How to fix poor Interlaced to Progressive Conversion with Avisynth?

[VideoFanatic]

I have a VHS-to-DVD video which for some reason somebody converted from 720 x 480i (29.97 fps) to progressive at some stage which lost half the temporal resolution. It's 5.7 Mbps but looks like crap. Is the quality lost or could I get any back by converting back to interlaced? I don't have the original video, this is all I have. Here's a clip.

Do I need any special filters or do I just do this to re-interlace it? I need to keep it 29.97 fps as Bluray doesn't support progressive 720 x 480 60 fps.

AssumeTFF() 
SeparateFields()
SelectEvery(4,0,3)
Weave()

[poisondeathray]

Besides all the other VHS problems (noise, damage etc...) You can try doubling the frames 29.97p => 59.94p (generating new inbetween frames) with motion interpolation (mvtools2, eg. interframe, svpflow, mflowfps) , the problems are edge morphing artifacts that can occur

You only need to re-interlace if you were going back to DVD (and you can't re-interlace it from a 29.97p source - it needs 59.94p)

[VideoFanatic]

Is there any point in me going to 59.94 fps though as the video is going onto a Bluray and Bluray doesn't supports 720 x 480 at 59.94 fps so I need to keep it interlaced at 29.97 fps.

[poisondeathray]

Yes, for SD blu-ray you would re-interlace it then

The question is how do you get 59.94 motion samples per sec before you re-interlace ?

The options are
1) duplicate frames - changefps(60000,1001)
2) blended frames - convertfps(60000,1001)
3) motion interpolation - one of the options listed above

They all have pros/cons. Option 3 produces the smoothest results, but at expense of edge morphing artifacts


You need to start with a 59.94p source before you reinterlace

#59.94p source
AssumeTFF()  
SeparateFields() 
SelectEvery(4,0,3) 
Weave()

[jagabo]

Just encode the video interlaced. The encoder and the decoder don't care if the frames are progressive. Of course, it won't be as smooth as true 30i video. And the script you proposed in the first post would give you 15 fps, not 30 fps.

[poisondeathray]

yes, if you just encode the 29.97p video as interlaced it would work. Visually it would give similar results to option (1) above

[VideoFanatic]

OK thanks. I will just encode as interlaced then like I usually do. Is there anything special which I should do to the video or will this script do to clean it up? Also should I have DegrainMedian on interlaced=true or not?

Mpeg2Source("L:\2 = New\z = Encode\Raw December 23 2002 Fixed.d2v", CPU=6)

RemoveSpots()

DeGrainMedian(limitY=2, limitUV=3, mode=1, interlaced=true)

Tweak(Bright=-0, Sat=0.8, Cont=1.0, Hue=20.0, Coring=False)

Crop(0,0,-0,-16)
AddBorders(0,8,0,8, $000000)

[sanlyn]

It will take a lot more than that script to "clean up" that video. But you may as well use it. IMHO there's not much you can do with it.