random_video_thumbnail.py

#!/usr/bin/env python3

"""
Searches for video files and generate a random picture from video.

ffmpeg is required
"""

import random
from pathlib import Path
from subprocess import Popen, DEVNULL, PIPE


def thumbnail(video):
    picture = video.with_suffix('.jpg')
    picture.unlink(missing_ok=True)
    duration = Popen(
        [
            'ffprobe', '-show_entries', 'format=duration',
            '-of', 'default=noprint_wrappers=1:nokey=1',
            '-i', video
        ],
        encoding='utf8',
        stderr=DEVNULL,
        stdout=PIPE).communicate()[0]
    rnd_duration = random.random() * float(duration)
    mm, ss = divmod(rnd_duration, 60)
    hh, mm = divmod(mm, 60)
    seek = f'{hh:.0f}:{mm:.0f}:{ss:.3f}'
    Popen(
        [
           'ffmpeg', '-ss', seek, '-i', video,
           '-frames:v', '1',
           str(picture),
        ],
        stderr=DEVNULL,
        stdout=DEVNULL).wait()
    return picture


def make_thumbnails(root, extensions, recursive=False):
    if recursive:
        ext_gen = (root.rglob(f'*.{ext}') for ext in set(extensions))
    else:
        ext_gen = (root.glob(f'*.{ext}') for ext in set(extensions))
    for ext in ext_gen:
        for video in ext:
            picture = thumbnail(video)
            if picture.exists():
                yield picture


if __name__ == '__main__':
    import shutil
    from argparse import ArgumentParser
    from argparse import ArgumentDefaultsHelpFormatter
    if not shutil.which('ffmpeg'):
        raise SystemExit('ffmpeg not found on your system')
    default_ext = 'mkv'
    available_exts = ('mkv', 'avi', 'mp4', 'ogg', 'mpg')
    parser = ArgumentParser(description=__doc__, formatter_class=ArgumentDefaultsHelpFormatter)
    parser.add_argument('root', type=Path, help='Root directory to search')
    parser.add_argument('-r', '--recursive', action='store_true', help='Recursive')
    parser.add_argument(
        '--extensions', nargs='+',
        choices=available_exts,
        default=[default_ext],
        help='File extensions of videos')
    args = parser.parse_args()
    for picture in make_thumbnails(**vars(args)):
        print(picture)