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  #1  
02-07-2018, 11:16 PM
Jtm732 Jtm732 is offline
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I know it may vary depending on my equipment. I am using Windows 10 64bit. My video source is VHS. I have figured out the default options (after having to install the device on another computer). My settings are set to the defaults and they are the following:

Brightness 128
Contrast 32
Hue 64
Saturation 32
Sharpness 2

I've read that sharpening VHS is a bad idea. So I am thinking sharpness should be 0. As far as brightness, it seems a little too bright, so I have lowered it to 100, but I am not sure if that is correct. My previous setup (same equipment) I had these settings:

Brightness 100
Contrast 34
Hue 74
Saturation 34
Sharpness 2

I'm honestly not sure how to properly calibrate these settings. I know I'd likely be calibrating them for my monitor and I am concerned exactly what settings I should use. I think the brightness should be lowered as I was told "the levels need to be lowered to 100 in VirtualDub when the time comes," but I really don't know which levels this meant. The brightness is definitely too high at 128 because black almost looks like gray. Should I focus on trying to set the brightness where I am setting black to be a black as possible without going too far? What is the best strategy for the other settings? Should I keep a little sharpness? Should I change my Hue/Contrast/Saturation at all?
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  #2  
02-07-2018, 11:34 PM
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lordsmurf lordsmurf is offline
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100 is correct. That's what "levels" meant when that was written.

Video does appear slightly darker on a computer than on a TV. And that's another reason you encode a copy for streaming, and leave the original unmolested in an interlaced archive version. If it's too bright on a computer, it's ll REALLY bright on TV.

Everything else was fine at default.

Sharpness at 2 or 0 makes almost no difference. This is an Empia chipset like the ATI 600 USB. The reasoning for the sharpness applied is that the chroma in Empia cards isn't quite as crisp as you see in some higher-end (are harder to install) cards. But for VHS, it's not really going to be a huge issue, because the resolution is lower than the chrominance anyway. I turn mine off, 0 setting.

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  #3  
02-07-2018, 11:54 PM
Jtm732 Jtm732 is offline
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Ok awesome. I'll set brightness to 100 and sharpness to 0 and call it a day. Thank you!
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02-08-2018, 05:28 AM
sanlyn sanlyn is offline
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Quote:
Originally Posted by Jtm732 View Post
I know it may vary depending on my equipment.
It will vary depending on your equipment, and it will vary slightly more depending on individual tapes.

Quote:
Originally Posted by Jtm732 View Post
I've read that sharpening VHS is a bad idea. So I am thinking sharpness should be 0
VHS is noisy, so sharpening noise is a bad idea. The sharpen default is 2. Do you know what 0 does? It decreases sharpness, reducing high frequencies and softening fine detail. Is that what you want? Blurring VHS is just as damaging as sharpening. If you think softening the incoming image will remove built-in, imbedded edge halos from bad tape mastering by the makers, it won't work -- do that kind of cleanup in post processing. Leave sharpness at the default unless you think your capture card itself is creating halos. If you reduce sharpness and the halos are still there, you've accomplished nothing except removing lots of detail from your signal. Post-processing software has far more sophisticated filtering available.

Quote:
Originally Posted by Jtm732 View Post
My previous setup (same equipment) I had these settings:
Brightness 100
Contrast 34
Hue 74
Saturation 34
Sharpness 2

I'm honestly not sure how to properly calibrate these settings.
Honestly, no one else is sure either. If you've been setting these by eye and expecting them to work for every input tape, then the numbers become meaningless. Is your monitor calibrated to sRGB or D6500 standards? How does your eyeball know when the darkest input values go lower than y=16 and cause crushed blacks, or when the brightest luminance values exceed y=235 and cause clipped brights?

The measured "y" values are luminance values. Use the VirtualDub capture histogram to set incoming levels to stay within the proper digital video range of y=16-235. "Y" levels will vary during play, but you don't want them to exceed 16-235, so play a short segment of tape to check how levels look in general, then start the capture after tweaking your settings. Note that black borders coming from the signal are usually belong at y=0 black, so temporarily crop the borders when taking your readings. Black borders would appear as a small sharp "spike" at the left=hand border of a histogram.

This has all been covered in the detailed VirtualDub capture settings guide:

Quote:

The luma levels histogram works only in preview mode and not during capture. The histogram displays a graphic view of input luma levels for checking if the input signal lies within the preferred video range of y=16-235. The histogram displays 16-235 data as blue data across the graphic horizontally: invalid values beyond 16-235 display as red in the side margins (left=darks, right=brights). Red indicates crushed darks and/or clipped whites during capture. If you see a flood of red at either side of the graph, the signal contains luma values that clip during capture. Some slight spillover is allowed now and then. Remember that black borders or bottom-border head-switching noise affects the histogram. These can be temporarily masked with the "Cropping..." dialog (see next post) during capture setup .

Histogram display (video extending beyond 16-235):



Histogram with levels adjust (slight spillover at left is usually OK):

Quote:
Originally Posted by Jtm732 View Post
Should I change my Hue/Contrast/Saturation at all?
I wouldn't, usually. Color correction is very klutzy and difficult in YUV, and you can't be very precise. You can only make very general settings between red and blue, green is not directly addressable. What would you do if you increased red and your tape later became too blue? Color values do change with VHS in some part of the spectrum or other, minute by minute and sometimes scene by scene. What would you do? Would you Keep stopping the capture and changing your settings minute by minute? That's an exercise in futility. Color correction is for post-processing.

Do you know what Contrast does? It controls the brightest values and specular highlights of the image, while brightness controls black levels. Adjusting one can slightly affect the other, so you often have to jockey back and forth between Brightness and Contrast to get things settled. It gets to be second nature after a brief trial period. Use the histogram -- that's why the histogram is there, it's not just a gimmick to decorate the interface.


A badly oversaturated signal causes color bleeding, especially with reds. This is a touchy subject. Changing saturation doesn't affect one color, it affects all colors. You could end up with pretty reds in an otherwise gray image. Does that sound OK? You have better control over this sort of thing in post processing, where you can modify the saturation of individual colors and also control bleeding and chroma shift.

If you're working with video using an uncalibrated monitor, you're making life really tough on yourself.

Last edited by sanlyn; 02-08-2018 at 06:02 AM.
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