real automatic level correction based on histogram?

[kopmjj]

Hi i want to know is there a such program or plugin thatsdoes that? basically i have a video and when checking histogram on levels i set the white and black point, but when i go to a diferent scene the histogram changes etc so for each scene or frames theres a diferent level of histogram is there a tool that does it automatic or do i have to do this frame by frame?

[edDV]

If these are TV recordings, there is equipment at their end that does just that prior to transmission.

If your VCR, DVD recorder or other capture device has an automatic gain control (AGC) set to on, it will potentially ruin the carefully set levels so turn it off.

If you are seeing black shifts from a poorly maintained cable or sat provider, a single correction for each channel should be sufficient.

If these are camcorder recordings, the automatic exposure system probably causes each clip to require separate correction.

[edDV]

If these are TV recordings, there is equipment at their end that does just that prior to transmission.

If your VCR, DVD recorder or other capture device has an automatic gain control (AGC) set to on, it will potentially ruin the carefully set levels so turn it off.

If you are seeing black shifts from a poorly maintained cable or sat provider, a single correction for each channel should be sufficient.

If these are camcorder recordings, the automatic exposure system probably causes each clip to require separate correction.

[kopmjj]

thanks for your replys :P so i wont be able to do this on my pc on a uncompressed avi and use after effects or avisynth? so i have to transfer the video to a vhs and use hardware editor to fix this?

[edDV]

thanks for your replys :P so i wont be able to do this on my pc on a uncompressed avi and use after effects or avisynth? so i have to transfer the video to a vhs and use hardware editor to fix this?

What is your source?
How was it captured?

[kopmjj]

thanks for your replys :P so i wont be able to do this on my pc on a uncompressed avi and use after effects or avisynth? so i have to transfer the video to a vhs and use hardware editor to fix this?

What is your source?
How was it captured?

source was captured from vhs from a freind onto the pc uncompressed, and that tape is gone now. basically on some scenes its too dark on other its normal and also has too much saturation and color noise and the face color is not natural but i gues i can change that using hue edit.
so im stuck with the uncomressed file.

[jagabo]

ColorYUV(autogain=true)

[manono]

You might also try HDRAGC:

http://strony.aster.pl/paviko/hdragc.htm

[jagabo]

And MSU Smart Brightness for VirtualDub.

[kopmjj]

You might also try HDRAGC:

http://strony.aster.pl/paviko/hdragc.htm

i tried that but it went too bright i want to brightern darks but not whites is there a way? also when i brighten darks the black level is light black and when i up the contrast i lose detail any way to prevent that.

can you give me an example of hdrgc? for my situation thanks.

[jagabo]

Use Histogram() or VideoScope() to examine levels graphically. It sounds like you want gamma correction more than anything else.

[kopmjj]

Use Histogram() or VideoScope() to examine levels graphically. It sounds like you want gamma correction more than anything else.

can i upload a sample video so you can see what im talking about? its a concert footage of mj.
when i up the brightness on some parts its fine others parts too bright, please help me balance this.
ill upload in a bit

here is the video http://www.megaupload.com/?d=5FX3RJEM

[edDV]

VHS VCR's usually have an AGC setting luminance record levels. These can be very inaccurate. Compounding the problem, older cable and sat systems have poor black level control so you get can get a few IRE variation in black to blanking and black to sync tip levels when switching channel to channel which add to AGC error. That means you need to manually adjust black video clip to video clip and then make a subjective judgement on contrast (luminance gain).

Few VHS VCR's (or capture cards) auto correct chroma saturation errors. In other words, if you correct luminance levels (black to zero IRE and peak white to near 100 IRE), then chroma saturation will usually be close and not need adjustment.

Software auto level correction filters like those described will use an algorithm to estimate where black and white levels are. Depending on video content, these can also add inaccuracy. Manual correction will get better results. First adjust black, then make a judgement on white (contrast) for that clip. It helps to have a waveform monitor to assist with major levels errors, then add subjective corrections based on video content. Don't adjust chroma saturation until you are sure luminance levels are correct. There should be no hue errors in the PAL system.


PS: Your "Megaupload" file shows as unavailable.

[edDV]

So many issues with this file.

First you are in the UK. I was expecting a PAL capture file but it is NTSC 720x480 size and frame rate.

Second, why the Cinepack codec

Third, why is the field order lower field first? What was the capture device?

The capture is clearly 0-255 rather than 16-235.

Media Info
General
Complete name : G:\billie jean.avi
Format : AVI
Format/Info : Audio Video Interleave
File size : 35.9 MiB
Duration : 17s 824ms
Overall bit rate : 16.9 Mbps
Writing application : VirtualDubMod 1.5.10.2 (build 2540/release)
Writing library : VirtualDub build 32593/release

Video
Format : Cinepack
Codec ID : cvid
Duration : 17s 317ms
Bit rate : 17.0 Mbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 3:2
Frame rate : 29.970 fps
Standard : NTSC
Bits/(Pixel*Frame) : 1.637
Stream size : 35.0 MiB (98%)

Audio
ID : 1
Format : AC-3
Format/Info : Audio Coding 3

[edDV]

The file shows heavy field blend artifacts (poor deinterlace)

After black and white levels were set, it subjectively needed gamma correction.

[edDV]

More gamma correction

I suggest you find a better source.

[jagabo]

That's some sad video. Try VirtualDub and Gradation curves -- something like this:

[kopmjj]

yeh the source is very bad but thats the best available for this concert very rare, so im guessing its too hard to fix? and also advisable to fix gamma first before color right? if you find more fixes please upload screen thanks.

also i only saved the sample to cinepack codec otherwise its uncompressed and interlaced. i will use a better deinterlace.

what software is that on the screenshot?

[manono]

what software is that on the screenshot?

Read what he said:

Try VirtualDub and Gradation curves

And I'd recommend you not deinterlace it at all. Either that, if it's PAL2NTSC (need a sample from the source to be sure), unblend it.

[kopmjj]

what software is that on the screenshot?

Read what he said:

Try VirtualDub and Gradation curves

And I'd recommend you not deinterlace it at all. Either that, if it's PAL2NTSC (need a sample from the source to be sure), unblend it.

ok here is the interlaced sample 5mb http://www.megaupload.com/?d=PD3HBKXT

[manono]

I can't make the link work. Maybe someone else will have better luck. Did I ever tell you how much I hate Megaupload?

[kopmjj]

http://www.mediafire.com/?nkjzq2hyzw2

[lordsmurf]

Unless the Jackson estate is paying for it, I wouldn't even bother. There are ways to forensically restore selected clips and stills from something that bad, but it will never be a piece that can be watched for enjoyment. It's too far degraded for anything of that nature.

I would leave it as shades of middle/dark gray, and then adjust a TV set darker if needed. I wouldn't further ruin the video, as leveling has downsides, too.