Opaque image from VHS

[torpidiy]

..

[TimA-C]

It would probably help if you could tell us which "cheap USB dongle" you're using and which version of Windows.

There may be some Procamp settings somewhere where you can tweak brightness, contrast, saturation, white point etc.

[torpidiy]

..

[Cornucopia]

For VHS+CheapUSBdongle, that's about right!

You can improve on this somewhat (tbc+proc amp, better deck w/ comb filtering, s-video line in, uncompressed capture), but you've STILL got VHS as your source. What did you expect, DVD quality? Blu-ray?

Let me guess, was this originally recorded in EP?

Scott

[jagabo]

I don't know what you mean by "shining" but that looks normal for a VHS capture. The blacks are a little too black and the brights could be brighter. The capture driver probably has proc amp settings you can adjust to take care of that.

[torpidiy]

..

[jagabo]

For VHS+CheapUSBdongle, that's about right!

Let me guess, was this originally recorded in EP?

Scott

No, actually it's in SP, and it's a "professional" tape - I mean I bought it, it's not a home recording.

VHS tape only has about 360 lines of luma resolution across the entire frame. And only about 40 lines of chroma resolution. You won't get much better resolution than you are getting now. Be sure to capture at 720x480 (NTSC) or 720x576 (PAL).

I'll answer your other question later. Gotta run right now.

[torpidiy]

..

[Cornucopia]

I'll leave jagabo to tell you, but it basically amounts to using AVISynth/Vdub (or similar) and it's video scope capabilities. Match YOUR bars to true REFERENCE bars (where NSTC Y black is 7.5% IRE is 16RGB and Y white is 100% IRE is RGB 235, with the color points falling in their hue & saturation windows), and thus you should be able to ASSUME that the picture is correct AS ENVISIONED BY THE ORIGINAL PRODUCER.

Gotta run also...

Scott

[lordsmurf]

Shining?
Opaque? (Of course video is opaque. It can't be transparent!)

Hard to understand what the issue is.

I almost wonder if this is a vague reference to some chroma noise not seen in a still.

[jagabo]

The blacks are a little too black and the brights could be brighter. The capture driver probably has proc amp settings you can adjust to take care of that.

Thanks, jagabo. But do you know how can I check if my settings are OK, provided I have the color bars (I suppose it's their function, right?).

First a massively useful tool: CSamp http://www.netreach.net/~gavin/gavsfreeware/csamp.htm. That lets you see the RGB values of whatever is on the screen. (It may not work in media player windows.) Press the "Press and hold" button, then while still holding the mouse button down move the mouse cursor around the screen. You'll the RGB values in CSamp's window change to reflect the value under the mouse cursor.

The colorbars have two features to help you get the levels right. In the lower right hand corner is the black level adjustment. In the black box there are two vertical bars. One slightly brighter than the black box, one slightly brighter. When displayed on an RGB monitor the majority of the black bar should be at RGB=0. The slightly lighter black bar should be at RGB=10 and should be slightly visible (it's visible in your sample image). The slightly darker black bar should not be visible and should also be RGB=0.

Near the lower left corner is a bright white box. That box should be at RGB=255.

In practice, shoot to get the black box just above 0 and the white box just below 255. If all three RGB values aren't the same use the green value as your guide.

A better way is to use the Histogram or VideoScope filters in AviSynth. These convert the brightness of the image into a graph where height of the graph equals the brightness of the image:

https://forum.videohelp.com/threads/340804-colorspace-conversation-elaboration?p=212156...=1#post2121568

But you'll have to learn a bit about how to use AviSynth. I don't know if you want to go that far.

Calibrating your capture card with a calibration tape is great -- if you're capturing recordings that were properly calibrated. Unfortunately, most VHS tapes you have from a camcorder of from off-air recordings won't have proper levels. You should adjust the settings for each VHS tape, even recording or shot.

[torpidiy]

..

[jagabo]

jagabo, thanks a lot! I will do it today.

Be careful. Use a program with known behavior. There are different ways of converting video YUV to RGB for display. Some media players will artificially pump up the brightness and contrast. The graphics card has proc amp settings that can change the way the video looks. I recommend you use VirtualDub to check your videos. Disable its DirectX output: Options -> Preferences -> Display... disable "Use DirectX for display panes".

[torpidiy]

..

[jagabo]

I think the bright end is a little too bright. The other white patch (below the blue bar) should be around 192. You may need to pump the saturation up a bit.

There's an awful lot of dot crawl in that image.

[torpidiy]

..

[jagabo]

The levels look good now. You need to get rid of that dot crawl. It's very hard eliminate after capture. Are you capturing with a composite or s-video cable? S-video should get rid of the dot crawl.

[torpidiy]

..

[jagabo]

Sure, it's easy to filter noise from a still picture. Now try it on some real world video with motion. Are you capturing NTSC or PAL? You should capture with the native frame size 720x480 NTSC, 720x576 PAL.

[torpidiy]

..

[torpidiy]

..

[torpidiy]

..

[Cornucopia]

You're going about this wrong. Colorbars are meant to work with YUV/YCbCr/YPbPr/YIQ levels, not RGB. Look up a tutorial on "setting up an image using a waveform monitor, vectorscope & colorbars".

Basically, it goes like this (for N.Am. NTSC):
1. On a Waveform monitor, set up Black to 7.5% (superBlack @ 0%)
2. Set up White to 75%, 80% or 100%, depending on which kind of bars those are. Peaks should NEVER go above 115%
3. On a Vectorscope, set your reference spots I & Q to fall within their boxes, both radially (Hue adjustment) and absolute value from 0 (Saturation adjustment).

Your bars should now be set correctly and your picture should look natural as intended (Assuming your monitor is ALREADY correctly calibrated).

Notice I said NOTHING about R, G, or B levels.

Scott

[jagabo]

Yes, adjusting colors is very difficult in RGB. It's best done in YUV. Here's an idealized vectorscope graph of the colorbars (lower right corner):



And from your last image:



The vectorscope from that image with the ideal locations marked:



The waveform monitor levels graph, ideal:



And from you last image:



Those were made with the VideoScope() filter in AviSynth.

[torpidiy]

..

[jagabo]

Is really that complicated to correct that?

Without the right equipment and softare, yes.

I think I will stick with the default levels and don't mess with it...

Just adjust the capture devices Hue and Saturation settings until you get something that looks about right.

And again, adjusting to a calibration tape is useless once it comes to real world VHS recordings.

[Cornucopia]

I don't quite agree with that, jagabo.
If the VHS tape(s) in question were originally recorded in one pass with Bars&Tone at the head or tail and the B&T stayed with the program regardless of transfer generation or processing, it should still be very effectual at helping return the captured image to the desired levels.

Of course, keeping those elements together is rare with consumer recordings...

Scott

[lordsmurf]

This whole thread is best summed up with two bits of advice:

(1) Get a better VCR
(2) Use s-video.