get video fps using FFProbe

You can simply run this also, to get the video FPS, this will work on linux machines.

ffprobe -v quiet -show_streams -select_streams v:0 INPUT |grep "r_frame_rate"

This will print the video FPS:

ffprobe -v error -select_streams v -of default=noprint_wrappers=1:nokey=1 -show_entries stream=r_frame_rate file.mp4

Get the video FPS and print it to stdout: Saw the answer by @geo-freak and added it to get only the frame rate (remove the extra text).

ffprobe -v quiet -show_streams -select_streams v:0 input.mp4 |grep "r_frame_rate" | sed -e 's/r_frame_rate=//'

The answer by @o_ren seems more reasonable.

Python Function to do the same:

def get_video_frame_rate(filename):
result = subprocess.run(
    [
        "ffprobe",
        "-v",
        "error",
        "-select_streams",
        "v",
        "-of",
        "default=noprint_wrappers=1:nokey=1",
        "-show_entries",
        "stream=r_frame_rate",
        filename,
    ],
    stdout=subprocess.PIPE,
    stderr=subprocess.STDOUT,
)
result_string = result.stdout.decode('utf-8').split()[0].split('/')
fps = float(result_string[0])/float(result_string[1])
return fps

The accepted answer suggests using stream=r_frame_rate. This is okay if you only need a slightly rounded result. (30/1 instead of ~29.7)

For a Precise & Unrounded FPS, Divide Total Frames by Duration:

ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -print_format csv="p=0" input.mp4 | read frames && 
ffprobe -i input.mp4 -show_entries format=duration -v quiet -of csv="p=0" | read duration && 
echo $(($frames/$duration))
    >> 29.970094916135743

Duration of file:

ffprobe -i input.mp4 -show_entries format=duration -v quiet -of csv="p=0"
    >> 15.367000

Total frame count of file:

ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -print_format csv input.mp4
    >> 461