VHS Restoration

[Asesinato]

I mean pro amp capturing settings... Maybe i should try and go back to default and then i can capture a bit for u there so you can see what ee start with

[sanlyn]

I mean pro amp capturing settings... Maybe i should try and go back to default and then i can capture a bit for u there so you can see what ee start with

I was about to suggest that. That way, we can see what the tape "really" looks like and advise what to do.

[Asesinato]

Here they are.. this is by default settings

[jagabo]

I mean pro amp capturing settings... Maybe i should try and go back to default and then i can capture a bit for u there so you can see what ee start with

Do you understand what a waveform graph is? You can create them with AviSynth's built in Histogram() or with the add on filter VideoScope().

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

A waveform graph is much more useful than true histograms (for levels anyway). Histogram()'s default is a waveform graph, not a histogram.

https://forum.videohelp.com/threads/340804-colorspace-conversation-elaboration?p=212154...=1#post2121545

[sanlyn]

Here they are.. this is by default settings
Capture2.avi (86.56 MB)
capture3.avi (69.28 MB)

Thanks for posting. Heavens, makes you choke a little, eh? One thing you've been doing correctly: you lowered saturation, which was a good move.It would take time to mount images of waveform graphs showing what actually happens when you de-saturate oversaturated colors, but that would take some time. In some cases you lowered saturation just a bit too much, in others not quite enough. Don't worry about correcting color balance: you have only a Tint control for that, and that type of control isn't suitable for the kind of corrections you need.

You have two basic groups of shots. Well, really, you have three groups:
1. Outdoor scenes
2. Dinner scenes while still daylight outside
3. Dinner/party scenes with darkness outside

If you lower saturation on the outdoor shots just slightly less than you have done earlier, I think you'll find that the overall color balance in those scenes is about right. Some minor corrections needed later, but with reduced saturation they look generally "correct".

You need to make two main adjustments for the dinner scenes. Lower saturation somewhat more than you have in earlier captures of those scenes. You will see some of the bad reddishness die down; things will still look warmish, but at least more natural. You'll also be able to see more stable detail in the brightest brights. Next, you need to lighten the darkest shadows and colors more than you have earlier. The dinner scenes during daytime are not as dark as the night-time scenes, but they're all pretty dark.

I don't think you need to raise the contrast (brights and high whites). When you lighten the dark end, however, check that your brightest whites aren't looking washed out or overly glowing. Brightness and contrast adjust opposite ends of the spectrum, but they also affect each other somewhat. You might have to fiddle to keep your darks lighter while keeping the brightest objects and highlights under control.

I'll get up a few captures to illustrate some of this, later.

You may not think your tapes are fading, but the color that's disappearing most is blue. Don't try to correct this during capture. The blue fading is non-linear and will require special treatment after capture; your proc amp's Tint or Hue control won't do it properly, and will probably make it look worse.

[sanlyn]

I assume the proc amp you use is your WinTV proc amp. Keep in mind that it has very basic controls, so you won't get a perfect image during capture. But you can get better ones that are more workable in post-ptocessing. The idea I want to illustrrate here is how to keep details and colors within a workable range. The "Hue" and "Sharpness" controls in WinTV won't help much, you should avoid Sharpness altogether (it will sharpen noise and artifacts and cause posterization, which you don't want)). Maybe I can also show why the Hue control is of little help.

The posted AVI's were adjusted using Avisynth Saturation, Bright, and COntrast controls that should work in a way that is similar to the same controls in your WinTV. The captures were made in VirtualDub; Photoshop Pro was used to resize only, no other processing involved. Your captures are in YUY2, which is correct, but in order to accurately view your AVI in VirtualDub you should use an Avisynth script to convert properly to RGB. To open the AVI in VirtualDub, crete a script called "Avi_Open.avs", save it. Instead of opening the AVI in VirtualDub, open the avs script:

AviSource("path to your AVI\filename.avi")   # <- ENTER PATH AND FILE NAME HERE, IN QUOTES
ConvertToRGB24(matrix="Rec601",interlaced=true)

This demo uses RGB histograms in VirtualDub. In this case they are more intuitive to show what I want to demonstrate. The VirtualDub ColorTools plugins has other graph forms that give the same information, including a waveform and vectorscops, but they arrange the information differently.

