coub-dl/coub-dl.py

from subprocess import call, Popen, PIPE, check_output, DEVNULL, CalledProcessError
from os import listdir, remove
from os.path import splitext, exists, join
from re import match
from enum import Enum
from datetime import timedelta
from math import floor
from argparse import ArgumentParser
from functools import wraps
from tempfile import mkdtemp
from shutil import rmtree



class Stream(Enum):
    AUDIO = 1
    VIDEO = 2

class File(Enum):
    LIST = 1
    LOOP = 2
    FRACTION = 3
    OUTPUT = 4


def call_verbose(before_message='', after_message='Done!'):
    def tag(f):
        @wraps(f)
        def wrapper(*args, **kwargs):
            print_opt(before_message, end='', flush=True)
            f(*args, **kwargs)
            print_opt(after_message)
        return wrapper
    return tag


def print_opt(*args, **kwargs):
    if VERBOSE:
        print(*args, **kwargs)


def run(url, files_dict, directory):
    # download streams and update FILE dict with extensions
    download_audio_stream(url, files_dict)
    download_video_stream(url, files_dict)
    read_extensions(files_dict, directory)

    # get stream lengths via ffprobe
    audioLen = get_length(files_dict[Stream.AUDIO])
    videoLen = get_length(files_dict[Stream.VIDEO])

    # decide which stream needs some looping
    longer = audioLen if audioLen > videoLen else videoLen
    shorter = audioLen if audioLen < videoLen else videoLen
    shorterFile = files_dict[Stream.AUDIO] if audioLen < videoLen else files_dict[Stream.VIDEO]
    files_dict[File.LOOP] += splitext(shorterFile)[1]
    files_dict[File.FRACTION] += splitext(shorterFile)[1]

    # calculate how many times to loop
    times = longer.total_seconds() / shorter.total_seconds()
    timesLoop_base = floor(times)
    timesLoop_fraction = times % 1

    # write concat helper file for ffmpeg
    with open(files_dict[File.LIST], 'w') as f:
        for i in range(timesLoop_base):
            print("file '{}'".format(shorterFile), file=f)
        print("file '{}'".format(files_dict[File.FRACTION]), file=f)

    # loop & mux streams
    loop_shorter_stream(files_dict, shorter, shorterFile, timesLoop_fraction)
    mux_streams(files_dict)


@call_verbose(before_message='Downloading audio stream... ')
def download_audio_stream(url, file_dict):
    call(('youtube-dl', '--ignore-config',
                        '--extract-audio',
                        '--output', '{}.%(ext)s'.format(file_dict[Stream.AUDIO]),
          url),
         stdout=DEVNULL, stderr=DEVNULL)


@call_verbose(before_message='Downloading video stream... ')
def download_video_stream(url, file_dict):
    call(('youtube-dl', '--ignore-config',
                        '--output', '{}.%(ext)s'.format(file_dict[Stream.VIDEO]),
          url),
         stdout=DEVNULL, stderr=DEVNULL)


def read_extensions(file_dict, directory):
    for file in listdir(directory):
        for filename in file_dict:
            fullname = join(directory, file)
            if match('^{}.*'.format(file_dict[filename]), fullname):
                file_dict[filename] = fullname


def get_length(file):
    data = get_duration(get_command_stderr(('ffprobe', file))).split(':')
    return timedelta(hours=float(data[0]), minutes=float(data[1]), seconds=float(data[2]))


def get_command_stderr(command):
    process = Popen(command, stderr=PIPE, stdout=PIPE)
    out, err = process.communicate()
    return err


def get_duration(ffprobe_output):
    durationPattern = r'.*Duration:\s(.+),\sstart.*'
    regex = match(durationPattern, str(ffprobe_output))
    duration = regex.groups()[0] if regex else None
    if not duration:
        raise ValueError('Cannot process ffprobe output!')
    return duration


@call_verbose(before_message='Looping shorter stream... ')
def loop_shorter_stream(file_dict, shorter, shorter_file, loop_fraction):
    # prepare last fractional loop
    call(('ffmpeg', '-i', shorter_file, '-t', str(loop_fraction * shorter.total_seconds()), file_dict[File.FRACTION]),
         stdout=DEVNULL, stderr=DEVNULL)

    # concat them
    call(('ffmpeg', '-f', 'concat', '-safe', '0', '-i', file_dict[File.LIST],
                    '-c', 'copy', file_dict[File.LOOP]),
         stdout=DEVNULL, stderr=DEVNULL)


