import os, subprocess, json, shutil

PATH_TO = '/path/to/files/' # директория с видео
NUMBER_OF_FRAMES = 20 # количество скриншотов

def create_snapshots(filename):

    print('Create snapshot to '+filename)

    #get video duration from FFprobe
    data = subprocess.Popen(
        ["ffprobe", "-v", "error", "-print_format", "json", "-show_entries", "format=duration",  PATH_TO+filename],
        stdout=subprocess.PIPE
        ).communicate()

    duration = json.loads(data[0].decode("utf-8"))['format']['duration']

    print('duration in sec: '+str(duration))
    now = round(float(duration))
    print('duration in format: '+str(now // 3600) + ':' + str(now // 60 % 60) + ':' + str(now % 60))

    interval = round(float(duration)/NUMBER_OF_FRAMES)-1
    print('interval: '+str(interval))

    #make snapshots folder
    tmp_v = PATH_TO+str(filename)+'s'
    if not os.path.exists(tmp_v):
        os.mkdir(tmp_v)

    for i in range(NUMBER_OF_FRAMES):
        now = interval*(i+1)
        time = str(now // 3600) + ':' + str(now // 60 % 60) + ':' + str(now % 60)
        FFMPEG_SNAPSHOT_COMMAND = 'ffmpeg -ss '+time+' -i '+PATH_TO+filename+' -vframes 1 -q:v 2 '+PATH_TO+filename+'s/'+str(i+1)+'.jpg -y'
        try:
            os.system(FFMPEG_SNAPSHOT_COMMAND)
            print('Build '+str(i+1)+'.jpg: OK')
        except:
            print('Build '+str(i+1)+'.jpg: ERROR')