This is a slightly reduced image from frame 50 of Capture2. This is the unmodified video, as captured:


The image looks too dark, appears over-saturated, and too red. But it's really more complicated than that. Trying to reduce red with the Hue control won't work properly, nor will trying to increase or decrease Blue or Green. Look at the histogram on the right, which tells you why. The top portion is the luma level, below it are Red, Green, and Blue. The "bars" at each side of the histogram don't mean that much particularly, but the one on the left usually indicates "RGB 16", the one on the left indicates "RGB 235". The left-hand side of the histogram is the amount of dark dark colors, the right-hand side is the brightest colors. The exact middle of the histogram represents RGB 128, which is the midpoint between the full range of RGB-0 to RGB-255.

Note how the luma component (white) ends abruptly on the left at the RGB 16 border, but the colors below it extend to the left beyond that point. The white area indicates that some sort of luma limiting (clipping or cutoff) is occurring somewhere. Maybe it's on the original tape, maybe the player, maybe the WinTV, but it's there so we have to work with it.

Now, note the horizontal shape of the 4 color graphs. They are all very flat, lying low and close to the 4 horizontal borders. The white luma component stretches only 75% of the way across the histogram. Red is stretched farther across, end to end, and climbing up the left wall (indicates clipping of dark red). Green and Blue are clipped at the left as well; green stretches about 80% of the way across, blue is a mere 40% to 50% of the way across the chart. This is aged, oxidized, poorly stored tape: the colors are fading, but they're fading unevenly. The color loss is greater with bright green, but it's severe with mid to bright blue. A "Hue" control can't fix this. You will have to fix it in software, after capture.

Here is the same frame. All that was done here was to reduce Saturation. No other change was made:



The image has changed, and so has the histogram. Reducing saturation "contracts" the colors, or draws them in from both ends toward the center. The first thing you notice is that color seems more natural. You see less streaking and color bleed (it's still there, but it's not "stretched-out" the way it was before, so is less prominent). You are starting to see a little more detail in the darks, and brights don't look blown-out. There are now higher peaks and ridges across the middle of the histogram, so you have actually increased midtone resolution. Also note that the colors that were crushed against the left-hand side are less crushed now. The colors of the flagpole, the houses in the background, and groom's suit look more normal.

This was a rather sizeable reduction in saturation. I don't know what the scale of numbers looks like on your WinTV control, but my reduction was 45% down from normal. With these outdoor shots you could almost get away with this adjustment alone. But there's still a problem with the darkest shadows being a little blocked up (look at the shrubs, the lady's dress, the blackish shadows in the man's suit).

Using the same saturation reduction as above, here I made only a very slight increase in "Bright" to raise the black levels. On my brightness controls scale, this was barely an increase of 3 percent:



Shadows are delineated more clearly and the posterizing or blocked-up effect looks better. The image does look a bit thin and less crisp. Don't attribute that entirely to the raised blacks: the real problem is in the low end of the gamma curve and the "gain" element of the colors and luma. You have no gamma or separate gain adjustment in your proc amp. That can be fixed later.

Notice that the left end of each of the three colors is now drawn closer into the histogram, indicating that we have at least stopped most of the hard clipping of the three colors. This is a much more workable image.

You can also play with Bright and Contrast a bit, but be careful. The two controls do interact somewhat, so watch your shadows and highlights carefully. In particular, you want to avoid pushing colors out of bounds at either side of the histogram. Below, I've made less than a 2% to 3% adjustment in brightness and contrast, with saturation staying the same as before:



No, you don't yet have a "perfect" captured image. Not with this damaged tape! You don't have the kind of proc amp controls you need to get perfection. For a mere 4000 or 5000 Euros, you could probably get a proc amp that can do it all. But later, after capture, you can tweak levels and work with gain, gamma and color in software -- for free. But at least you have an image you can work with.

