Calibrating luminance levels/color for capture from VHS

[sanlyn]

I don't get an error message opening your video in VirtualDub, but I get a garbled image. I don't know what jagabo used to work with your video in AviSynth, but my PC codecs don't work with your file (they play OK in VLC player). Jagabo and and some other members are codec experts here, they'll have the answer. Curious about that myself. I've always captured with huffyuv/YUY2 or uncompressed RGB.

In any case, the usual syntax for VHS-SD is:
AssumeTFF().ConvertToRGB32(matrix="Rec601",interla ced=true)

Jagabo will have to tell us what he used to work with that video in AviSYnth. I see interlace artifacts in the cap he posted. IF your video is HD, I'd need to crank up another PC from my basement to work with it.

[jagabo]

I didn't deinterlace, just picked a frame without too much motion. Here's the script I used to adjust the luma levels and display the waveform graph:

AviSource("Love and Painasd.avi", pixel_type="YUY2")
ColorYUV(gain_y=15,off_y=-12)
VideoScope("bottom")

It was necessary to use pixel_type="YUY2" because the image height was an odd value.

You'll need the VideoScope filter if you want to use it. You can get it here:
http://avisynth.org/warpenterprises/

AviSynth has a built in waveform filter, Histogram():
http://avisynth.org/mediawiki/Histogram

It builds the histogram sideways though. You can get a horizontal histogram by rotating the image:

AviSource("Love and Painasd.avi", pixel_type="YUY2")
ColorYUV(gain_y=15,off_y=-12)
Addborders(0,0,0,1)
TurnRight().Histogram().Turnleft()

Histogram also clearly shows the illegal luma value areas.


AddBorders() was used to pad the frame size to an even height. YUY2 requires even width so rotating the image 90 degrees required the frame to have an even height.

You may also want to look into denoising with something like McTemporalDenoise(), a dehalo filter to reduce the VHS oversharpening halos, and a sharpening filter. And if you're really serious, get an SVHS deck with a line time base corrector to get rid of all the horizontal jitter before capturing!

[Cherbette]

@jagabo how do I convert to RGB using Avisynth...or better yet what is the code? That way I can use Color Tools in VirtualDub until I can further educate myself on Avisynth. Here's the screen that pops up when I use the script sanlyn provided...Thanks again fellas for all the helpful feedback


AviSource("C:\Documents and Settings\Administrator\Desktop\Love and Pain.avi")
AssumeTFF().ConvertToRGB32(matrix="Rec601",interla ced=true)


Also are there software available with Time Base Correction?? I see that Avisynth has some sort of filter for this...

[jagabo]

You can open your video directly in VirtualDub. It will convert to RGB with a rec.601 matrix for filtering. If your video had blacker-than-blacks or whiter-than-whites that would cause the regions to be crushed. But your video doesn't have those.

I'm not sure how you're getting those AviSynth messages. You should start with just:

AviSource("C:\Documents and Settings\Administrator\Desktop\Love and Pain.avi")

If the AVS file is in the same folder as the AVI file you don't need the full path name:

AviSource("Love and Pain.avi")

Also try my version:

AviSource("Love and Pain.avi", pixel_type="YUY2")

and

AviSource("Love and Pain.avi", pixel_type="RGB")

As noted earlier, some codecs don't like odd frame sizes. I would go back to the original 720x480 until you've verified that the odd frame size isn't your problem. What HuffYUV decoder are you using? The HuffYUV codec? ffdshow? Something else?

[sanlyn]

Also are there software available with Time Base Correction?? I see that Avisynth has some sort of filter for this...

There is a software "TBC" plugin for AviSYnth, but it doesn't work. We all hope the developer gets it going one day. He's attempting the impossible. But you never know...

There are 2 types of TBC. Frame-level (aka full frame) TBCs correct frame timing and audio sync. Two popular models are the AVT-8710 and the TBC-100 (or TBC-1000). They don't do anything to correct such line-level problems as crooked verticals, tearing, some types of chroma smear and motion artifacts, etc. Line-level TBC's are usually a mainstay for VHS. They correct line-by-line flow rate in each frame. External line TBC's come as part of expensive studio-grade TBC units, or as cheaper versions in a few high-end VCR's that aren't made anymore.

