mp3のid3タグに悩まされる話 #id3v1の読み取り

2020年2月19日

Javascript テクノロジー プログラミング

t f B! P L
1つの作業を完了しないと、次の作業に進むことが出来ない、ユゲタです。 現在、mp3ファイルをjavascriptで扱っているシステムを作っているんですが、 mp3ファイルには、id3タグという、曲名やアーティスト名などを格納している領域があり、 ファイル名ではなく、ちゃんと音楽データを管理する仕組みがあります。   このid3タグを取り出すには、ファイルのバイナリデータから取り出すしか方法がないため、 javascriptでは、普段あまり行わない操作に戸惑いながら、データ取得をしたという話です。

id3タグについて

id3のバージョンは、今現在以下の4つが存在します。
id3v1 id3v2.2 id3v2.3 id3v2.4
id3というのが、タグデータの名称だとすると、v1はバージョン1でv2がバージョン2ということのようですが、v2.2,v2.3,v2.4は、バージョン2.2 , 2.3 , 2.4という事ではなく、idv2のメジャーバージョン2 , 3 , 4という事なのだそうです。 この時点で全く意味不明な感じですが、まあ、とりあえず、v1,v2,v3,v4という風に考えるのがいいそうです。 そして、これらのバージョンはv1とv2はそれぞれフォーマットが全く違っていて、v2のそれぞれのメジャーバージョンも、ヘッダのデータフォーマットが一緒だけど、内容はまるで違っているという曲者なのです。 詳しくは、下記にリンクをつけてる参考ページを見てもらえると説明されています。

