Accessing parameters of TemporalDegrain2 in Hybrid

[Selur]

About the workflow:
1. ideally use a lossless format, when using x264 in lossy mode, you might want to use 10bit encoding.
2. "Using FFMPEG again to recombine the retouched PNG frames to the attached MP4." you are aware that you can load an image sequence into Hybrid right? (the ffmpeg step seem unnecessary)

Looking at the Avisynth step, the script seems fine:

ClearAutoloadDirs()
SetFilterMTMode("DEFAULT_MT_MODE", MT_MULTI_INSTANCE)
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\LoadDll.dll")
LoadDLL("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\d3d9.dll")
LoadDLL("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\libfftw3f-3.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\LSMASHSource.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\neo-dfttest.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\KNLMeansCL.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\dither.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\RgTools.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\mvtools2.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\FFT3dGPU.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\neo-fft3d.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\hqdn3d.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\masktools2.dll")
LoadPlugin("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\ConvertStacked.dll")
Import("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\mtmodes.avsi")
Import("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\TemporalDegrain2.avsi")
Import("C:\Program Files\Hybrid\64bit\Avisynth\avisynthPlugins\dither.avsi")
# loading source: E:\Daten\Filme\2025\KurzFilmFestival\Video\Footage\4_MP4_PR_GRN_RET\4_Retouched.mp4
# color sampling YV12@8, matrix: bt601, scantyp: progressive, luminance scale: limited
LWLibavVideoSource("E:\Daten\Filme\2025\KurzFilmFestival\Video\Footage\4_MP4_PR_GRN_RET\4_Retouched.mp4",cache=false,format="YUV420P8", prefer_hw=0,repeat=true)
# current resolution: 720x576
TemporalDegrain2(degrainTR=0,grainLevel=0,postSigma=0)
# setting output fps to 25.00000fps
AssumeFPS(25,1)
PreFetch(8)
#  output: color sampling YV12@8, matrix: bt601, scantyp: progressive, luminance scale: limited
return last

the encoding call:

"C:\Program Files\Hybrid\64bit\ffmpeg.exe" -y -loglevel fatal -noautorotate -nostdin -threads 8 -i "C:\Users\Thomas Mechau\AppData\Local\Temp\encodingTempSynthSkript_2025-11-28@12_38_47_1810_0.avs" -an -sn -pix_fmt yuv420p -fps_mode auto -r 25/1 -f rawvideo - | "C:\Program Files\Hybrid\64bit\x264.exe" --pass 1 --slow-firstpass --bitrate 24400 --profile high --level 5.1 --direct auto --b-adapt 0 --sync-lookahead 24 --qcomp 0.50 --qpmax 51 --partitions i4x4,p8x8,b8x8 --no-fast-pskip --subme 5 --trellis 0 --weightp 1 --aq-mode 0 --sar 16:15 --non-deterministic --range tv --stats "C:\Users\Thomas Mechau\AppData\Local\Temp\5_TemporalDegrain2_Avisynth_1_2025-11-28@12_38_47_1810_02.stats" --demuxer raw --input-res 720x576 --input-csp i420 --input-range tv --input-depth 8 --fps 25/1 --output-depth 8 --output "C:\Users\Thomas Mechau\AppData\Local\Temp\5_TemporalDegrain2_Avisynth_1.264" -

does seem to be fine too.
I would recommend to change temp-path to something outsice of 'AppData' and direct Windows folders and add an exemption to whatever virus scanner you are using.

According to the debug output the decoder crashes. So it either something with the script, Avisynth Preview should then show an error, or the deocidng call.
Please try:
a. does the Avisynth Preview work?
b. does enabling 'Config->Internals->Avisynth->Prefer FFmpeg as decoder' fix the problem?
If the Avisynth Preview already crashes, it might be a problem with one of the filters and your hardware setup. (I suspect it's fft3dgpu, since it's the only gpu filter that is really used with your settings and it's not used in Vapoursynth since it doesn't exist there.)
Using a similar script (same filters&co, different paths), I have no problems here.

My problem is the loss of detail in larger areas like the road surface, e.g. towards the end, top left. The subsequent MP2 coding for DVD authoring will remove even more small features, ...

a. for my taste you use too many loss encoding steps.
b. try adding CAS with 0.7 strength before the denoising; maybe even use it after the encoding in the first step,... (you need to adjust the filter order for this)
c. If you want to lower the strength of the degrain use another filter. I would use SMDegrain or MCDegrainSharp instead of TemporalDegrain2 on such a source, for my taste the source is not grainy enough to use TemporalDegrain2.
(personally, I would also use a deblocker and maybe denoise the darker areas a bit)

they suggest using outputStage and postMix, but these are not available in the GUI.

Personally, I never use outputStage, which is why it's not offered in the gui, since in my experience in those case where it might make sense, usually using another filter is a better approach. For a degrain filter, TemporalDegrain2 is a rather strong filter by design,...

Cu Selur