What to do with interlaced VHS captures for presentation?

[armyofquad]

I've seen it suggested that interlaced VHS captures should stay interlaced for TV, de-interlaced for streaming.

I've seen people stick to these 2 concepts being separate things.

In this day and age, the line is extremely blurred, and as an end user I can tell you this 2 tiered definition of viewing is woefully inadequate!

I view many things on a TV, so the defined TV viewing may be describing something more specific than what people are using the term for here.

Point is, we need 2 clearly defined circumstances, and processes:

How does one determine if a capture should remain interlaced or be de-interlaced?

If a VHS capture needs to be de-interlaced, how does one accomplish this?

Please keep this thread to actual interlaced material, such as home movies on VHS from a camcorder - no discussion of ivtc here please!

[Alwyn]

Just deinterlace it and be done with it. The only application I can see for interlaced is DVDs; there's little point in deinterlacing, then making the DVD authoring software re-interlace it.

If a VHS capture needs to be de-interlaced, how does one accomplish this?

-Your video editing software
-VDub, as I explained on the other topic
-Best: AVISynth using QTGMC. I haven't done a guide for that yet.

[_Al_]

I have all avis (well DVavis mostly, only some analog avis) QTGMC deinterlaced, but always in a directory where original, master interlaced avi is as well. Just stored master if in future there is more capable ai's to deinterlace it better. Always keeping both of them together, so they would not get lost.

As soon as you start to mix those avis with progressive videos, of course it is better to use those 60p deinterlaced versions in NLE. Like possible your case. Here you can see where that "general" Vegas project fps advice came from. To get good interlace converted into progressive you have to deinterlace to 60p, not 30p.

[armyofquad]

How?

Please do not litter this thread with more technobabble or incomplete thoughts. I want to know EXACTLY HOW, BEGINNING TO END, STEP BY STEP!!!!

Anything less does anyone and everyone that might read this thread a disservice and wastes their time.

For the love of god, if I hear someone say QTGMC one more time without actually explaining it.......

[Cornucopia]

Qtgmc

[lordsmurf]

http://avisynth.nl/index.php/QTGMC

Or use Hybrid
Open it, choose source and output encode settings on tabs,
Filtering tab has deinterlace,

(On tablet now, reason why brief, no images.)

[bar72]

I'll encode the file with RipBot. I capture at 25fps so it's just a case of load it up, click on avisynth radio button and select deinterlace, TFF 25fps. It's QTGMC Medium setting, which is not too slow and top quality. You can also do a little bit of mdegrain and get a smaller x264 encode.

[_Al_]

RipBot was first GUI, if Im not mistaken, that allowed simply edit Avisynth script. So in our case, like presented above, adding some lines for qtgmc deinterlace. Very handy and powerful.

[Archiveuse_3000]

If you want a step by step, A to Z beginner tutorial on how to use QTGMC, I highly recommend this one https://www.youtube.com/watch?v=C4PyyQoz6eo

I followed it to a T and it worked really well.

[oln]

I'll encode the file with RipBot. I capture at 25fps so it's just a case of load it up, click on avisynth radio button and select deinterlace, TFF 25fps. It's QTGMC Medium setting, which is not too slow and top quality. You can also do a little bit of mdegrain and get a smaller x264 encode.

If you follow this please use 50 fps (or 59.97 for NTSC) setting which it hopefully has if you want to do it properly and not throw away half the frames.

[bar72]

apologies for the error. I throw away half the frames as my TV doesn't play with 50fps and it's VHS. If OP wants 50fps then just select the deinterlacing preset for TFF > 50fps, if in PAL land.

[jagabo]

I throw away half the frames as my TV doesn't play with 50fps and it's VHS.

A TV not playing 50p video files is a legitimate reason for using 25p (keep you interlaced source for the future). But VHS isn't. VHS is interlaced like all other analog SD TV. It has 50 fields per second, where each field can come from a different point in time. 50p will be noticeably smoother as less flickery than 25p from such a source.

[jagabo]

If a VHS capture needs to be de-interlaced, how does one accomplish this?

Try this: https://forum.videohelp.com/threads/405720-FFmpeg-QTGMC-Easy%21

[bar72]

@jagabo, thanks for the info. I'm not an expert. I'll start transferring at 50fps then deinterlace to 25fps once I work out how to do it in avisynth as it isn't apparent in Ripbot how to do 50 to 25fps during conversion.

[jagabo]

@jagabo, thanks for the info. I'm not an expert. I'll start transferring at 50fps

You capture as 25 interlaced frames per second. Each frame contains two half pictures, called fields. Each field is supposed to be viewed separately and sequentially. So when properly displayed on an interlaced display you see 50 different fields per second. Since modern displays are progressive the frames need to be deinterlaced before displaying them. If you create full frames from each field (the default in QTGMC) you get 50 fps progressive with full motion (very smooth motion on a 50p display). If you convert to 25 fps you are missing half the motion and the video will flicker a bit during bright, high motion shots.

then deinterlace to 25fps once I work out how to do it in avisynth as it isn't apparent in Ripbot how to do 50 to 25fps during conversion.

With QTGMC you use the FpsDivisor setting

QTGMC(FpsDivisor=2)

Or you can explicitly discard every other frame yourself:

QTGMC()
SelectEven() # or SelectOdd()

[bar72]

Many thanks for the explanation jagabo. Also appreciate the QTGMC script. Thankfully I've only done a few caps and still have the source cassettes so I can redo them.

[bar72]

If a VHS capture needs to be de-interlaced, how does one accomplish this?

Try this: https://forum.videohelp.com/threads/405720-FFmpeg-QTGMC-Easy%21

Also, thanks for this, while I prefer to learn avisynth scripting, this looks like I can run if from a thumb drive when out and about which is handy )