SNOW scene is too Bright <<

[amira]

hi

After burning dozens of dvds from VHS home recordings, I started to notice over exposed scenes especially in snowy

background or scenes with camera facing the sunlight.

When i playback my VHS on my VCR everything is fine. I think it is happening during the capture.
I use Scenylizer, PinnacleDV500, S-Video or Composite.

Please check the attached image. It is supposed to be normal where you can see the faces of the people in the car. But as you can see it is too bright (over exposed).

Please advice.

[BJ_M]

whoa - even i can not fix that

[edDV]

8 bits (256 levels) is a tight "window" for capture. You need to "ride the gain" for white levels scene by scene during capture to handle the wider range of black to white than 256 levels can deliver. When the gain is too hot, you get clipping, loss of gray scale in sum a washed out image.

8bits is tough and labor intensive to get levels set properly. Broadcasters demanded 10bit digitization for this reason and film look equipment is going for 12bit. Higher bit capture means you can do AGC (contrast) in post (i.e. during editing) even if the target DVD is only 8bits.

[MOVIEGEEK]

Yeah I get the same when I capture using my analog capture card,you might try lowering the brightness in Overlay.Another option is to use an analog to digital converter such as a Canopus ADVC-100.

[Sifaga]

what car

[SHS]

Sifaga that not a car

[Blazey]

Looks like MV to me. This is what all my caps look like without the SIMA SCC in the signal path.

[amira]

Thanks guys

Do you have any suggestions as to how to eliminate this brightness?

[Marvingj]

Video level needs to come down. You need a Color Corrector like Elite BVP 4 or Signalone, a professional corrector.

[edDV]

Video level needs to come down. You need a Color Corrector like Elite BVP 4 or Signalone, a professional corrector.

Key issue to understand is that levels need to be correctly set before capture for 8 bit systems. There is not enough dynamic range to correct seriously hot or low white levels. The image shown above cannot be fixed with a digital filter. The data is not there.

It needs to be recaptured with the correct setting for white level.

[Marvingj]

If you cannot recapture but need a quick fix, then used a professional color corrector. It can help, but won't do miracles.

[BJ_M]

i do color correction commercially -- believe me .. that image above is not correctable in post

[amira]

I'm capturing home tapes. So I guess I'll recapture them again.

- So what Professional Color Correctors would you recommend, in case i go for that option?
- In case of recapturing what settings I should use? What things I should keep in mind? I use Scenyliazer or Premiere.
- Would you recommend any other capturing softwares? Or should I buy a new capture card?

Thank you for your help

[edDV]

I'm capturing home tapes. So I guess I'll recapture them again.

- So what Professional Color Correctors would you recommend, in case i go for that option?
- In case of recapturing what settings I should use? What things I should keep in mind? I use Scenyliazer or Premiere.
- Would you recommend any other capturing softwares? Or should I buy a new capture card?

Thank you for your help

The Pinnacle DV500 should have white level (also saturation hue etc.) settings for the analog inputs in the capture menus. If your Premiere is recent you have the waveform monitor, get the whites under 100IRE. If its an older Premiere, you may want to do some trial and error caps until you find the right white level.


Added: Here are the controls for the DV500

[amira]

Thanks,

Brightness adjustment didn't help. I tried Brightness, Contrast, Saturation etc. And it didn't seem to affect the video problem i'm having.

It pisses me of after spending lot of hours and money into this project and i end up with this video issue. I don't know if I can afford Professional Color Corrector etc.

I'm open to peoples ideas and experiences.

[non-linear]

Get a standalone DVD recorder. I find they are much better at maintaining proper video levels than PC capturing methods. I can't tell you how many times I've dicked around with the levels on my ATI card and still never have consistent capture levels.

[junkmalle]

Thanks,

Brightness adjustment didn't help. I tried Brightness, Contrast, Saturation etc. And it didn't seem to affect the video problem i'm having.

It pisses me of after spending lot of hours and money into this project and i end up with this video issue. I don't know if I can afford Professional Color Corrector etc.

I'm open to peoples ideas and experiences.