These adjustments also made those dark angular lines brighte and more pale. They are less obvious and will likely be much easier to filter away.

Later today I'll work up a demo on the indoor shots of the dinner and party. Those are really a problem.

[sanlyn]

Oh, well. You seem to have different problems in different areas of your tape. Even that diagonal herringbone changes shape and frequency now and then. Thru thesee captures and the others, however, the same uneven color fading is present. In the interior scenes it seems to look worse because of the action of the camera's auto-exposure; it really kills dark detail every time something bright enters the picture.

Your best bet with the interior shots in this video is to raise blacks levels a small amount, and use some small adjustments in contrast to keep things like bright objects and highlights from "glowing" onscreen. There are many ways to improve those scenes, but your proc amp won't help much except in terms of keeping the scenes from looking too thick and "black" in the shadows. Don't worry that really dark areas might occasionally look a bit gray instead of black; that can be fixed, too. Lowering saturation in those scenes doesn't help, and could possibly hinder. The type of lighting and the auto0-exposure is keeping your color range severely limited anyway. If you want to take up the lower-saturation idea, don't lower it more than 10%, or you might kill off what little bit of the brighter blues are in those shots.

I echo jagabo's suggestion that you disable auto-gain on audio. The small amount of sound I heard earlier seemed pumped to distortion.

[Asesinato]

I see what you mean, but what then in the dark scenes, to make them look good we have to make the bright scenes look bad?

[sanlyn]

I see what you mean, but what then in the dark scenes, to make them look good we have to make the bright scenes look bad?

No way. Remember, these are first-step captures, not the finished product. Did you think the dinner scene I posted earlier looked like your capture? There was plenty of post-processing along the way.

Record the brighter scenes into one file. Then adjust settings and keep the darker interiors in another file. They can easily be joined later. The main idea during capture is to keep from capturing "bad" detail that you can't get back. There are many ways to re-adjust and fine-tune later.

Capture3 (original, frame 139). The histogram shows so little color, the only color seen is red. You can't even see black (that's red, too). Luma doesn't go below RGB 16, just as before, but colors are off the scale to the left. In the image you can see "black voids": the big lady on the left, lost detail behind her, the black blob in the hair of the dancing girl and no detail in her slacks, and below-black areas in the figures on the right. Detail being crushed everywhere. The bright lights are well within the RGB 235-255 range, so raising contrast isn't something you want to do with these shots.



Capture3, saturation down 45%, blacks raised about twice as high as before, to 5 or 6% on my 255-point scale. There are still a few black "blobs" and black "spots" here, but much better detail. Again, I'd avoid raising contrast in these shots; the lights are already bright enough and a few highlights are on the verge of burning up - so leave conbtarst as-is. The lighting in these shots is going to be somewhat warmer than daylight, but in post-processing you'd still need to tweak a few specific regions of blue and green, but not over the whole image. For the rest, we'll have to work with gain and gamma controls later. The histrogram shapes and the image itself shows clipping in-camera. You can't fix that during capture. Deblock, smoothing, and other plugins can help. Don't try to change the color balance during capture; your proc amp can't do it properly. Wait until post-processing.



Belkow, is frame 185 original (top image), then after the same settings (bottom image). Does it look darker than the other frames in this scene? You bet it does. You can thank the camera's auto-exposure for effects like this. There's no fix for it The best you can do is to use the same capture settings as for the other frames to prevent total loss of detail, then tweak in VirtualDuib.




If you can capture to just save some of this detail and get a decent histogram, you'll have something to work with. If you'd like to get a better proc amp that has more controls than your basic WinTV card, you have to spend some money. Lots of it. Here is a very good quality proc amp, sold and used in the U.S. and worldwide: SignVideo PA-100 -- this is one of the more "basic" proc amps used by hobbyists and pros alike.

