VHS videos appear to be damaged - can only deinterlace with blend

[Alwyn]

What "blend" are you talking about? Which filter(s) did you use?

I suspect the Blend option in the Virtual Dub Deinterlace filter. There is no Weave option.

[Ferrari420]

Yes that's right, the built in VirtualDub deinterlace filter.

How can I smart blend/selective blend/motion adaptive blend my videos with VirtualDub? That will produce a better result than just blend.

[Sharc]

Yes that's right, the built in VirtualDub deinterlace filter.

OK, thanks.
'Base-rate blending deinterlacing' builds the frames by blending (averaging, mushing) weighted fields. On the positive this reduces flicker (brightness and color fluctuations) and introduces a kind of motion blur which mitigates the 'stroboscopic' effect of the deinterlaced 25p video. On the downside one pays with reduced sharpness and reduced resolution (blurred picture).
A tutorial about deinterlacing principles can be found here (scroll down to How to deinterlace video, methods of deinterlacing). It's an old site, but much of it is still valid:
https://www.100fps.com/index.htm#howto
Quote from there: In other words: Deinterlacing by blending (which is one of the most frequent ways to deinterlace) simluates fluent motion by blurring and "mushes" 2 consecutive pictures together. Thus in fact you reduce the quality down to a quarter of the possible quality.

But if you are happy with the result which you obtained it's all which eventually counts.

How can I smart blend/selective blend/motion adaptive blend my videos with VirtualDub? That will produce a better result than just blend.

Avisynth is your friend.
A "GUI" which supports the usage of Avisynth (and Vapoursynth) and its filters is Selur's Hybrid. But be warned: It's not for video rookies. Some basic knowledge of Avisynth is very helpful (mandatory almost) for using Hybrid. At least Hybrid takes the pain from you having to install Avisynth filters and all its dependencies yourself.
Maybe someone can advise how to achieve similar quality with VirtualDub filters.

But again, those color issues in your sources have nothing to do with the deinterlacing. Blend-deinterlacing just mushes everything to an average.

[lordsmurf]

[A "GUI" which supports the usage of Avisynth (and Vapoursynth) and its filters is Selur's Hybrid. But be warned: It's not for video rookies. Some basic knowledge of Avisynth is very helpful (mandatory almost) for using Hybrid. At least Hybrid takes the pain from you having to install Avisynth filters and all its dependencies yourself.

Nah, easy enough to learn.

Maybe someone can advise how to achieve similar quality with VirtualDub filters.

None exist. I wish.

Buy that man a beer!!!

[Sharc]

Sharc's favourite! Cheers!

[Ferrari420]

[QUOTE=Sharc;2718661]

The goal is to make the samples deinterlaced.

Goal? Not recommended to deinterlace your interlaced video. For DVD leave it interlaced, 25i, means 25 interlaced frames per second= 50 fields per second, perfectly DVD compliant. But we have been through this in your former thread. For some obscure reasons like "plays back too fast" you stick to deinterlacing to 25p it seems. So be it.

I have attached a sample video which is interlaced and in the second video I deinterlace it with double frame rate, top field first with Yadif selected in the deinterlace filter in VirtualDub. Play them side by side and see which looks faster. In my opinion the original is slightly slower while the deinterlaced 50P is slightly faster. The original looks choppier while the deinterlaced file looks smoother in motion.

[Sharc]

Play them side by side and see which looks faster.

Here playing them side by side. Exactly same speed, synchronous frame by frame. The duration of the video is exactly the same for the interlaced and the double-rate deinterlaced version: 45s680ms. You can check with MediaInfo. The player (TV) will deinterlace the interlaced version on the fly during playback (left picture).

(Sidenote: I think you are aware that your files are in no way DVD compliant ....)

[lollo]

Play them side by side and see which looks faster. In my opinion the original is slightly slower while the deinterlaced 50P is slightly faster. The original looks choppier while the deinterlaced file looks smoother in motion.