@call_verbose(before_message='Muxing streams... ')
def mux_streams(file_dict):
    call(('ffmpeg', '-i', file_dict[File.LOOP],
                    '-i', file_dict[Stream.AUDIO],
                    '-map', '0:v:0', '-map', '1:a:0',
                    '-c', 'copy', file_dict[File.OUTPUT]),
         stdout=DEVNULL, stderr=DEVNULL)


@call_verbose(before_message='Checking your system for youtube-dl and ffmpeg... ', after_message='Found both!')
def check_for_ytdl_and_ffmpeg():
    error_str = '\nNo {} found in PATH! coub-dl requires youtube-dl & ffmpeg.'
    ytdl_found = False
    ffmpeg_found = False
    try:
        check_output(('youtube-dl', '--version'))
        ytdl_found = True
    except (CalledProcessError, FileNotFoundError):
        pass
    try:
        check_output(('ffmpeg', '-version'))
        ffmpeg_found = True
    except (CalledProcessError, FileNotFoundError):
        pass

    if not ytdl_found and not ffmpeg_found:
        print_opt(error_str.format('youtube-dl nor ffmpeg'))
    elif not ytdl_found:
        print_opt(error_str.format('youtube-dl'))
    elif not ffmpeg_found:
        print_opt(error_str.format('ffmpeg'))

    if not ytdl_found or not ffmpeg_found: exit()


def determine_output_filename(url, user_supplied, extension, files_dict):
    if user_supplied is None:
        files_dict[File.OUTPUT] = check_output(('youtube-dl', '--get-title', url)).decode('utf-8').strip()
    else:
        files_dict[File.OUTPUT] = user_supplied
    files_dict[File.OUTPUT] += extension


def build_default_files_dict():
     return {Stream.AUDIO: 'audio', Stream.VIDEO: 'video',
             File.LIST: 'list.txt', File.LOOP: 'loop', File.FRACTION: 'fraction',
             File.OUTPUT: ''}, [File.OUTPUT]


def parse_cmd_arguments():
    parser = ArgumentParser(description='Download player-looped videos with youtube-dl & ffmpeg.')
    parser.add_argument('-nv', '--nonverbose', action='store_true', help='Turn off non-critical messages to user')
    parser.add_argument('-o', '--output', default=None, help='Specify name of the output file (use -e for extension)')
    parser.add_argument('-e', '--extension', default='mp4', help='Set the container to use for the output')
    parser.add_argument('url', type=str, help='The URL of the site containing the video to download')

    args = parser.parse_args()
    args.extension = '.' + args.extension

    return args


def yes_no_question(question, default):
    valid = {"yes": True, "y": True, "ye": True,
             "no": False, "n": False}
    if default is None:
        prompt = " [y/n] "
    elif default == "yes":
        prompt = " [Y/n] "
    elif default == "no":
        prompt = " [y/N] "
    else:
        raise ValueError("Invalid default answer: {}!".format(default))

    while True:
        print(question + prompt)
        choice = input().lower()
        if default is not None and choice == '':
            return valid[default]
        elif choice in valid:
            return valid[choice]
        else:
            print("Please respond with 'yes'(y) or 'no'(n)!")


# tempfile.TemporaryDirectory replacement to provide backwards compatibility
class temporary_directory:
    def __enter__(self):
        self.name = mkdtemp()
        return self.name

    def __exit__(self, exc_type, exc_val, exc_tb):
        rmtree(self.name)



if __name__ == '__main__':
    args = parse_cmd_arguments()
    VERBOSE = False if args.nonverbose else True

    check_for_ytdl_and_ffmpeg()

    # create dict that contains files used
    FILES, OUTPUT_KEYS = build_default_files_dict()
    URL = args.url

    determine_output_filename(URL, args.output, args.extension, FILES)

    # ask what to do if output exists
    if exists(FILES[File.OUTPUT]):
        answer = yes_no_question('A file named "{}" already exists! Overwrite?'.format(FILES[File.OUTPUT]),
                                 default='no')
        if not answer:
            print_opt('Exiting!')
            exit()
        else:
            remove(FILES[File.OUTPUT])

    # create temporary directory to work in
    with temporary_directory() as dir:
        # update temporary file locations in FILES dict
        for key in {key: FILES[key] for key in FILES if key not in OUTPUT_KEYS}:
            FILES[key] = join(dir, FILES[key])

        run(URL, FILES, dir)