[HELP] Export fails w/ Vapoursynth de-interlacing

[Canayhands]

I'm on ArchLinux using version 2025.05.17
Whenever I try to export a video it crashes during encoding no matter what as long as I use Vapoursynth de-interlacing.
When I switch to no Xsynth, everything works just fine. 



  HybridDebugOutput.txt.zip (Size: 15,83 KB / Downloads: 4)

[Selur]

1. Check the Vapoursynth Preview, it should show an error message.
2. Looking at the used script:

# Imports
import vapoursynth as vs
# getting Vapoursynth core
import sys
import os
core = vs.core
# Import scripts folder
scriptPath = '/usr/lib/python3.10/site-packages/'
sys.path.insert(0, os.path.abspath(scriptPath))
# Import scripts
import qtgmc
import validate
# Source: '/home/jonah/Desktop/VIDEO/HVR/00_0001_0000-00-00_000000.DV'
# Current color space: YUV411P8, bit depth: 8, resolution: 720x480, frame rate: 29.97fps, scanorder: bottom field first, yuv luminance scale: limited, matrix: 470bg, format: DV
# Loading /home/jonah/Desktop/VIDEO/HVR/00_0001_0000-00-00_000000.DV using LWLibavSource
clip = core.lsmas.LWLibavSource(source="/home/jonah/Desktop/VIDEO/HVR/00_0001_0000-00-00_000000.DV", format="YUV411P8", stream_index=0, cache=0, fpsnum=30000, fpsden=1001, prefer_hw=0)
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: bottom field first)
clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_BOTTOM) # bff
# adjusting color space from YUV411P8 to YUV444P16 for vsQTGMC
clip = core.resize.Bicubic(clip=clip, format=vs.YUV444P16, range_s="limited")
# Deinterlacing using QTGMC
clip = qtgmc.QTGMC(Input=clip, Preset="Slow", TFF=False, 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
# adjusting output color from: YUV444P16 to YUV422P10 for ProResModel
clip = core.resize.Bicubic(clip=clip, format=vs.YUV422P10, range_s="limited", dither_type="error_diffusion")
# set output frame rate to 59.94fps (progressive)
clip = core.std.AssumeFPS(clip=clip, fpsnum=60000, fpsden=1001)
# output
clip.set_output()

The script looks fine. Atm. it's using LWLibavSource, maybe try using a different source filter like Bestsource or FFmpegSource2.

Cu Selur

[Canayhands]

I cannot use vsviewer since I cannot find a package for it on linux, and changing the sources didn't fix it. If this is just a lost cause lol, then I get it.

[Selur]

vsViewer source is available over at: https://github.com/Selur/vsViewer
You could copy the script from the script view and copy it into vapoursynth-editor and test it there.
Could be that the dv file you have isn't supported by any of them.

Cu Selur

[Canayhands]

Thanks for the help, managed to get vsViewer working which returns this

Failed to evaluate the script:
Python exception: No module named 'qtgmc'
Traceback (most recent call last):
File "src/cython/vapoursynth.pyx", line 3387, in vapoursynth._vpy_evaluate
File "src/cython/vapoursynth.pyx", line 3388, in vapoursynth._vpy_evaluate
File "/tmp/tempPreviewVapoursynthFile19_30_54_274.vpy", line 11, in
import qtgmc
ModuleNotFoundError: No module named 'qtgmc'

And I definitely have qtgmc installed, so it definitely seems like it's one of those linux moments rather than anything wrong with any of the software itself. Thank you again.

[Canayhands]

Okay, fixed the qtgmc issue. Somehow, it was named qtgmc_h and it threw everything off.  But now I get this issue. In VapourSynth preview. 

Traceback (most recent call last):
File "src/cython/vapoursynth.pyx", line 3387, in vapoursynth._vpy_evaluate
File "src/cython/vapoursynth.pyx", line 3388, in vapoursynth._vpy_evaluate
File "/tmp/tempPreviewVapoursynthFile02_08_15_974.vpy", line 16, in
clip = core.lsmas.LWLibavSource(source="/home/jonah/Desktop/VIDEO/HVR/00_0001_0000-00-00_000000.DV", format="YUV411P8", stream_index=0, cache=0, prefer_hw=0)
^^^^^^^^^^
File "src/cython/vapoursynth.pyx", line 2895, in vapoursynth._CoreProxy.__getattr__
File "src/cython/vapoursynth.pyx", line 2701, in vapoursynth.Core.__getattr__
AttributeError: No attribute with the name lsmas exists. Did you mistype a plugin namespace or forget to install a plugin?

How fun, lol. And if I disable LWLIBAVSource, then I get the same error, but saying ffms2 doesn't exist.

[Selur]

Sounds like the Vapoursynth filter is missing.

Cu Selur

[Canayhands]

I have all the filters I can find installed. And now I'm either getting errors about lsmas failing to output a video frame. Due to how fragile the dependencies for this seem to be, this software just doesn't seem like it's a good fit for Linux unless it's distributed as a flatpak. But that's obviously extra work to benefit a small number of people. 

I'm just going to boot up my Windows install for whenever I need to use this instead.

[Selur]

If someone can write a script on how to build a flatpack with the dependencies, I'm happy to add it.
Other than that it's strange that Arch doesn't have the packages.

Cu Selur