Even then, you would still have more work to do after capture.

You're also using an uncalibrated monitor, which doesn't help the view at your end.

[sanlyn]

I see what you mean, but what then in the dark scenes, to make them look good we have to make the bright scenes look bad?

1. The idea is, we start with a really damaged tape:


2. Get a better capture with level corrections and a decent histogram, using a very basic proc amp:


3. Then post-process:

[Attachment 12115 - Click to enlarge]

When you try setting white points, black points, and neutral points for color, you get some surprises with this scene. Among the surprises are:

a) Just behind the camera, up near the ceiling and off to the left, are two small colored lamps. One is yellow. The one farthest away is pale pink.

b) The girl in the white blouse with her back to us isn't a redhead. As long as she's dancing in the corner seen here, her blouse will never be pure white. It will have either a yellow or a pink tint.

[Asesinato]

Hey mate ive tried applying what you said

The bright are:

Sat is from 128 to 58
Contract is from 128 to 131

[Asesinato]

Dark Area:

Sat is again from 128 to 58
and contracts is from 128 to 120

Did it understand you correctly?

[jagabo]

No, you're not understanding anything. The darks are too dark and the brights not bright enough in both files.

And you don't have to upload 65 MB files for quick levels tests.

[sanlyn]

IMO, from the previous no-settings captures the highest brights are OK on the source tape. The brightest of them are around RGB 220, which is quite workable. Better than having them blown away, which was a big problem on earlier captures. The latest captures tell me what the "Contrast" control on his WinTV is doing: it darkens the darks and raises the brights. So I wouldn't even touch the Contrast control, it does more harm than good.

Saturation settings were OK, but it was brightness that needed to be increased, not contrast. On the source tape the image is quite dim, so the losses appear to me to be mostly in the dark and lower-midtone area. One could always pump up the brights later in software, but no way to retrieve darker detail if the WinTV contrast control is drowning the darks at the same time that it nearly blows away highlights. I'd say increase the brightness - about 5% in the daylight shots and 10% in the indoor shots. That way, some of the lower midtones and whatnot might look a little gray in the capture, but that's better than having them crushed. The darks and mids can always be adjusted later, but not if they're lost in capture.

RE: that 10% recommended brightness increase in the interior scenes: look at the previous Capture3. When the camera's auto-exposure dims the picture there's no dark detail at all. True, in those brief dark seconds you can't get much low-level data (it will just have to look dark for that brief time), but at least one could save some midtone data.

I'd say leave Contrast alone. As long as brights are intact, they can be worked with. But once the lows are gone, it's all over.

[Asesinato]

Bright test

Sat as before and 5 % brigtness, contacts default

[Asesinato]

Dark test

Sat as before and 10 % brigtness, contacts default

[jagabo]

Still crushed at the bottom (I only looked at the dark video). Bring the blacks up until they are OBVIOUSLY NOT BLACK by looking at them. That will tell us if the black crush is happening during the cap or before. And upload the same section of video each time so it's much easier to compare. And the word is CONTRAST, not contacts.

[Asesinato]

like that?

[sanlyn]

Wow, you really need to get some level of calibration into your PC monitor. That aside, I see here that the brightest brights are just on the border of being about right, or at least workable. I'm not afraid to say, the auto-exposure on that camera is your worst enemy here. I realize it's making it's very difficult for you. Auto exposure should be prohibited on amateur cameras, except for use in bright daylight. But that's not your fault . I hate auto exposure cameras, I always turn it off if I can and set exposure myself.

Anyway, it's too bright at this point, but the detail is all there (the detail that the camera allowed onto the video, anyway). Without the aid of a histogram when you set up capture, I know it's difficult to judge these things. I don't know what the brightness adjustment scale on your proc amp looks like in terms of the actual numbers it uses. Can you tell us this? What is the default brightness value without any changes made, and what is the brightness setting that you used for the last capture?