There's no way a "software" TBC can correct these timing problems; they have to be fixed during initial playback. One solution used by many who can't find old TBC-equipped VCR's is to get a Panasonic or Toshiba DVD recorder and use their built-in quasi-TBC's as pass-thru devices. You plug your source into the DVD recorder's input (for Panasonics, use Line 1 only), then connect the recorder's output (s-video preferred) to your capture device. Works fine. I've been using it for years.

[jagabo]

Line TBC examples:
https://forum.videohelp.com/threads/230650-Confused-Why-a-VCR-with-TBC-if-separate-TBC-needed-anyway
https://forum.videohelp.com/threads/319420-Who-uses-a-DVD-recorder-as-a-line-TBC-and-wh...=1#post1983288

[sanlyn]

Line TBC examples:
https://forum.videohelp.com/threads/230650-Confused-Why-a-VCR-with-TBC-if-separate-TBC-needed-anyway
https://forum.videohelp.com/threads/319420-Who-uses-a-DVD-recorder-as-a-line-TBC-and-wh...=1#post1983288

Thanks, jagabo, I meant to refer the OP to those posts, but couldn't fine 'em (again!).

Still having problems with UYVY. I get a garbled image in every player and app except VLC player. Can't use this video in AviSynth or VirtualDub, as -is. I'll keep playing with image size, but "pixel type" didn't change results. If you were able to get a clean image, then something's different with our setups -- and as usual, yours is probably correct.

I didn't think AviSynth "convert" would work with UYVY.

[sanlyn]

You can open your video directly in VirtualDub. It will convert to RGB with a rec.601 matrix for filtering. If your video had blacker-than-blacks or whiter-than-whites that would cause the regions to be crushed. But your video doesn't have those.

I'm not sure how you're getting those AviSynth messages. You should start with just:

AviSource("C:\Documents and Settings\Administrator\Desktop\Love and Pain.avi")

If the AVS file is in the same folder as the AVI file you don't need the full path name:

AviSource("Love and Pain.avi")

Also try my version:

AviSource("Love and Pain.avi", pixel_type="YUY2")

and

AviSource("Love and Pain.avi", pixel_type="RGB")

As noted earlier, some codecs don't like odd frame sizes. I would go back to the original 720x480 until you've verified that the odd frame size isn't your problem. What HuffYUV decoder are you using? The HuffYUV codec? ffdshow? Something else?

I tried those tips, other tips, some doom9 suggestions for codec download. All scripts, as well as just VirtualDub's plain old "Open video file") gives me exactly the same results:


[Attachment 8715 - Click to enlarge]

I used huff/UYVY some time back, no problems. However, I didn't capture with DirectSHow. I captured with Windows WDM (vfW). I noted in previous post that the OP has WDM as an option. Couldn't he capture with that?

[jagabo]

I tried those tips, other tips, some doom9 suggestions for codec download. All scripts, as well as just VirtualDub's plain old "Open video file" gives me exactly the same results:


[Attachment 8715 - Click to enlarge]

I'm using ffdshow as my HFYU decoder. Maybe that will help?

[sanlyn]

Hm. Last time I installed ffdshow was right after XP Service Pack 3. I could no longer play huffyuv of either RGB or any YUV in any media player, only in VirtualDub. I tried removing SP3, reinstalling ATI's 2006 WDM divers, etc.. No go. So I wiped out XP-SP3 with a DriveImage backup made just before installing SP3. Everything works again (except for this video). I never have problems with VFW, only with DirectShow. I'll make another backup now that everything's working, then install ffdshow again later tonite or tomorrow. Maybe I'm not setting up ffdshow correctly. Thanks, jagabo.

[Cherbette]

WDM does work for capture with my device...would that be a better option? If I'm not mistaken, I think capturing with that option disables something...I can't remember if it's the proc amp controls or what...I'll have to check

[jagabo]

Use whichever capture driver works better (least dropped frames and A/V sync problems) and gives the best options.

