NVEnc Preview

[Selur]

I just tried, it with:

F:\Hybrid\64bit\NVEncC.exe --avhw --input "C:\Users\Selur\Desktop\TestSubs-1.mp4" -c raw --output-csp yuv420 --output-depth 8 --output-format y4m --output - | F:\Hybrid\64bit\ffplay.exe -f yuv4mpegpipe -i -

and it worked without any issues.
Same with:

F:\Hybrid\64bit\NVEncC.exe --avhw --input "C:\Users\Selur\Desktop\TestSubs-1.mp4" -c raw --output-csp yuv420 --output-depth 8 --output-format raw --output - | F:\Hybrid\64bit\ffplay.exe -f rawvideo -pixel_format yuv420p -video_size 720x300 -i -

and

F:\Hybrid\64bit\NVEncC.exe --avhw --input "C:\Users\Selur\Desktop\TestSubs-1.mp4" -c raw --output-res 720x304 --output-csp yuv420 --output-depth 8 --output-format raw --output - | F:\Hybrid\64bit\ffplay.exe -f rawvideo -pixel_format yuv420p -video_size 720x304 -i -

Cu Selur

Ps.: can't get Vapoursynth working with your stream, works fine with mine that already is mod16.