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This is a quick script that helps me to convert MP3 files from my CDs into videos I can upload on YouTube. It is intended for personal use, so no input error checks. I am creating a silent video using OpenCV, combining MP3s using pydub, then put audio and video together using ffmpeg.

I am happy with the resulting videos. The code looks a bit naive, but introducing more complex structures is probably an overkill given the simplicity of the task.

This code is also on GitHub.

import os, codecs, datetime, glob
import cv2, pydub, PIL # these packages need to be installed
from PIL import ImageFont, ImageDraw

# get filenames with given extensions from a given directory and all directories inside it
def get_filenames_with_extensions_recursively(directory_name, extensions):
    result = [] 
    for extension in extensions:
        path_pattern = os.path.join(directory_name, '**', '*.' + extension)   
        result += glob.glob(path_pattern, recursive=True)
    return result

# Score function for default audio sorting: directory containing the file, 
# then the number of the track, then the name of the file
def default_func_sort_audio_files(audio_name):    
    try:
        audio_mediainfo = pydub.utils.mediainfo(audio_name).get('TAG', None)
        track_str = audio_mediainfo['track'] 
        track_nb_str = track_str.split('/')
        track_nb = int(track_nb_str[0]) 
    except:
        track_nb = -1
    return (os.path.dirname(audio_name), track_nb, os.path.basename(audio_name))  

# Resize image, add subtitles and save it. 
# Returns the filename of the resulting image (including the path)
def add_subtitles(image_filename, 
                  temp_folder,
                  width, 
                  height, 
                  subtitles, 
                  font, 
                  sub_colour, 
                  sub_bg_colour, 
                  sub_indent_x):

    # make a blank completely transparent image for the rectangle
    with PIL.Image.new('RGBA', (width, height), (0, 0, 0, 0)) as img2:
        # get a drawing context for it
        draw = PIL.ImageDraw.Draw(img2)

        # create the background coloured box
        max_length_subtitles = 0
        for subtitle in subtitles:
            sub_size = font.getsize(subtitle)
            if max_length_subtitles < sub_size[0]:
                max_length_subtitles = sub_size[0]
        sub_bg_right = max_length_subtitles + 2 * sub_indent_x
        if sub_bg_right > width:
            sub_bg_right = width
        sub_bg_top = height - len(subtitles) * 2 * font.size - sub_indent_x
        draw.rectangle(((0, sub_bg_top), (sub_bg_right, height)), fill = sub_bg_colour)    

        # add subtitles
        sub_indent_y = height
        for subtitle in reversed(subtitles):  
            sub_indent_y -=  2 * font.size
            draw.text((sub_indent_x, sub_indent_y), subtitle, sub_colour, font = font)

        with PIL.Image.open(image_filename) as img:
            img = img.resize((width, height), PIL.Image.ANTIALIAS)    
            img = img.convert("RGBA")

            # composite the two images together and save
            temp_image_filename \
                = os.path.join(temp_folder, 
                               os.path.basename(image_filename) + '_with_subs.png')
            with PIL.Image.alpha_composite(img, img2) as img_full:
                img_full.save(temp_image_filename) 
            return temp_image_filename   

# The main function. It creates the video with all audio files of a given directory
# All images with given extensions from the same directory are fetched. 
# While an audio track is being played, one image, with the subtitles, is shown.
# Images are shown in alphabetic order. 
# Audio tracks are sorted using 'func_sort_audio_files'
# Descriptions and subtitles are obtained using 'func_get_audio_description_subtitles'
# Outputs: a compilation video 
#          a text file that contains the description of the tracks that constitute the video
def make_video( directory_name, 
                func_get_audio_description_subtitles,
                video_title = None,
                artist_override = None,
                func_sort_audio_files = default_func_sort_audio_files,
                width = 1280, 
                height = 720, 
                sub_font_size = 32,
                sub_font_name = "/System/Library/Fonts/SFNSText.ttf", 
                sub_encoding = "unic", 
                sub_colour = (255, 255, 255),
                # 4th number in sub_bg_colour is for the degree of transparency, 0 - 255 range
                sub_bg_colour = (0, 0, 0, 128), 
                sub_indent_x = 10,
                description_intro = [''],
                file_encoding = 'utf-8', 
                image_extensions = ['jpg', 'png'],
                audio_extensions = ['mp3', 'wav'], 
                dry_run = False):

    start_time = datetime.datetime.now()