[sanlyn]

Use whichever capture driver works better (least dropped frames and A/V sync problems) and gives the best options.

Yep

[sanlyn]

WDM does work for capture with my device...would that be a better option? If I'm not mistaken, I think capturing with that option disables something...I can't remember if it's the proc amp controls or what...I'll have to check

WDM would likely disable the proc amp, but you could try it. Using the DC500 controls amounts to a "software proc amp", but I notice earlier you're applying some VirtualDub color filters during capture anyway -- btw, avoid denoisers during capture, which will really slow you down during capture. You might be dissatisfied with the results and have to capture again. Whatever you apply during capture will be difficult to change later.

There's no substitute for an external proc amp. They do most of what you're looking for, and SignVideo's PA-1 is a pro-grade, popular product that gives cleaner results. Definitely not in the same price range as the DC500, but I couldn't live without mine.

Which reminds me, jagabo, using VirtualDub filters during capture: don't those filters work in RGB-only? I wonder if VDub has to convert to RGB, then back to the capture colorspace? It seems that would create interlace and colorspace issues.

[jagabo]

Which reminds me, jagabo, using VirtualDub filters during capture: don't those filters work in RGB-only? I wonder if VDub has to convert to RGB, then back to the capture colorspace? It seems that would create interlace and colorspace issues.

VirtaulDub's filters work in RGB (mostly; Brightness/Contrast can work in YUV) but the capture card's proc amp should work in YUV and probably in 10 or 12 bit (per channel) color and while the video is still oversampled (1440 samples per line?).

[sanlyn]

Thanks. Then other filters (like color, etc., probably not Crop) might have some other effects. I never filter during capture anyway except with external proc amps, so I'm, uh, guessing about other filters.

BTW, I made another backup and installed ffdshow. Sure enough, that's the culprit. No media player could play huffyuv compressed files, except VirtualDub/AviSynth. I even told ffdshow to leave huffyuv alone during setup. Fortunately, this time it was fixed by uninstalling ffdshow (didn't have to restore from backup). I have no idea why this happens, but I do know that for years I didn't have ffdshow installed when those huffyuv captures were made with WDM/VFW. I've always had problems with DirectShow. And never installed ATI's MMC after 2002, it replaced many standard YUV codecs (including msyuv.dll) with its own, making caps unplayable on any PC that didn't have MMC installed.

Will figure that out later. Back to work.

ffdshow didn't help with the video in question. Shucks. Too many mysteries for one day. I'm brewing another Keurig K-Kup before proceeding...

[jagabo]

Then other filters (like color, etc., probably not Crop) might have some other effects.

You can see which colorspace each filter acts in by selecting the "Show Image Formats" option in the filter list dialog.

I never filter during capture anyway

Me either.

BTW, I made another backup and installed ffdshow. Sure enough, that's the culprit. No media player could play huffyuv compressed files, except VirtualDub/AviSynth.

Weird. I have no problems with ffdshow on my XP and Win7 systems. I did have problems with HuffYUV and 2.1.1 and 2.2.0. Maybe your problem is related to that? Ie, maybe HuffYUV 2.1.1 and ffdshow are compatible but you have HuffYUV 2.2.0 encoded files that ffdshow doesn't like? I don't know for sure that this is an issue, just guessing from problems I've seen in the past.

VirtualDub and AviSynth's AviSource() both use VFW codecs. Media players and AviSynth's DirectShowSource() will use DirectShow codecs. Since VirtualDub was still working your problem was probably related to that. ffdshow has separate configurations for each.

[sanlyn]

Prob'ly right, jagabo. I am using huff 2.2.1, always have. Solving this would be a great way to burn up a weekend (or more). But ultimately all my valued caps end up getting cut into 4-GB uncompressed RGB32 AVI's and burned to disc. Good way to use all those emptied 100-disc plastic spools!

[Cherbette]

You may also want to look into denoising with something like McTemporalDenoise(), a dehalo filter to reduce the VHS oversharpening halos, and a sharpening filter. And if you're really serious, get an SVHS deck with a line time base corrector to get rid of all the horizontal jitter before capturing!

