mp3 m4a アートワーク カバー ジャケット 画像

import os

from mutagen.id3 import ID3
from mutagen.id3._frames import APIC  # type: ignore[reportPrivateImportUsage]
from mutagen.id3._util import ID3NoHeaderError  # type: ignore[reportPrivateImportUsage]
from mutagen.mp4 import MP4, MP4Cover


class EmbedCover:
    def embed(self, audio_path: str, image_path: str):
        ext = os.path.splitext(audio_path)[1]
        if ext == ".mp3":
            self.embed_cover_mp3(audio_path, image_path)
        elif ext == ".m4a":
            self.embed_cover_m4a(audio_path, image_path)

    def embed_cover_mp3(self, audio_path: str, image_path: str) -> None:
        try:
            tags = ID3(audio_path)
        except ID3NoHeaderError:
            tags = ID3()
            tags.save(audio_path)
            tags = ID3(audio_path)

        with open(image_path, "rb") as f:
            img = f.read()

        # MIME は JPEG か PNG に合わせる
        mime = "image/jpeg" if image_path.lower().endswith(".jpg") else "image/png"

        # 既存の画像タグを削除してから追加（重複防止）
        tags.delall("APIC")
        tags.add(
            APIC(
                encoding=3,  # UTF-8
                mime=mime,
                type=3,  # Cover (front)
                desc="Cover",
                data=img,
            )
        )
        tags.save(v2_version=3)  # ID3v2.3 で保存（互換性高い）

    def embed_cover_m4a(self, audio_path, image_path):
        audio = MP4(audio_path)
        with open(image_path, "rb") as f:
            img = f.read()
        # JPEGならFORMAT_JPEG、PNGならFORMAT_PNG
        audio["covr"] = [MP4Cover(img, imageformat=MP4Cover.FORMAT_JPEG)]
        audio.save()