First: I have supreme respect for the art of restoration, and I have some sense of the enormous task it is. I'm equally in awe of those of you who have mastered the art. In another life I may have joined you, but for now, I need to settle for something less than perfection.
Here's my setup:
- Basic dual-core Athlon w/ XP
- Bt878 capture card
- Consumer-grade Sony VCR w/ S-Video out
Trying to get a fairly good VHS->DVD conversion. Just a few questions.
I don't have a ton of time and money to sink into this. As much as I would *love* to meticulously restore every frame the way I've seen some of you wizards do, I just can't invest that right now. Some key phrases that describe my end goal: "watchable, free from strong visual distractions, decent quality." I'm not going for award-winning restoration at this point, just "pretty good." I know that's subjective, but bear with me.
I've used VirtualVCR to capture one tape with "pretty good" results, saved to lossless AVI. The picture is surprisingly detailed and sharp for my amateur gear, the audio is near perfect, and all of it is definitely "watchable." Half of me is just like, "convert to MPEG2 and be done with it." The other half wants to try and address a few nits, as long as it doesn't take forever:
- Moderate chroma shift
- Light temporal noise
- HSV issues (certain scenes are oversaturated, others are undersaturated with incorrect hue, others are very dark, others very light, etc.)
I've played with VirtualDub's flaXen VHS plugin to address chroma shift, and the built-in temporal smoother, which actually worked really well! I haven't figured out any way to deal with the HSV issues. I assume I'll need to correct them scene-by-scene. If that's the case, forget it (at least for now). If there's an easy adaptive/automatic correction, or somehow to do scene-based correction without hours of prep, I'm definitely interested.
So overall I'm looking for any general tips for doing VHS->DVD conversion reasonably well, with very modest hardware, time and budget. I've reviewed most how-tos on videohelp and digitalfaq, so I'm familiar with the basics. My thought is to get the best basic capture I can now, while holding on to the tapes in case I get more time/money later. There's still a huge win in a decent, watchable digitization IMHO.
Thanks in advance!
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For starters there is not much to restore to begin with. SD video is (in square pixels) about 640x480.
That is already not much but it is far worse for VHS, it has a resolution of about 333×480 pixels, while the color resolution is a dismal 40×480. And this under ideal conditions. We are talking about resolutions of 0.16 Megapixel (no, not a typo) and far less resolution in the color.
Don't expect too much from restoration, it is completely incomparable with film restoration. It is very limited and often people who try to restore butcher more than they actually repair, unless of course you happen to love oversharpened cartoonified videos.
Here are some must do's:
- Use a decent, preferable PCI based, capture card, not some $9,99 USB Walmart card!
- Capture lossless, disk space is dirt cheap there are no excuses for not doing it!
- Make sure the signal remains interlaced!
- Archive your captures and store them at at least two physically separated locations.
- Generally stay away from sharpening, sharpening destroys resolution! Unless you like cartoons it does not make any sense!
- Be very easy on noise reduction. There are some good programs but the problem is the worse the source the harder it is to distinguish noise from content!
- Finally there are no miracle filters, don't get carried away!
What you can do:
- Replace some bad frames (with other frames)
- Fixup colors
- Fixup luma levels
- Upconvert! No, just upconverting does not make anything better or make it HD but if you use filters you have more pixels to work with and that can be an advantage, if you know what you are doing!
Last edited by newpball; 25th Feb 2015 at 16:18.
You describe mostly what I've already done:
- Keep interlaced
- Capture to lossless YUY2/PCM
- PCI-based Bt878 capture card
- No sharpening even necessary, it's already surprisingly sharp!
- Light noise reduction to improve compressibility
You talk about fixing up luma and chroma, any specific tips on how to do that? Other than chroma shift, which I already know how to correct, any tips on improvement there?
Looks like you are doing the right things!
Generally start with correcting the white level. See if you can find something that you know is white, don't guess, eyes are deceiving. Also make sure it is not a specular highlight or a burnout white as there is no color information in there. Then adjust the black and white levels. Don't maximize, it's not some one off Photoshop picture, a video is a continuous set of pictures and obviously some will be brighter than other. Keep it within reason and apply common sense.
You can't really restore colors as there is not enough information to begin with but applying some Lumetri usually makes things a bit more palatable.
There is actually quite a lot of denoising you can do with VHS video. First, as already pointed out, there isn't much resolution, so there is far less detail you can destroy. Second, many of the same reasons that contribute to the resolution being so much less than 720x480 (656x480 in square pixel measurement) also contribute to the video being full of noise.
I've published a VHS noise reduction script here and at doom9.org many times (I just posted it again today at doom9.org). Here is a before/after that shows what you can expect. Make sure to change the YouTube setting to 720p or, if your computer and connection can maintain smooth playback, use 1080. That will seem like overkill for VHS, but because the video contains two side-by-side VHS videos, you actually do have to go to at least 720p to see the full effect. Also, click on the full-screen button so you can fill up your entire screen. If you don't, you won't be able to see as much of the noise reduction.
The short second scene is where you'll most easily notice the difference because the camera isn't moving much.
Last edited by johnmeyer; 25th Feb 2015 at 17:10. Reason: change "you" to "your"
I've never seen any autolevels plugin that works. This includes not only those available for AVISynth, but also some pretty sophisticated (and expensive) plugins available with commercial packages. These auto plugins can be useful for matching shots, but they usually fall down pretty badly when you ask them to do things like correct for video taken with the balance set to indoor when taking video outdoors, or adjusting video that was taken when the camera's "auto white balance" function failed to calibrate correctly.
Also, gamma (levels) is a very subtle thing, and you ideally want complete control over every point on the histogram (the mapping of luma for each pixel in the input, to each corresponding pixel in the output video). In my experience, most autolevels algorithms tend to "punch up" the video too much, resulting in very contrasty video.
However, if you have a plugin you think might work, try it out and see what you think. YMMV.
Speaking for myself, I do all color and levels corrections within my video editing program (Vegas). It takes some time and effort, but the results are much better than what you get with automatic adjustments.