What combination of filters would you guys recommend for VirtualDub that are comparable to the ones listed above for Avisynth?

[jagabo]

They're not as sophisticated as McTemporalDenoise() but you can try 2D Cleaner, Temporal Cleaner, and Temporal Smoother, MSmoother, VHS. There's also the commercial product, Neat Video.

For sharpening there's the internal Sharpen filter, WarpSharp, MSharpen,

I don't think there's a dehalo filter for VirtualDub.

http://www.virtualdub.org/virtualdub_filters.html
http://neuron2.net/mine.html
http://neuron2.net/hosted.html

[Cherbette]

Thanks again for the tips. I would have been getting absolutely nowhere without the help I've been provided with here.

Here's another (shorter) clip which is 7 seconds long about 50mb and the quality of this clip is nowhere near the one previously posted...

http://www.mediafire.com/?ks4hhaai49ema9w

I don't even know where to start with all the issues this one has...I think I've calibrated the brightness/contrast properly with the Histogram but it's hard to tell because I think the source is kind of "bleached" out.

[Cherbette]

On a side note...I didn't have any problems before but now when I open Virtual Dub and go to Capture AVI and set the Video to Preview w/Histogram the preview screen looks very green and when I try to adjust the proc amp levels VirtualDub freezes...it seems to be taking up tons of CPU which it wasn't doing before either...I don't know what's going on lol

[jagabo]

That's a really sad multi generation VHS copy. The levels on that recording are a little tricky. The VHS sharpening filters have caused overshoots. So some areas are artificially darker than they should be. Like Cher's hair. I would go ahead and let those area fall below IRE=0 (Y=16) in order to get the contrast better on the rest of the picture.

AviSource("Cher2.avi")
ColorYUV(gain_y=10, gamma_y=-40, off_y=-10, cont_u=50, cont_v=50, off_u=2)
BilinearResize(180,480).BicubicResize(720,480)
MergeChroma(last,McTemporalDenoise(last, settings="very high", interlaced=true))

Before:


After:


What you can't see in the still shot is that the chroma is much more stable. Rather than flickering between green and red casts it stays more constant.

I used a cheap trick to remove some of the VHS haloing. Resizing down, then back up. That leaves the video a bit fuzzy but removes a lot of the halos. If it's too soft for you use a larger size in the first resize. You'll get less effective dehaling though.

You might go a little further with the levels adjustments. Look at a wider variety of shots.

I used MergeChroma() to retain the luma noise while applying a very strong noise filter to the chroma noise. I think there's a way to tell McTemporalDenoise() to denoise only the chroma. Or apply different amounts of filtering to the luma and chroma. If so, you could do that instead.

I don't usually work with video this bad. Maybe someone else has some better ideas.

[sanlyn]

Looks good, jagabo. Too bad none of the 3 PC's I tried today could read these clips in VirtualDub (plays in VLC Player, only -- which uses ffmpeg, doesn't it?). One of those PC's is a cheapo HP that never saw huffyuv, WDM, or anything more esoteric than AOL. I installed ffdshow on it and AviSynth/VirtualDub, played a bunch of AVI's made with various compressors, etc., but still couldn 't play these videos.

Anyway, your result with Cher looks about as proper as it ever will, short of spending $50,000-plus on software and hardware.

[sanlyn]

Hm. My suspicions about ffdshow/huffyuv after reading doom9 and some newsgroups are apparently valid: ffdshow/huffyuv and huffyuv 2.1.1 are not the same engine. With ffdshow installed, I have to disable ffdshow's huffyuv to see my 2.1.1 captures; I have to enable ffdshow's own schizo huffyuv to decode these videos. This means that for any of my last 9 years of AVI captures, I have to effectively "turn off" ffdshow.

More coffee, please. It's taking me too long to figure out simple stuff like this.

[Cherbette]

May I ask what size you used when you resized down and then back up? I agree with sanlyn that those results are about as good as it'll get...unfortunately this clip is 26 or 27 years old and is at least 2 or 3 generations copied and I doubt I can find better....so I appreciate the tips

[jagabo]

May I ask what size you used when you resized down and then back up?

