Need to create a video from a series of images. The video needs to have a low frame rate. This is the command I use to create the video.
ffmpeg.exe -r 2 -i image
Some players, like VLC, don't like low framerate videos.
Use
ffmpeg.exe -framerate 2 -i images/%3d.jpg -r 8 -c:v libx264 -pix_fmt yuvj420p output.mp4
Each frame will still last for 0.5 seconds but output rate is 8 which should play in VLC.