You need an analytical methodology to determine the characteristics of the videos, not just a quick overview of what is displayed in your player.
AviSynth / VirtualDub can help, and I am sure our friend Sharc is willing to share his secrets with you

[Sharc]

Play them side by side and see which looks faster. In my opinion the original is slightly slower while the deinterlaced 50P is slightly faster. The original looks choppier while the deinterlaced file looks smoother in motion.

You need an analytical methodology to determine the characteristics of the videos, not just a quick overview of what is displayed in your player.
AviSynth / VirtualDub can help, and I am sure our friend Sharc is willing to share his secrets with you

I will relegate this to Alwyn and enjoy my beer now. He may perhaps want to demonstrate/explain it using Vdub
In the meantime Ferrari420 may want to study the fps100 link of post#33. There are certainly more tutorials floating around about the subject of interlacing and deinterlacing, and how to play it correctly back, etc.

[lollo]

Enjoy your beer then, you did more than enough!

[Sharc]

@Ferrari 420: The beer has gone, so here some explanations.

You have 2 versions of your clip (post#36):
a) interlaced, 25 interlaced frames per second. Each frame has 2 fields (even and odd) which are pairwise woven (interlaced) into a frame.
The fields have been taken at a pace of 50 per second by the camera (PAL), so the temporal spacing between fields is 1/50=20ms, i.e.one field every 20ms. As 2 fields are woven (interlaced) into one frame the framerate becomes half of the field rate, means 25fps, means one interlaced frame every 40ms.
b) your double-rate deinterlaced version. The deinterlacing process (your yadif double-rate) created one frame from each field of a), so you have now the double number of frames compared to a) which need to played at 50fps in order to keep the playback duration at 45s680ms.

a) and b) have exactly the same duration of 45s680ms. You can check it using MediaInfo for example.

There are different ways to play these files:
Play a) without deinterlacing at 25fps. On your progressive PC monitor you will see the interlaced frames as combed pictures (mice teeth, jaggies) which are played at 25fps. Playback duration is 45s680ms. The combed pictures look ugly, so the video a) should be deinterlaced for pleasant viewing. The deinterlacing has to be done by the player (TV for example) - provided that the video is correctly flagged as interlaced - and can be done in 2 ways: base rate or double rate.
- Base rate deinterlacing creates frames from the 2 fields using methods as explained in the 100fps.com link, with their pros and cons. Base-rate deinterlaced video should be played back at 25fps which gives a playback duration of 45s680ms for your clip.
- For double rate deinterlacing (preferred) the player creates (interpolates, synthesizes) one frame out of every field, so you get frames at a speed of 50fps, played in 45s680ms for your clip, means 1 frame every 20ms.

For file b) the deinterlacing has been done by yourself using yadif double rate. So no deinterlacing needs to be done by the player. The player will play it at 50fps. That's fine, but unfortunately the DVD specs does not allow 50fps, only 25fps (PAL), so you can't put your smooth double-rate variant b) onto a compliant DVD disc.

Anyway, for demonstrating that your variants a) and b) are the same with respect to temporal resolution and playback time (45s680ms), I applied double-rate deinterlacing to a) and put is side-by-side in post#37. However, as 50fps is not DVD compliant you would have to author your DVD as interlaced (case a) and let the player do the deinterlacing if you want to preserve the original temporal resolution (temporal motion "smoothness") of your captures.

I hope this has contributed to clarify your "playback speed" concern.

Edit:
And for the sake of completeness below the side-by-side comparison of baserate deinterlacing vs doublerate deinterlacing (as modern TVs will normally play interlaced DVDs). You can see that the right picture moves smoother, the left picture looks more "stroboscopic" or "choppy". The duration is the same for both (45s680ms), but the video on the right has twice as many different motion pictures (means one for each field of the interlaced source), therefore the motion is smoother.