    # prepare the temp directory
    temp_folder = os.path.join(directory_name, 'temp')
    if not os.path.exists(temp_folder):
        os.makedirs(temp_folder)
    extensions_to_remove = image_extensions + audio_extensions
    if not dry_run:
        extensions_to_remove += ['mp4']
    filenames_to_remove = get_filenames_with_extensions_recursively(temp_folder, extensions_to_remove)
    for fn in filenames_to_remove:
        os.remove(fn)

    # get the filenames and sort them
    images_filenames = get_filenames_with_extensions_recursively(directory_name, image_extensions)
    images_filenames.sort() 
    audio_filenames =  get_filenames_with_extensions_recursively(directory_name, audio_extensions)
    audio_filenames.sort(key = lambda af: func_sort_audio_files(af))

    # initiate variables                 
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
    font = PIL.ImageFont.truetype(sub_font_name, sub_font_size, encoding = sub_encoding)  
    silent_video_name = os.path.join(temp_folder, os.path.basename(directory_name) + '_silent.mp4')
    video = cv2.VideoWriter(silent_video_name, fourcc, 1.0, (width, height))

    descriptions = description_intro
    audio = pydub.AudioSegment.silent(duration = 0)
    counter_audio = 0
    counter_seconds = 0

    for audio_name in audio_filenames:

        audio_mediainfo = {}
        try:
            audio_mediainfo = pydub.utils.mediainfo(audio_name).get('TAG', None)   
        except:
            pass

        if not ('title' in audio_mediainfo):
            track_name = os.path.basename(audio_name)
            # remove the extension
            track_name = track_name[:track_name.rfind('.')]
            audio_mediainfo['title'] = track_name

        if not ('artist' in audio_mediainfo):
            audio_mediainfo['artist'] = ''
        if (artist_override != None):  
            audio_mediainfo['artist'] = artist_override

        counter_audio += 1
        description, subtitles = func_get_audio_description_subtitles(counter_audio, audio_mediainfo)
        descriptions += [str(datetime.timedelta(seconds=counter_seconds)) + " " + description]

        if not dry_run:               
            image_filename = images_filenames[counter_audio % len(images_filenames)]             
            temp_image_filename = add_subtitles(  image_filename, 
                                                  temp_folder,
                                                  width, 
                                                  height, 
                                                  subtitles, 
                                                  font, 
                                                  sub_colour, 
                                                  sub_bg_colour, 
                                                  sub_indent_x)
            img2 = cv2.imread(temp_image_filename)
        else:
            img2 = None

        audio_piece = pydub.AudioSegment.from_mp3(audio_name)        
        limit_audio_length_so_far = counter_seconds + audio_piece.duration_seconds
        while (counter_seconds <= limit_audio_length_so_far):
            if not dry_run:
                # add the image to the video using PIL (adding by 1sec-long frames)  
                video.write(img2) 
            counter_seconds += 1

        if not dry_run: 
            audio += audio_piece
            # match the duration of audio and video so far
            audio += pydub.AudioSegment.silent(duration =  (counter_seconds * 1000.0 - len(audio))) 

    # Finalize the silent video              
    cv2.destroyAllWindows()
    video.release()

    # Define the filenames
    if video_title == None:
        video_title = os.path.basename(directory_name)
    descriptions_file_path = os.path.join(temp_folder, video_title + '.txt')
    compilation_audio_name = os.path.join(temp_folder, video_title + '.mp3')
    video_name             = os.path.join(temp_folder, video_title + '.mp4')
    ffmpeg_output_path     = os.path.join(temp_folder, video_title + '_ffmpeg.txt')

    if not dry_run:
        # dump the long mp3
        audio.export(compilation_audio_name, format = "mp3")   

        # combine audio and silent video into the final video
        ffmpeg_cmd = 'ffmpeg -i "' + silent_video_name + '" -i "' + compilation_audio_name \
                + '" -shortest -c:v copy -c:a aac -b:a 256k "' + video_name + '"' \
                + ' > "'+ ffmpeg_output_path + '" 2>&1'
        os.system(ffmpeg_cmd)   

