Color corrections in VirtualDub

[GovertdeKat]

Hi everybody,

I am in the process of capturing and enhancing some old HI8/VHS tapes in VirtualDub. Everything is going pretty well, but with one video I am encountering some color problems. Please see red colors below. Is there a simple filter to do something about this?

Many thanks


[Attachment 44266 - Click to enlarge]

[jagabo]

You should upload a video sample (not reencoded) instead of an image.

[johnmeyer]

Short answer: Colormill.

As for your image, it is WAY too saturated. Before you start correcting colors, take care of that. It looks like you used a capture card which has proc amp settings. If so, play around with the adjustments before you do any more captures and see if you can correct the problem there.

Actually, if you tell us what hardware you are using (name/model of VCR; capture card; post production software) the people here might be able to give even more advice.

[Bernix]

Hi,
it is oversaturated, and color correction is needed, but I think main question is because there is ghost or how to say (shifted red channel) to left. Sky sees also unnaturally.

Bernix

[johnmeyer]

Hi,
it is oversaturated, and color correction is needed, but I think main question is because there is ghost or how to say (shifted red channel) to left. Sky sees also unnaturally.

Bernix

With NTSC video, reds often "bloom," especially when you oversaturate. You lucky people in PAL-land don't have this problem. My guess is that if he figures out how to not capture with so much saturation, the redbloom/offset will take care of itself.

[jagabo]

I was thinking there might be a problem with blending of the chroma channels. Like when interlaced YV12 is treated as progressive YV12, a common problem with VirtualDub. That's why I asked for a video sample.

[LMotlow]

I am in the process of capturing and enhancing some old HI8/VHS tapes in VirtualDub. Everything is going pretty well

Doesn't look like it's going pretty well to me. You've given no info about what you're using for capture or how you're controlling input levels (which your image says you obviously aren't doing). What do you expect us to do with a sample you've already enhanced by deinterlacing and reprocessing? Are you actually capturing at 564x447 ? That's not an even-numbered frame dimension.

Ever heard of a histogram or a vectorscope? VirtualDub has a nice one that can tell you a lot if you learn how to use it.

You should upload a video sample (not reencoded) instead of an image.

Ditto.

[GovertdeKat]

Hereby a short clip. That might give some more information. My connection was:

Panasonic NV-HD830 VCR == COMPOSITE == Panasonic DMR-ES10 == S-VIDEO == MAGIX USB GRABBER == Samsung laptop.

One more thing. This VHS was made in New Zealand. The rest of the equipment is from europe. This color problem does not occur with my homemade video's. I didn't add any filters yet.

[LMotlow]

Thanks for the video sample

The script below helped the colors a bit, as most corrections need to be done in the original colorspace. Unfortunately your original colorspace appears to be RGB, so many darks and highlights are permanently destroyed and can't be recovered. But you have problems beyond color that the script didn't address, mainly because you need better capture gear instead of more filters.

ConvertToYV12(interlaced=false)
AssumeTFF()
QTGMC(preset="very fast",EZDenoise=1,DenoiseMC=true,ChromaNoise=true,Denoiser="dfttest",border=true)
FixChromaBleeding()
SmoothTweak(Saturation=0.9)
ChromaShift(C=6,V=2)
MergeChroma(awarpsharp2(depth=30).awarpSharp2(depth=15))
SmoothLevels(24,1.25,255,16,250,protect=6)
ConvertToYUY2(interlaced=false)
FixVHSOversharp(20,16,12)
FixVHSOversharpL(30,12,8)
FixVHSOversharpL(20,12,8)
Tweak(Sat=0.8,StartHue=85,EndHue=260,dither=true,coring=false)

SeparateFields().SelectEvery(4,0,3).Weave()
Crop(12,0,-12,-8).AddBorders(12,4,12,4)
ConvertToYV12(interlaced=true)

[GovertdeKat]

Many thanks. Is there also a way to change to original colorshape while capturing? Other capture hardware isn't an option sadly.

