Yes, at least, that's what the log message suggests.  If I try to add quotes around the json property names and run the command at the top of the log directly on the command line, I get a bit further but then I get other errors (like having to add pel : 1 in the super_params json...

Yeah, it is generated by the SVP Manager, it contains :

# This script was generated by SVP 4 Manager.
# Check https://www.svp-team.com for more details.

import vapoursynth as vs
core = vs.get_core(threads=4)

core.std.LoadPlugin("/home/jucer/SVP4/plugins/libsvpflow1_vs64.so")
core.std.LoadPlugin("/home/jucer/SVP4/plugins/libsvpflow2_vs64.so")

clip = video_in

super_params     = "{scale:{up:0},gpu:1,rc:true}"
analyse_params   = "{main:{search:{coarse:{distance:-8,bad:{sad:2000,range:24}},type:2}},refine:[{thsad:250}]}"
smoothfps_params = "{gpuid:11,gpu_qn:2,rate:{num:2,den:1},algo:13,mask:{area:100},scene:{}}"

src_fps     = container_fps if container_fps>0.1 else 30
demo_mode   = 0
stereo_type = 0
nvof = 0

########## BEGIN OF base.py ##########
# This file is a part of SmoothVideo Project (SVP) ver.4
# This is NOT the full Vapoursynth script, all used variables are defined via
# JScript code that generates the full script text.

def interpolate(clip):
# input_um - original frame in 4:2:0
# input_m  - cropped and resized (if needed) frame
# input_m8 - input_m converted to 8-bit
    input_um = clip.resize.Point(format=vs.YUV420P8,dither_type="random")
    input_m = input_um
    input_m8 = input_m

    if nvof:
        smooth  = core.svp2.SmoothFps_NVOF(input_m,smoothfps_params,nvof_src=input_m8,src=input_um,fps=src_fps)
    else:
        super   = core.svp1.Super(input_m8,super_params)
        vectors = core.svp1.Analyse(super["clip"],super["data"],input_m8,analyse_params)
        smooth  = core.svp2.SmoothFps(input_m,super["clip"],super["data"],vectors["clip"],vectors["data"],smoothfps_params,src=input_um,fps=src_fps)


    if demo_mode==1:
        return demo(input_m,smooth)
    else:
        return smooth

if stereo_type == 1:
    lf = interpolate(core.std.CropRel(clip,0,(int)(clip.width/2),0,0))
    rf = interpolate(core.std.CropRel(clip,(int)(clip.width/2),0,0,0))
    smooth = core.std.StackHorizontal([lf, rf])
elif stereo_type == 2:
    lf = interpolate(core.std.CropRel(clip,0,0,0,(int)(clip.height/2)))
    rf = interpolate(core.std.CropRel(clip,0,0,(int)(clip.height/2),0))
    smooth = core.std.StackVertical([lf, rf])
else:
    smooth =  interpolate(clip)
########### END OF base.py ###########


smooth = smooth.resize.Point(format=vs.YUV420P8)

Hi everyone,

I'm using archlinux and I've installed SVP4 with the official installer, not the AUR package (but I've installed all dependencies manually).

When I try to transcode a video, the transcoding fails because of some python/json parsing issue.  Any idea what to look for?

Here's the output

10:46:47.760: ===== Starting mpv ======
10:46:47.760: Command line: /usr/bin/mpv /home/jucer/intro.original.mp4 --o=/home/jucer/intro.SVP.temporary.mkv --no-audio --no-sub --no-sub-auto --input-ipc-server=/tmp/mpvencodesocket --input-media-keys=no --no-msg-color --vf=vapoursynth:/home/jucer/.local/share/SVP4/scripts/ffff.py:4:4 --of=matroska --ovc=h264_nvenc --ovcopts=b=20005789,preset=slow,profile=high,rc=vbr_hq,maxrate=26007526,bufsize=40011578,time_base=1000/60000,threads=4
10:46:48.507: (+) Video --vid=1 (*) (h264 1920x1080 30.003fps)
10:46:48.507: Audio --aid=1 (*) (aac 2ch 44100Hz)
10:46:48.635: [vapoursynth] Script evaluation failed:
10:46:48.635: [vapoursynth] Python exception: SVSuper: invalid 'params' syntax: * Line 1, Column 2
10:46:48.635: [vapoursynth] Missing '}' or object member name
10:46:48.635: [vapoursynth]
10:46:48.635: [vapoursynth]
10:46:48.635: [vapoursynth] Traceback (most recent call last):
10:46:48.635: [vapoursynth] File "src/cython/vapoursynth.pyx", line 1956, in vapoursynth.vpy_evaluateScript
10:46:48.635: [vapoursynth] File "src/cython/vapoursynth.pyx", line 1957, in vapoursynth.vpy_evaluateScript
10:46:48.635: [vapoursynth] File "/home/jucer/local/share/SVP4/scripts/ffff.py", line 56, in <module>
10:46:48.635: [vapoursynth] smooth = interpolate(clip)
10:46:48.635: [vapoursynth] File "/home/jucer/.local/share/SVP4/scripts/ffff.py", line 37, in interpolate
10:46:48.635: [vapoursynth] super = core.svp1.Super(input_m8,super_params)
10:46:48.635: [vapoursynth] File "src/cython/vapoursynth.pyx", line 1862, in vapoursynth.Function.__call__
10:46:48.635: [vapoursynth] vapoursynth.Error: SVSuper: invalid 'params' syntax: * Line 1, Column 2
10:46:48.635: [vapoursynth] Missing '}' or object member name
10:46:48.635: [vapoursynth]
10:46:48.635: [vapoursynth]
10:46:48.647: (!!!) Intermediate file may be broken: /home/jucer/intro.SVP.temporary.mkv
10:46:48.647: ===== mpv exited with code 9 =====