Try using GraphEdit: https://www.videohelp.com/tools?tool=GraphEdit

Start the program, select Graph -> Insert Filters, scroll down to Video Capture Drivers, select your capture card, press the Insert Filter button, followed by Close. Back at the main window right click on the capture filter box and select Properties. On the dialog that pops up select the Video Proc Amp tab. You should get a list of properties like Brightness, Contrast, etc. With my Hauppauge WinTV PVR-250 I can see the changes in realtime as I move the sliders.

[edDV]

Thanks,

Brightness adjustment didn't help. I tried Brightness, Contrast, Saturation etc. And it didn't seem to affect the video problem i'm having.

It pisses me of after spending lot of hours and money into this project and i end up with this video issue. I don't know if I can afford Professional Color Corrector etc.

I'm open to peoples ideas and experiences.

Those controls only operate while capturing video. Since the DV500 has no waveform monitor, you need to repeat capture in a trial and error fashion until you find settings you like.

[SLK001]

Your problem is that your encoder thinks that your scenes with snow (or stars) are full of noise, so it can't encode it properly. You'll probably find the bps at these scenes to be MAX'ed out. Your problem when you "film the sun" are truly brightness issues. Try a different MPEG encoder.

[edDV]

Your problem is that your encoder thinks that your scenes with snow (or stars) are full of noise, so it can't encode it properly. You'll probably find the bps at these scenes to be MAX'ed out. Your problem when you "film the sun" are truly brightness issues. Try a different MPEG encoder.

It's a capture to 8 bits (256 levels) problem.

In the first post amira said
"When i playback my VHS on my VCR everything is fine."

[amira]

It's a capture to 8 bits (256 levels) problem.

I think it's one of the very likely possibilities.

So what it is supposed to be? EdDV's first explanation of 8bit 256 levels is too complex for me. In a simple way should I just get a new capture card or what?

By the way the video i was capturing is in PAL system.

[edDV]

The DV500 is a capture card and the capture input setting menu is posted above. Unless you are prepared to spend >$200 you won't do any better. That was a $1000 card when new.

Experiment with "Brightness" and "Contrast" until you get an acceptable picture. You will capture, evaluate, adjust and repeat until you get it right. Then adjust saturation for color level.

If you do buy somthing new, it needs adjustable input levels like the DV500.

A good solution would be the Canopus ADVC 300
http://www.canopus.us/US/products/ADVC300/pt_advc300.asp#specs
http://videosystems.com/mag/video_canopus_advc/

or the mid range Pinnacle hardware
http://www.pinnaclesys.com/productpage_n.asp?product_id=2480&division_id=2

Unless the DV500 is defective, it should do the job fine. If not, use a video service bureau that will have higher end 10 bit capture hardware.

[SLK001]

Your problem is that your encoder thinks that your scenes with snow (or stars) are full of noise, so it can't encode it properly. You'll probably find the bps at these scenes to be MAX'ed out. Your problem when you "film the sun" are truly brightness issues. Try a different MPEG encoder.

It's a capture to 8 bits (256 levels) problem.

In the first post amira said
"When i playback my VHS on my VCR everything is fine."

No, it's an encoding issue. Just because there are only 8 bits doesn't mean that the full range of brightness isn't available. It just means that the "steps" between levels isn't as fine as a 10 bit system.

As for the "When I playback my VHS..." statement, it just means that the original doesn't have this problem.

To eliminate the card as a problem, just convert a few seconds of the area around the snow scene to an AVI format, then view this. If the same issue exists (and I doubt that it will), then I would get a better card.

It's not uncommon for scenes of dust, snow, rain or stars to give MPEG encoders fits.

[amira]

The fresh captured AVI looks like this before encoding into MPEG.
So I will do some more experiments in the next day or two.

Thanks

[davideck]

Thanks,

Brightness adjustment didn't help. I tried Brightness, Contrast, Saturation etc. And it didn't seem to affect the video problem i'm having.

It pisses me of after spending lot of hours and money into this project and i end up with this video issue. I don't know if I can afford Professional Color Corrector etc.

I'm open to peoples ideas and experiences.

I had the same problem with my Hauppauge PVR-250. The video proc adjustments for the card did not help. But I was able to improve things quite a bit by adjusting the brightness and contrast on my Datavideo TBC-3000. I upgraded from a TBC-1000 for just that reason; I find the video proc controls on the TBC (prior to the capture card) to be very effective.