It's in the script:

BilinearResize(180,480).BicubicResize(720,480)

[Cherbette]

May I ask what size you used when you resized down and then back up?

It's in the script:

BilinearResize(180,480).BicubicResize(720,480)

My apologies...somehow I completely overlooked the script at the top of your post...thank ya.

I can't seem to find the MCtemporaldenoise filter for avisynth for download anywhere...

[sanlyn]

I managed a little work on your AVI d8d0stac9k64z4h (post #19 18Sep2011, 185MB). Your color and luma levels looked pretty good. I didn't do any resizing, it's too destructive with VHS: I added black borders to make the video 704x480 (the preferred DVD frame size for 4:3 sources. 720x480 cuts off pixels).

Lots of problems. Rather noisy image,VHS grain and streaking. The noise is obvious in post (A) below, an MPEG of the RGB-converted video with no denoising or color work. Noise is easy to see in dark areas and edges of the spotlight on the back wall.
NTSC MPEG2, no audio, 704x480 (640x480 display), 21-MB
http://dc254.4shared.com/download/dLzxk4W2/A_LovePain_NoiseB.mpg

These caps from the original upload show one of the problems. Bad tape tracking. Most of this could be fixed with a line TBC. The tape is physically distorted, not riding properly on the heads, with severe variations in line output rate. The cap below (reduced to 75% original size) is frame 304. The cap below it is a blow-up of the distortion seen in many frames. Cher's face is rather "bent". In the blowup you can also see the noise we're dealing with.


[Attachment 8738 - Click to enlarge]

[Attachment 8739 - Click to enlarge]

Another problem is frequent discoloration, and "flashes" of off-color. The image below is frame 398. The red background behind Cher has gone green. The cap below this frame shows frames 398 (green) and 457 (pink). The bad colors appear mostly in even fields, not so much in odd fields, and often both. If you use SeparateFields and then StackHorizontal(even,odd) to see the fields next to each other, you'll see that any chroma cleaning will have to work on separate fields.


[Attachment 8740 - Click to enlarge]

[Attachment 8741 - Click to enlarge]

The MPEG below is the video after denoising with NeatVideo. I did very little color work, as the original cap looked pretty good. No sharpening. Even though I turned NeatVideo's filters down to considerably below midrange, I could have turned them down lower and got similar results. VSH looks a little weird with too much noise removed.
NTSC MPEG2, no audio, 704x480 (640x480 display) , 21-MB
http://dc273.4shared.com/download/Z4No9VUZ/B_LovePain_NVLP03B.mpg

I tried a little work in YUY2 with an AviSynth filter (mvtools), trying to clean up some of the distorted frames. In some cases mvtools helped, in others it didn't help much, and in some places it looks a bit worse (you can't interpolatge new frames from other bad frames. All you get is "new" bad frames.) In some spots you have 4, 5, or 6 bad frames in a row. A line TBC would have helped enormously. MvTools could have been used in the original YUV stage before going to RGB, probably without the slight color shift I noticed from RGB->YUY2->RGB. Unfortunately, you have to denoise a video before resizing (resizers sharpen everything, including noise) or trying to repair bad frames.
NTSC MPEG2, no audio, 704x480 (640x480 display) , 21-MB
http://dc390.4shared.com/download/eWyIEOZ7/C_LovePain_NVLP03Bmv.mpg

Some of these bad frames can often be ameliorated on old tapes by repacking the tape before capture. Use a slow-rewind VCR and wind the tape to its end. Then rewind to the beginning. You might have to do this twice. The idea is to get the tape evenly rewound onto the feed size, for smoother transport on playback. You'd be surprised how often it helps.

The mvtools script I used is attached. There are many members here who are more expert with mvtools and chroma cleaners than I am. They'll have more and better ideas.

[jagabo]

I can't seem to find the MCtemporaldenoise filter for avisynth for download anywhere...

http://latoninf.free.fr/d9/MCTD/MCTemporalDenoise.v1.4.20.avsi
http://avisynth.org/mediawiki/MCTemporalDenoise
http://forum.doom9.org/showthread.php?t=139766