m4a support

bcao.py

@@ -17,10 +17,15 @@ from zipfile import ZipFile
 from pathlib import Path
 from typing import Optional, Union, List, Dict
 
+# pycharm tells me some of these classes shouldn't be imported because they're not declared in __all__.
+# however, the mutagen docs show example code where someone creates a mutagen.flac.Picture by referring to it as
+#  Picture(), implying that they had imported mutagen.flac.Picture, and therefore i'm right and the computer is WRONG
+# https://mutagen.readthedocs.io/en/latest/api/flac.html#mutagen.Picture.data
 import mutagen
 from mutagen.flac import Picture, FLAC
 from mutagen.oggvorbis import OggVorbis
 from mutagen.mp3 import MP3
+from mutagen.mp4 import MP4, MP4Cover
 from mutagen.id3 import APIC, PictureType
 
 from PIL import Image
@@ -32,7 +37,14 @@ vorbis_to_id3: Dict[str, str] = {
 	"album": "TALB",
 	"album_artist": "TPE2"
 }
-fully_supported: List[str] = ["ogg", "flac", "mp3"]
+vorbis_to_itunes: Dict[str, str] = {
+	"track": 'trkn',
+	"artist": '\xa9ART',
+	"title": '\xa9nam',
+	"album": '\xa9alb',
+	"album_artist": 'aART'
+}
+fully_supported: List[str] = ["ogg", "flac", "mp3", "m4a"]
 MutagenFile = Union[MP3, FLAC, OggVorbis, mutagen.FileType]
 
 def log(message: str, importance: int = 0):
@@ -43,16 +55,34 @@ def die(message: str, code: int = 1):
 	print(message)
 	sys.exit(code)
 
-def get_tag(mut_song: MutagenFile, tag: str, allow_list: bool = False, allow_sanitising: bool = True) -> str:
+def get_tag(mut_song: MutagenFile, tag: str, allow_list: bool = False, allow_sanitising: bool = True)\
+		-> Union[str, List[str]]:
 	if isinstance(mut_song, MP3):
 		tag = vorbis_to_id3[tag]
-		tag_list = [str(x) for x in mut_song.tags.getall(tag)]
+		tag_list = mut_song.tags.getall(tag)
+
+	elif isinstance(mut_song, MP4):
+		# every tag in the MP4 file (from what i can tell) is a list
+		# this includes the track number tag, which is a list, containing a single tuple, containing two ints (track, total)
+		# unless we account for this, tag_list will be set to [(1, 5)], and then converted to a string, resulting in
+		#  ['(1, 5)'], which (if not allow_list) will be returned as '(1, 5)', which is not exactly helpful.
+		tag = vorbis_to_itunes[tag]
+		if tag == 'trkn':
+			# mut_song[tag] == [(1, 5)]
+			# mut_song[tag][0] == (1, 5)
+			tag_list = mut_song[tag][0]
+		else:
+			tag_list = mut_song[tag]
+
 	else:
 		if tag == "track":
 			tag = "tracknumber"
 		tag = tag.replace("_", "")
 		tag_list = mut_song[tag] if isinstance(mut_song[tag], list) else [mut_song[tag]]
 
+	# convert the list of strings/ID3 frames/ints/whatevers to strings
+	tag_list = list(map(str, tag_list))
+
 	# sanitise everything
 	if allow_sanitising:
 		tag_list = [sanitise(tag) for tag in tag_list]
@@ -76,7 +106,10 @@ def has_cover(mut_song: MutagenFile):
 				return True
 		return False
 
-	return False
+	if isinstance(mut_song, MP4):
+		return 'covr' in mut_song and len(mut_song['covr']) != 0
+
+	raise NotImplementedError("Song format not yet implemented.")
 
 def sanitise(in_str: str) -> str:
 	if args.sanitise:
@@ -88,7 +121,7 @@ parser = argparse.ArgumentParser(usage='%(prog)s zip [options]',
 	formatter_class=argparse.RawTextHelpFormatter,
 	description="Extracts the given zip file downloaded from Bandcamp and organises it.",
 	epilog=f"Cover art can only be embedded in files of the following types: {', '.join(fully_supported).upper()}.\nIf "
-	"the music is in any other format, %(prog)s will behave as though you passed the flag '-c n'.")
+	"the song is in any other format, %(prog)s will behave as though you passed '-c n', but will otherwise work normally.")
 parser.add_argument('zip', help='The zip file to use.')
 parser.add_argument('-c', '--add-cover-images', dest='process_cover', default='w', choices=['n', 'a', 'w'],
 	help="When to embed cover art into songs.\nOptions: [n]ever, [a]lways, [w]hen necessary.\nDefault: %(default)s")
@@ -166,6 +199,18 @@ if args.process_cover != 'n':
 		data = cover_file.read()
 
 	with Image.open(temp_cover) as image:
+		# it's really strange that the more annoying the file's metadata is, the *less* annoying it is to create cover art
+		#  for it in mutagen.
+		# vorbis: open standard, so easy to use that mutagen supplies a bunch of "easy" wrappers around other formats to
+		#  make them work more like mutagen.
+		#  cover-annoy-o-meter: high. mutagen requires you to specify the width, height, colour depth, etc etc
+		# id3: well documented, but rather cryptic (which is more understandable, "album_artist" or "TPE2").
+		#  cover-annoy-o-meter: not bad at all - at least you get a constructor this time - although it is kinda annoying
+		#  that you have to specify the file encoding, and how you need both a type and a desc.
+		# m4a: scarce documentation, closed format, half reverse engineered from whatever itunes is doing, exists pretty
+		#  much exclusively in the realm of apple stuff.
+		#  cover-annoy-o-meter: all you need is the file data and the format type.
+
 		if song_format in ["ogg", "flac"]:
 			# i hate this
 			embed_cover = Picture()
@@ -179,7 +224,7 @@ if args.process_cover != 'n':
 			# apparently APIC files get compressed on save if they are "large":
 			# https://mutagen.readthedocs.io/en/latest/api/id3_frames.html#mutagen.id3.APIC
 			# i don't know what that means (lossless text compression? automatic JPEG conversion?) and i don't know if or how
-			#  i can disable it, which kinda sucks...
+			# i can disable it, which kinda sucks...
 			# if, for example, mutagen's threshold for "large" is 200KiB, then any file over that size would be reduced to
 			# below it, either by resizing or JPEG quality reduction or whatever, making the -t flag useless for values above
 			#  200 when saving MP3 files.
@@ -199,6 +244,11 @@ if args.process_cover != 'n':
 				desc='cover',
 				data=data
 			)
+		elif song_format == "m4a":
+			embed_cover = MP4Cover(
+				data=data,
+				imageformat=MP4Cover.FORMAT_JPEG
+			)
 
 artists: List[str] = []
 album: Optional[str] = None
@@ -228,6 +278,8 @@ for song in song_names:
 			m.add_picture(embed_cover)
 		elif song_format == "mp3":
 			m.tags.add(embed_cover)
+		elif song_format == "m4a":
+			m['covr'] = [embed_cover]
 
 		m.save()