20k frames are a mere 800s of a 25fps movie... how slow is cpu process ? afaik nvenc can only do mjpeg_cuvid for stitching images, it won't work with tiffs... e.g. ffmpeg -vsync 0 -hwaccel cuvid -c:v mjpeg_cuvid -framerate NN -i image_%04d.jpg -c:v h264_nvenc x.mp4... &rei