    # Finalize and output the descriptions
    descriptions_len = 0
    for d_line in descriptions:
        descriptions_len += len(d_line)
    separator = "*" * 80    
    descriptions = [separator, 
                     "Directory: " + directory_name,
                     separator] \
                 + descriptions \
                 + [separator, 
                    "The length of the video is " + str(counter_seconds / 60.0) + " minute(s)",
                    "It should be under 202-205min (this is a pydub limitation)",
                    separator,
                    "Description is " + str(descriptions_len) + " characters long",
                    "It should be under 4500-5000 characters long (this is a youtube limitation)",
                    separator,
                    "Started " + str(start_time) + ", completed " + str(datetime.datetime.now()),
                    separator]
    for d_line in descriptions:
        print (d_line)
    with codecs.open(descriptions_file_path, 'w', encoding = file_encoding) as the_file:
        the_file.writelines(d_line + "\n" for d_line in (descriptions))

def get_audio_description_subtitles_simple(counter_audio, audio_mediainfo):
    title = audio_mediainfo['title'].strip().replace('\\', '')
    track_name = 'Track ' + str(counter_audio) + ": " + title
    artist_name = audio_mediainfo['artist'].strip()
    desc = track_name + " by " + artist_name
    return desc, [track_name, artist_name]

def dry_run_get_audio_description_subtitles_dry_run(counter_audio, audio_mediainfo):
    print(audio_mediainfo)   
    return "", ""

if __name__ == '__main__':
    make_video(   directory_name = os.path.expanduser('~/Music/LouisXIII copy'), 
                  #artist_override = 'Dalida',
                  func_get_audio_description_subtitles = get_audio_description_subtitles_simple,
                  description_intro = ['Intended for personal use. I own the CDs', ''],
                  dry_run = True)
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3
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import os, codecs, datetime, glob

E401 multiple imports on one line

Recommend you run $ flake8 and heed its advice, as PEP-8 asks for just one import per line. Use isort to organize them.

Each of your functions has lovely comments; thank you. Recommend you turn the one-sentence comments into docstrings.

The add_subtitles() function is maybe slightly long, and could be broken out into one or two helpers. The arg list is on the long side. Width + height could trivially be collapsed into size, but I wonder if some of the other attributes, like colour, might sensibly be defaulted from an object that has an add_subtitles() method.

        if max_length_subtitles < sub_size[0]:
            max_length_subtitles = sub_size[0]

A more pythonic way to express this would be to construct a list of font sizes, and then assign max( ... ) of those sizes.

Similarly, please assign sub_bg_right as max of two numbers.

It feels like much of this logic could sensibly be encapsulated within a sub_bg object.

        draw.text(..., font = font)

PEP-8 asks for spaces around = assignment, but no spaces around = keyword args: font=font.

Nice comments on make_video(). Again, it takes quite a few args. It feels like a subtitle object could encapsulate several of them. These args are trouble:

            description_intro = [''],
            file_encoding = 'utf-8', 
            image_extensions = ['jpg', 'png'],
            audio_extensions = ['mp3', 'wav'], 

Well, file_encoding is fine, just lose the extra blanks around = equals. But the lists are trouble. Now, I know you're not mutating them. But it's a gotcha, evaluating and binding a mutable list at function definition time. Don't get in the habit of doing that. Make it default to an immutable sequence, such as a (tuple), or use the usual idiom:

def foo(name, extensions=None):
    if extensions is None:
        extensions = ['jpg', 'png']

The point is to re-evaluate the assignment on each execution of foo(), rather than binding an immortal list just once.

if not os.path.exists(temp_folder):
    os.makedirs(temp_folder)

Feel free to save one line by specifying , exist_ok=True.

You could easily break out a few helpers from this function, for example the whole audio_filenames loop is naturally a helper function.

    if not ('artist' in audio_mediainfo):

That's fine, but testing if 'artist' not in audio_mediainfo: is slightly more pythonic.

    if (artist_override != None):  
  1. No need for ( extra parens ) in a python if.
  2. Please test is identity of the None singleton, rather than equality: if artist_override is not None:. Or, more simply: if artist_override:

    while (counter_seconds <= limit_audio_length_so_far):
    

No ( extra parens ) in a python while, please.

if video_title == None:

Please test is None.

                "It should be under 202-205min (this is a pydub limitation)",
                ...
                "It should be under 4500-5000 characters long (this is a youtube limitation)",

There are limits, but you're not telling me what they are. Put a stake in the ground, say 202 min. and 4500 char. and be done with it.

title = audio_mediainfo['title'].strip().replace('\\', '')

This is apparently sanitizing a filename, making it safe to open for write. That is, you are rejecting Known Bad unicode code points. I would be more convinced if you instead used maketrans and translate to accept Known Good characters.

You tend to accommodate long expressions with \ backwhack continuation characters. Consider using ( parens ) instead:

short_string = 'Hi!'
much_longer_string = ('This,'
                      ' that,'
                      ' and the other.')
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