nvidia accelerated video encoding with ffmpeg

Following this page,

https://docs.nvidia.com/video-technologies/video-codec-sdk/12.0/ffmpeg-with-nvidia-gpu/index.html

the following encoding went at around 21 fps with the NVidia 1060 graphics card - 

ffmpeg -r 30 -start_number -003875 -f image2 -i "OpenSpace%06d.png" -c:v h264_nvenc ../filename.mp4

Using h265_nvenc gave codec not found error, but hevc_nvenc worked. That went at around 23 fps. Without acceleration, when using the "lossless" parameter, it was taking several seconds per frame. 0.2 fps or so.

Edit - apparently full hardware transcode with NVDEC and NVENC:

ffmpeg -hwaccel cuda -hwaccel_output_format cuda -i input.mp4 -c:v h264_nvenc -preset slow output.mp4

But apparently lower quality - https://stackoverflow.com/questions/44510765/gpu-accelerated-video-processing-with-ffmpeg