[BUG] Incorrect range signalling

[r3dfx]

Sorry, I wouldn't call myself an advanced user( I can't find SetMemoryMax setting. It says " Sometimes reducing this value can allow you to increase X for a speedup" on avisynth wiki...
I see only Limit Cache option in Script settings
This is a typical .vpy script of my job:

# Imports
import vapoursynth as vs
# getting Vapoursynth core
import ctypes
import sys
import os
core = vs.core
# Import scripts folder
scriptPath = 'C:/Program Files/Hybrid/64bit/vsscripts'
sys.path.insert(0, os.path.abspath(scriptPath))
# Loading Support Files
Dllref = ctypes.windll.LoadLibrary("C:/Program Files/Hybrid/64bit/vsfilters/Support/libfftw3f-3.dll")
# loading plugins
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/GrainFilter/RemoveGrain/RemoveGrainVS.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/GrainFilter/AddGrain/AddGrain.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/DenoiseFilter/NEO_FFT3DFilter/neo-fft3d.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/DenoiseFilter/DFTTest/DFTTest.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/Support/EEDI3m.dll")# vsQTGMC
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/ResizeFilter/nnedi3/vsznedi3.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/fmtconv.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/MiscFilter/MiscFilters/MiscFilters.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/DeinterlaceFilter/Bwdif/Bwdif.dll")
core.std.LoadPlugin(path="C:/Program Files/Hybrid/64bit/vsfilters/SourceFilter/LSmashSource/LSMASHSource.dll")
# Import scripts
import qtgmc
import validate
# Source: 'I:\RAW\VITALII\tape4_2.mkv'
# Current color space: YUV420P8, bit depth: 8, resolution: 720x576, frame rate: 25fps, scanorder: top field first, yuv luminance scale: full, matrix: 709, transfer: bt.709, primaries: bt.709, format: AVC
# Loading I:\RAW\VITALII\tape4_2.mkv using LWLibavSource
clip = core.lsmas.LWLibavSource(source="I:/RAW/VITALII/tape4_2.mkv", format="YUV420P8", stream_index=0, cache=0, prefer_hw=0)
frame = clip.get_frame(0)
# setting color matrix to 709.
clip = core.std.SetFrameProps(clip, _Matrix=vs.MATRIX_BT709)
# setting color transfer (vs.TRANSFER_BT709), if it is not set.
if validate.transferIsInvalid(clip):
  clip = core.std.SetFrameProps(clip=clip, _Transfer=vs.TRANSFER_BT709)
# 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 PC (full) range.
clip = core.std.SetFrameProps(clip=clip, _ColorRange=vs.RANGE_FULL)
# making sure frame rate is set to 25fps
clip = core.std.AssumeFPS(clip=clip, fpsnum=25, fpsden=1)
# 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", TFF=True) # new fps: 50
# Making sure content is preceived as frame based
clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive
# adjusting output color from: YUV420P8 to YUV422P8 for FFV1Model
clip = core.resize.Bicubic(clip=clip, format=vs.YUV422P8, range_s="full")
# set output frame rate to 50fps (progressive)
clip = core.std.AssumeFPS(clip=clip, fpsnum=50, fpsden=1)
# output
clip.set_output()

[Selur]

You are using Vapoursynth not Avisynth.
And yes, the "Limit Cache"-option is basically the same. (but rarely needed)
You might want to try limiting the thread count.
Since your video is AVC, and LWLibavSource using hardware decoding ('Libav hardware decoding mode') might also help (or hurt the performance and handling of the source. (You could also try whether using DGDecNV or FFmpegSource2 does change things for you.)
En-/Disabling OpenCL and/or DFTTest2 might also change things.

Cu Selur

[r3dfx]

Yes, I know that I use vapoursynth. I thought QTGMC library is identical for them
Thank you for the tips, will try! Unfortunately I have to wait like 30 or 40 minutes to notice a difference
UPD: I can't enable DFTTest2 (always greyed out)
UPD2: I tried enabling DGDecNV + OpenCL and it seems to partly fix the problem (I really hope). Unfortunately my software RAID0 on chinese SSDs (cringe, I know) isn't working well for this. Now, on 50%+ it starts oscillating between encoding and writing to disk...