Selur's Little Message Board

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I have a digitized VHS (no access to the original tape) file where it looks like the field heads wobble slightly (vertically) independent of each other. So even after deinterlacing with QTGMC there is some combing or echo (I'm not sure of the right way to describe this) that can last several seconds before aligning again and looking correct. Is there any hope to fix/restore this?

[attachment=3265]

If you can share a small sample of the original, I can have a look at it tomorrow evening.
My first try would be to look at the separated fields, an think about whether filtering the separated fields before deinterlacing might help. Also, maybe using fields matching instead of deinterlacing is the better approach,..

Maybe the separated fields are already messed Up,...

Cu Selur

Thanks! I tried VITVC as well since this is a DVD digitization of a telecined movie, and it gives overall slightly more appealing results, but it still has a lot of the same artifacts you seen in the screenshot.

Here is a 30-second clip of the VHS warning.

And here is a 2-minute clip of the movie opening credits which shows the same effects.

Looking at the 30sec sample:
Try Filtering->Vapoursynth->Frames->Stabilize->ReduceFlicker, it will at least stabilize the video.
Text will still be messed up, since the fields are already broken.

Looking at the 2min sample, I would also Crop and add Filtering->Vapoursynth->Frames->Stabilize->Stab and probably Filtering->Vapoursynth->Artifacts->SpotLess.

Cu Selur

Thanks, I'll give this a try and report back. Also, just to make it interesting, I believe the movie (not the VHS warning, of course) was a PAL telecine (not sped up) on VHS, then converted to NTSC DVD.

Haven't really looked at frame pattern Smile

( no horizontal movement, so hard to spot )
But reading https://forum.doom9.org/showthread.php?t=176104 might be interesting.
Norm conversions are always a pain, you can try using sRestore to get to 25 fps or TIVTC in mode 7 and aim for 25fps,..

Cu Selur

Still sticking with my guess that the text lines look so horrible because the two VHS heads where vertically wobbling slightly out of sync from each other, I tried separating the top/bottom fields into a single stream with one field per frame, stabilize that, then reweave back to proper interlaced.

Interestingly, when I used ffmpeg to separate fields, then hybrid stab(mirror=15, dxmax=0, dymax=2, range=1) on that new half-height field-per-frame file, then finally ffmpeg again to weave back to interlaced, I was happy with the result and it did look improved to my eye.

I thought I should be able to accomplish the same thing with a custom VS filter, so tried this script (below) inserted just before the End event, but the results did not turn out the same at all. Any thoughts why this may be?

Code:
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/MiscFilter/MiscFilters/MiscFilters.dll")

core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/DenoiseFilter/ZSmooth/zsmooth.dll")

core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/Support/libmvtools.dll")

core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/Support/DePan.dll")

import stabilize

clip = core.std.SeparateFields(clip, tff=True)

clip = core.std.AssumeFPS(clip=clip, fpsnum=60000, fpsden=1001)

clip = stabilize.Stab(clp=clip, mirror=15, dxmax=0, dymax=2, range=1)

clip = core.std.DoubleWeave(clip, tff=True)

clip = core.std.SelectEvery(clip, 2, 0)

clip = core.std.AssumeFPS(clip=clip, fpsnum=30000, fpsden=1001)

The difference is quite obvious when you apply to the clip of the VHS warning that I linked previously.

These are the ffmpeg commands I used to separate fields and weave:

Code:
ffmpeg -i <in> -vf separatefields -c:v ffv1 -r "60000/1001" -c:a copy -map_metadata -1 <out> 

ffmpeg -i <in> -vf weave -c:v ffv1 -r "30000/1001" -c:a copy -map_metadata -1 <out>

Quote:Any thoughts why this may be?

No, no clue what the characteristics of the ffv1 file the first call outputs are.
=> not sure that this will actually do the same. Smile

For stabilization, try Stab+SpotLess+ReduceFlicker+TemporalFix. (https://www.mediafire.com/file/fygwu6cl4...e.mkv/file)

Code:
# Imports

import vapoursynth as vs

# getting Vapoursynth core

import ctypes

import sys

import os

core = vs.core

# Limit frame cache to 48473MB

core.max_cache_size = 48473

# Import scripts folder

scriptPath = 'F:/Hybrid/64bit/vsscripts'

sys.path.insert(0, os.path.abspath(scriptPath))

# Loading Support Files

Dllref = ctypes.windll.LoadLibrary("F:/Hybrid/64bit/vsfilters/Support/libfftw3f-3.dll")