[jagabo]

Many thanks. Is there also a way to change to original colorshape while capturing?

Go through the options in the capture software and change the capture to YUY2, UYVY, or other YUV 4:2:2 color subsampling.

[GovertdeKat]

Great, I use VirtualDub, so that won't be hard to find I think.

[LMotlow]

Many thanks. Is there also a way to change to original colorshape while capturing?

Go through the options in the capture software and change the capture to YUY2, UYVY, or other YUV 4:2:2 color subsampling.

Good idea. And set compression in VirtualDub to huffyuv lossless, will reduce file size by 60% and even smaller than that compared to RGB. YUY2 is more like the the way color is stored on your tapes.

[lordsmurf]

Short answer: Colormill.
As for your image, it is WAY too saturated. Before you start correcting colors, take care of that. It looks like you used a capture card which has proc amp settings. If so, play around with the adjustments before you do any more captures and see if you can correct the problem there.
Actually, if you tell us what hardware you are using (name/model of VCR; capture card; post production software) the people here might be able to give even more advice.

^ Best answer.

[raffriff42]

Color Mill, had not heard of it before -- is this what you are talking about?
http://fdump.narod.ru/rgb.htm

You might want to also try VdubFM's built-in 6-axis color correction.

[johnmeyer]

Yes, that is where you get Color Mill.

[GovertdeKat]

Unfortunately your original colorspace appears to be RGB, so many darks and highlights are permanently destroyed and can't be recovered. [/CODE]

How can you see this? I have captured the video with Huffyuv and within my capture pin settings the colorspace/compression is set at YUY2. I have also checked this within the software of the capture card.

Am I missing something? I can't use the option VIDEO -> FORMAT, but that seems to be normal a lot of the times.

[LMotlow]

The free utility MediaInfoXP reads your sample as RGB. This was confirmed as RGB24 using the Avisynth Info() function. Look at the third line of overlaid text in the image below (white arrow, upper left):



If you saved your YUY2 video sample in VirtualDub using the "full processing mode", the sample was automatically converted to VirtualDub's default output colorspace, which is uncompressed RGB24 (not huffyuv). If you want to save an edit in the original input colorspace, use "direct stream copy" mode.

Avisynth function:

AVISource("whatever\sample.avi")
AssumeTFF()   #<-- or BFF, whichever applies. Avisynth's default is BFF.
Info()

[raffriff42]

One thing about losing highlights/lowlights: some capture tools (for example, Fraps) store YUV video as full range; if this video is converted to RGB as if it was the much more commonly seen limited range YUV, the contrast range is expanded and the extremes are clipped. One solution for this would be to apply the VirtualDub Alias format filter and specify component range = full.

How can you see this? I have captured the video with Huffyuv ...

There's been a mistake somewhere. The sample you linked to is uncompressed RGB. FFmpeg says:

Input #0, avi, from 'E:\Data\Downloads\Sample.avi':
  Duration: 00:00:05.40, start: 0.000000, bitrate: 250392 kb/s
    Stream #0:0: Video: rawvideo, bgr24, 720x576, 250688 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 2 channels, s16, 1536 kb/s

[LMotlow]

Who said anything about Fraps? It's vanilla VHS captured with Virtualdub using huffyuv/YUY2, and making no attempt to control the original input levels during capture. Seen this hundreds of times. Then it was saved in VirtualDub using "full processing mode" and got out as default uncompressed RGB24. The original playback has too much contrast at both ends, and got clipped in the darks and brights twice: once during capture, then in RGB. And the original camera shot probably had blown out highlights to begin with -- you can thank the camera's AGC for some of that, looks like its AGC had a conniption fit with that strong backlighting.

[lordsmurf]

To add:

The original video has color bleeding.
Just do a chroma offset in Avisynth.

And then some color work in an NLE or VirtualDub Colormill.

The bigger issue is that the original capture is not very good.

Something like this is far more realistic to the scene: