the log doesn't contains ffmpeg output so we don't known why it exits
you can run this manually in a cmd window to see the full output:
"C:\Program Files (x86)\SVP 4\mpv64\mpv.exe" "E:/Anime/Your Lie in April/[AnimeKaizoku] Your Lie in April - 22 (720p 10bit x265 Dual Audio)[OED].mkv" --aid=1 --sid=no --no-sub-auto --o=- --input-ipc-server=mpvstreampipe --vf=vapoursynth:[C:\Users\jonni\AppData\Roaming\SVP4\scripts\fffe.py]:4:15 --ofps 60.000 --ovc=libx264 --ovfirst --ovcopts=b=9700000,preset=veryfast,g=60,keyint_min=60,refs=1,sc_threshold=0,threads=8 --oac=aac --of=matroska | "C:\Program Files (x86)\SVP 4\utils\ffmpeg.exe" -re -i - -map 0:? -codec:v copy -codec:a copy -bsf:v h264_mp4toannexb -f ssegment -segment_time 4 -segment_format mpegts -segment_list_size 10 -segment_list C:/Users/jonni/AppData/Local/Temp/svpcast/stream/svp.m3u8 -segment_start_number 0 -segment_list_flags +live C:/Users/jonni/AppData/Local/Temp/svpcast/stream/svp%04d.ts