# loading plugins

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/libmotionmask.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/ColorFilter/Retinex/Retinex.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/vszip.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/DenoiseFilter/CTMF/CTMF.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/TCanny.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/libfillborders.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/libtemporalmedian.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/FrameFilter/ReduceFlicker/ReduceFlicker.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/MiscFilter/MiscFilters/MiscFilters.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/DePan.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/DenoiseFilter/ZSmooth/zsmooth.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/GrainFilter/AddGrain/AddGrain.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/DenoiseFilter/NEO_FFT3DFilter/neo-fft3d.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/DenoiseFilter/DFTTest/DFTTest.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/EEDI3m_opencl.dll")# vsQTGMC

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/ResizeFilter/nnedi3/NNEDI3CL.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/libmvtools.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/fmtconv.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/DeinterlaceFilter/Bwdif/Bwdif.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/akarin.dll")

core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/SourceFilter/DGDecNV/DGDecodeNV_AVX2.dll")

# Import scripts

import vs_temporalfix

import SpotLess

import stabilize

import qtgmc

import validate

# Source: 'C:\Users\Selur\Desktop\A1_t00-00.00.10.247-00.00.39.835.mkv'

# Current color space: YUV420P8, bit depth: 8, resolution: 704x480, frame rate: 29.97fps, scanorder: top field first, yuv luminance scale: limited, matrix: 470bg, transfer: bt.601, primaries: bt.601 ntsc, format: mpeg-2

# Loading C:\Users\Selur\Desktop\A1_t00-00.00.10.247-00.00.39.835.mkv using DGSource

clip = core.dgdecodenv.DGSource("J:/tmp/mkv_1e10dacb566c29e0d6d6d62f9640a558_853323747.dgi",fieldop=0)# 29.97 fps, scanorder: top field first

frame = clip.get_frame(0)

# setting color matrix to 470bg.

clip = core.std.SetFrameProps(clip, _Matrix=vs.MATRIX_BT470_BG)

# setting color transfer (vs.TRANSFER_BT601), if it is not set.

if validate.transferIsInvalid(clip):

  clip = core.std.SetFrameProps(clip=clip, _Transfer=vs.TRANSFER_BT601)

# setting color primaries info (to vs.PRIMARIES_BT470_BG), if it is not set.

if validate.primariesIsInvalid(clip):

  clip = core.std.SetFrameProps(clip=clip, _Primaries=vs.PRIMARIES_BT470_BG)

# setting color range to TV (limited) range.

clip = core.std.SetFrameProps(clip=clip, _ColorRange=vs.RANGE_LIMITED)

# making sure frame rate is set to 29.97fps

clip = core.std.AssumeFPS(clip=clip, fpsnum=30000, fpsden=1001)

# making sure the detected scan type is set (detected: top field first)

clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_TOP) # tff

# Deinterlacing using QTGMC

clip = qtgmc.QTGMC(Input=clip, Preset="Fast", InputType=0, TFF=True, TR2=1, SourceMatch=0, Lossless=0, opencl=True) # new fps: 59.94

# Making sure content is preceived as frame based

clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive

# stabilizing using Stab

clip = stabilize.Stab(clp=clip,mirror=15,dxmax=0,dymax=2)

# removing flickering using ReduceFlicker

clip = core.rdfl.ReduceFlicker(clip=clip, strength=3, aggressive=1)

# Spot removal using SpotLess

clip = SpotLess.SpotLess(clip=clip, radT=3, rec=True, pel=1, smoother="zsmooth")

# changing range from limited to full range for vsTemporalfix

clip = core.resize.Bicubic(clip, format=vs.YUV420P8, range_in_s="limited", range_s="full")

# setting color range to PC (full) range.

clip = core.std.SetFrameProps(clip=clip, _ColorRange=vs.RANGE_FULL)

# stabilizing using Temporalfix

clip = vs_temporalfix.vs_temporalfix(clip=clip,denoise=True)

# changing range from full to limited range for vsTemporalfix

clip = core.resize.Bicubic(clip, format=vs.YUV420P8,range_in_s="full", range_s="limited")

# setting color range to TV (limited) range.

clip = core.std.SetFrameProps(clip=clip, _ColorRange=vs.RANGE_LIMITED)

# adjusting output color from: YUV420P8 to YUV420P10 for NVEncModel

clip = core.resize.Bicubic(clip=clip, format=vs.YUV420P10)

# set output frame rate to 59.94fps (progressive)

clip = core.std.AssumeFPS(clip=clip, fpsnum=60000, fpsden=1001)

# output

clip.set_output()

but the text is still ugly.

Cu Selur

(21.09.2025, 18:58)Selur Wrote: [ -> ]
Quote:Any thoughts why this may be?
No, no clue what the characteristics of the ffv1 file the first call outputs are.

Here's the process on a smaller clip, I prefer the output here after the fields are stabilized and woven back to interlaced. I'm surprised I can't duplicate this using a pure VS script (mostly suspicious of my lack of
understanding here, not VS).

https://ln5.sync.com/dl/1cce6c470#5ck9r5...j-kgnb327u

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