[jagabo]

like that?

Yes, finally! From that and the previous cap we can see that there is only a little real detail below the Y=16 line in the older cap. Here is a scope view of the two caps:



But most of that "detail" is oversharpening halos. If the VHS deck has an adjustable sharpness setting try turning it down. Otherwise, I would settle for capturing with the black level around half way between the older cap and this latest one. That way you'll be sure to have enough to work with near the bottom of the luma scale.

[jagabo]

Also from the last two dark caps I can see that the diagonal line noise is not the same each time the tape is played. This implies it is not recorded on the tape but something about playback. You could greatly reduce it by making several caps then averaging them together.

A frame from the earlier dark cap:


The same frame averaged with the new lighter cap (darkened to about the same brightness):


Even just averaging two caps together has greatly reduced the diagonal lines. Averaging four caps would probably be enough.

The script I used used:

v1=AviSource("capture2(1).avi").Trim(97,0)
v2=AviSource("capture2(2).avi").ColorYUV(off_y=-24)
Merge(v1,v2)

Four caps would be averaged by

 Merge(Merge(v1, v2), Merge (V3, v4))

Note: I made no attempt to adjust the levels (other than to make the levels of the two clips ~match) or anything else. I was just attempting to show how merging averaging two clips together would reduce the noise.

[sanlyn]

Deleted my redundant commentss. Jagabo beat me to it. Again.

[Asesinato]

I can easy make 4 caps if that will help, but wount it be realy hard to make sure the recording starts add the exactly the same frame? Els id suppose the the 4 caps merged together will give everything a kind off ghost effect???

San > ill post the values you wont in 2 min

[jagabo]

I can easy make 4 caps if that will help, but wount it be realy hard to make sure the recording starts add the exactly the same frame?

You just use Trim() (like I did in the sample script) to align the videos. Of course, it's best to get caps without dropped or duplicate frames. So it's best to work in short segments. Don't expect to get perfect two hour caps every time.

[Asesinato]

Code:
v1=AviSource("capture2(1).avi").Trim(97,0)
v2=AviSource("capture2(2).avi").ColorYUV(off_y=-24)
v3=AviSource("capture2(3).avi").Trim(97,0)
v4=AviSource("capture2(4).avi").ColorYUV(off_y=-24)
Merge(v1,v2), Merge(v3,v4))

Btw: Will the code then look like this?

[Asesinato]

Okay... So small 1 hour caps and merge together and when i have 3 1 hours merged videoes then i put then all together in one big file?

[Asesinato]

San > im almost home and then all post those values for u

[Asesinato]

Contrast default 128
Brightness default 0

dark test

Sat as before and 10 % brigtness, contacts default

There brightness was as 10


And the last cap that was realy bright, brightness was at 55

[sanlyn]

Thanks for checking that. Yes, 55 overdoes it. I take your numbers to mean that your brightness scale is 0 at default and up to 100 at the brightest. If you used 55 for those last dark interior shots, set brightness at 25.

For those outdoor shots in front of the church, you don't need that much boost. For those shots, try brightness at 10 or 12.

The saturation level you used for these last captures is about right.

[jagabo]

Code:
v1=AviSource("capture2(1).avi").Trim(97,0)
v2=AviSource("capture2(2).avi").ColorYUV(off_y=-24)
v3=AviSource("capture2(3).avi").Trim(97,0)
v4=AviSource("capture2(4).avi").ColorYUV(off_y=-24)
Merge(v1,v2), Merge(v3,v4))

Btw: Will the code then look like this?

Yes, but the Trim() will be different on each clip, and the ColorYUV() won't be necessary.

Okay... So small 1 hour caps and merge together and when i have 3 1 hours merged videoes then i put then all together in one big file?

Something like that. You might even break it down into 10 or 15 minute clips. Depending on how reliable your caps are.