I think that this is an analog video clamping/AGC issue. My guess is that the video proc adjustments on many capture cards occur AFTER the input clamping/AGC (and the damage) has already been done.

Adjusting the brigtness and contrast BEFORE the video reaches the capture card provides better results.

[amira]

Sorry what are "AGC" and Video Proc"?

[davideck]

Sorry what are "AGC" and Video Proc"?

"Video Proc" = Video Processor controls = Brightness / Contrast / Saturation / Hue / etc...

"AGC" = Automatic Gain Control

[The_Doman]

Did you try to use another VCR? (if available?)

Also try to see if the same problem is there if you only record a TUNER signal from the VCR. Just tune to a good and clear channel. Better also use some good LIVE preview program to test, like AMCAP.

[edDV]

Your problem is that your encoder thinks that your scenes with snow (or stars) are full of noise, so it can't encode it properly. You'll probably find the bps at these scenes to be MAX'ed out. Your problem when you "film the sun" are truly brightness issues. Try a different MPEG encoder.

It's a capture to 8 bits (256 levels) problem.

In the first post amira said
"When i playback my VHS on my VCR everything is fine."

No, it's an encoding issue. Just because there are only 8 bits doesn't mean that the full range of brightness isn't available. It just means that the "steps" between levels isn't as fine as a 10 bit system.

As for the "When I playback my VHS..." statement, it just means that the original doesn't have this problem.

To eliminate the card as a problem, just convert a few seconds of the area around the snow scene to an AVI format, then view this. If the same issue exists (and I doubt that it will), then I would get a better card.

It's not uncommon for scenes of dust, snow, rain or stars to give MPEG encoders fits.

We need a little overview of capture theory here.

Analog video ideally is 0.7v (1.0v with sync pulse) evenly distributed from black to white (e.g. 7.5-100IRE NTSC, 0-100IRE PAL).

This ideal signal will be captured to 8 bits (256 levels) with black at 16 and white at 235 (DV, DVD-MPeg2). The area under 16 and over 235 are safety areas for incorrect levels and transient overshoots.

Many oportunities exist for video distortion in the analog domain. In order to properly digitize the signal, the analog signal must first be restored to approximately the specs above before it hits the A/D. Othewise, you are just capturing part of the gray scale.

The simplest controls to to do this are "brightness", "contrast", and "color saturation" on low end computer capture cards. NTSC systems also have "Hue"

Now, amira said the video can be viewed OK from the VCR. He also implied that the picture above was the result after capture. If this is true, the problem was capture levels. If the picture looked OK after capture and then washed out during MPeg encoding, then the problem is the encoder.

From my experience, looking at amira's picture, I concluded that the video was not captured with proper black and white levels. If we could see the "before" image, we could see if this is due to no black reference in the picture or squashed whites due to camera exposure.

AGC is automatic gain control. AGC can work in different ways but in low end systems it just looks for a weighted peak signal level, and applies gain to put that peak near level 255 on the A/D. AGC can easily be fooled by whiteout scenes like those shown.

So, what to do
1. Capture a sample to see how the image after A/D compares to the original.
2. Make manual adjustments and repeat capture, repeat, repeat until you like the result.
3. Edit and encode the DVD

Higher end systems deal with this in 2 ways. First, a waveform monitor is used at the point before A/D to visually help steer adjustments for the correct black and white levels from a realtime IRE display. Second, most pro systems have gone to 10 bits (1024 levels 64=black, 940=white). This allows a looser capture with some adjustments possible in the digital domain with filters.

For example, wide safety margins below black and above white could be used to capture out of spec video, then digital filters could find and set correct black and white levels.

There are not enough quantization levels to do this effectively in 8 bit video and still produce a reasonable quality image, so the burden falls to analog processing before A/D.

[davideck]

Key issue to understand is that levels need to be correctly set before capture for 8 bit systems. There is not enough dynamic range to correct seriously hot or low white levels. The image shown above cannot be fixed with a digital filter. The data is not there.

It needs to be recaptured with the correct setting for white level.

edDV -

Changing the Quantization resolution from 8 bits to 10 bits does not provide an increase in Dynamic Range. The same analog video signal that exceeds 255 at 8 bits will exceed 1023 at 10 bits.

amira's problem is that his brightness/contrast controls do not affect the washed out bright scenes (see my earlier post). This is not a quantization resolution issue.