBlock(quant=25) # Improves output by at least 100% ;)

FixBlendIVTC(sbd=false, post=1, mthresh=0.0)
Decimate(cycle=5, quality=0)

The effect is kinda like a, umm, bad sharpening tool if you will! Much more contrast than usual, IMO. The brights are just too darn bright not to be noticable.



Thank you in advance for trying the new clip out if you do Foxy! I really do appreciate the help you're giving me. :)

[zoinbergs]

Well, I have absolutely NO idea why the heck I didn't use "post=2" first, before trying anything else...

But that totally did the trick!

And encoding a DeBlocked version of my clip beforehand, for FixBlendIVTC to base off of as an alternative, (as opposed to deblocking in the same script), made a substantial improvement as well. :)

I am QUITE satisfied with this handy little filter.. it is exactly what I have been looking for!

Thank you MO & Foxy. ;)