id3v1の解析コード

とりあえず、まずは、idv3v1のデータを取得してみたいと思います。 mp3_id3 = (function(){ var LIB = function(){}; LIB.prototype.bin2str = function(arr){ var str = ""; for(var i in arr){ str += String.fromCharCode(arr[i]); } str = str.replace(/\u000f/g , ""); return str; }; // @ [0,1,2,3] LIB.prototype.size_bit = function(datas , bit){ var num = 0; for(var i=0; i<datas.length; i++){ var shift = (datas.length - 1 - i); if(shift){ num += datas[i] << (bit * shift); } else{ num += datas[i]; } } return num; }; LIB.prototype.getFrameKey = function(key){ for(var i in frame_arr){ if(frame_arr[i][0] === key){ return i; } else if(frame_arr[i][1] === key){ return i; } } return key; }; // LIB.prototype.getByteAt = function(iOffset) { // return data.charCodeAt(iOffset + dataOffset) & 0xFF; // }; var mp3_id3 = function(){}; mp3_id3.prototype.read = function(file , callback){ var reader = new FileReader(); reader.readAsArrayBuffer(file); reader.onload = (function(e){ var target = e.target; var res = this.v1(target.result , target.buffer); callback(res); }).bind(this); }; // ---------- // id3v1 mp3_id3.prototype.v1 = function(binary){ if(!binary){return null;} var data = (new Uint8Array(binary)).slice(-128); if (data[0] + data[1] + data[2] !== 220) {return null} var lib = new LIB(); return { header : { id : lib.bin2str(data.slice( 0, 0 + 3)), type : 1, version : (!data[127]) ? 0 : 1 }, frame : { title : this.v1_str(data.slice( 3, 3 + 30)), artist : this.v1_str(data.slice(33, 33 + 30)), album : this.v1_str(data.slice(63, 63 + 30)), year : lib.bin2str(data.slice(93, 93 + 4)), comment : this.v1_str(data.slice(97, 97 + 30)), track : data[126], genre : data[127] && typeof v1_genre[data[127]] !== "undefined" ? v1_genre[data[127]] : data[127] } }; }; mp3_id3.prototype.v1_str = function(data){ var txt = new TextDecoder("SJIS"); return txt.decode(data); } var PICTURE_TYPES = { "0": "Other", "1": "32x32 pixels 'file icon' (PNG only)", "2": "Other file icon", "3": "Cover (front)", "4": "Cover (back)", "5": "Leaflet page", "6": "Media (e.g. lable side of CD)", "7": "Lead artist/lead performer/soloist", "8": "Artist/performer", "9": "Conductor", A: "Band/Orchestra", B: "Composer", C: "Lyricist/text writer", D: "Recording Location", E: "During recording", F: "During performance", "10": "Movie/video screen capture", "11": "A bright coloured fish", //<--- WTF? "12": "Illustration", "13": "Band/artist logotype", "14": "Publisher/Studio logotype" }; //from: http://bitbucket.org/moumar/ruby-mp3info/src/tip/lib/mp3info/id3v2.rb //TODO: replace with something longer var TAGS = { AENC: "Audio encryption", APIC: "Attached picture", COMM: "Comments", COMR: "Commercial frame", ENCR: "Encryption method registration", EQUA: "Equalization", ETCO: "Event timing codes", GEOB: "General encapsulated object", GRID: "Group identification registration", IPLS: "Involved people list", LINK: "Linked information", MCDI: "Music CD identifier", MLLT: "MPEG location lookup table", OWNE: "Ownership frame", PRIV: "Private frame", PCNT: "Play counter", POPM: "Popularimeter", POSS: "Position synchronisation frame", RBUF: "Recommended buffer size", RVAD: "Relative volume adjustment", RVRB: "Reverb", SYLT: "Synchronized lyric/text", SYTC: "Synchronized tempo codes", TALB: "Album", TBPM: "BPM", TCOM: "Composer", TCON: "Genre", TCOP: "Copyright message", TDAT: "Date", TDLY: "Playlist delay", TENC: "Encoded by", TEXT: "Lyricist", TFLT: "File type", TIME: "Time", TIT1: "Content group description", TIT2: "Title", TIT3: "Subtitle", TKEY: "Initial key", TLAN: "Language(s)", TLEN: "Length", TMED: "Media type", TOAL: "Original album", TOFN: "Original filename", TOLY: "Original lyricist", TOPE: "Original artist", TORY: "Original release year", TOWN: "File owner", TPE1: "Artist", TPE2: "Band", TPE3: "Conductor", TPE4: "Interpreted, remixed, or otherwise modified by", TPOS: "Part of a set", TPUB: "Publisher", TRCK: "Track number", TRDA: "Recording dates", TRSN: "Internet radio station name", TRSO: "Internet radio station owner", TSIZ: "Size", TSRC: "ISRC (international standard recording code)", TSSE: "Software/Hardware and settings used for encoding", TYER: "Year", TXXX: "User defined text information frame", UFID: "Unique file identifier", USER: "Terms of use", USLT: "Unsychronized lyric/text transcription", WCOM: "Commercial information", WCOP: "Copyright/Legal information", WOAF: "Official audio file webpage", WOAR: "Official artist/performer webpage", WOAS: "Official audio source webpage", WORS: "Official internet radio station homepage", WPAY: "Payment", WPUB: "Publishers official webpage", WXXX: "User defined URL link frame" }; var TAG_MAPPING_2_2_to_2_3 = { BUF: "RBUF", COM: "COMM", CRA: "AENC", EQU: "EQUA", ETC: "ETCO", GEO: "GEOB", MCI: "MCDI", MLL: "MLLT", PIC: "APIC", POP: "POPM", REV: "RVRB", RVA: "RVAD", SLT: "SYLT", STC: "SYTC", TAL: "TALB", TBP: "TBPM", TCM: "TCOM", TCO: "TCON", TCR: "TCOP", TDA: "TDAT", TDY: "TDLY", TEN: "TENC", TFT: "TFLT", TIM: "TIME", TKE: "TKEY", TLA: "TLAN", TLE: "TLEN", TMT: "TMED", TOA: "TOPE", TOF: "TOFN", TOL: "TOLY", TOR: "TORY", TOT: "TOAL", TP1: "TPE1", TP2: "TPE2", TP3: "TPE3", TP4: "TPE4", TPA: "TPOS", TPB: "TPUB", TRC: "TSRC", TRD: "TRDA", TRK: "TRCK", TSI: "TSIZ", TSS: "TSSE", TT1: "TIT1", TT2: "TIT2", TT3: "TIT3", TXT: "TEXT", TXX: "TXXX", TYE: "TYER", UFI: "UFID", ULT: "USLT", WAF: "WOAF", WAR: "WOAR", WAS: "WOAS", WCM: "WCOM", WCP: "WCOP", WPB: "WPB", WXX: "WXXX" }; //pulled from http://www.id3.org/id3v2-00 and changed with a simple replace //probably should be an array instead, but thats harder to convert -_- var v1_genre = { "0": "Blues", "1": "Classic Rock", "2": "Country", "3": "Dance", "4": "Disco", "5": "Funk", "6": "Grunge", "7": "Hip-Hop", "8": "Jazz", "9": "Metal", "10": "New Age", "11": "Oldies", "12": "Other", "13": "Pop", "14": "R&B", "15": "Rap", "16": "Reggae", "17": "Rock", "18": "Techno", "19": "Industrial", "20": "Alternative", "21": "Ska", "22": "Death Metal", "23": "Pranks", "24": "Soundtrack", "25": "Euro-Techno", "26": "Ambient", "27": "Trip-Hop", "28": "Vocal", "29": "Jazz+Funk", "30": "Fusion", "31": "Trance", "32": "Classical", "33": "Instrumental", "34": "Acid", "35": "House", "36": "Game", "37": "Sound Clip", "38": "Gospel", "39": "Noise", "40": "AlternRock", "41": "Bass", "42": "Soul", "43": "Punk", "44": "Space", "45": "Meditative", "46": "Instrumental Pop", "47": "Instrumental Rock", "48": "Ethnic", "49": "Gothic", "50": "Darkwave", "51": "Techno-Industrial", "52": "Electronic", "53": "Pop-Folk", "54": "Eurodance", "55": "Dream", "56": "Southern Rock", "57": "Comedy", "58": "Cult", "59": "Gangsta", "60": "Top 40", "61": "Christian Rap", "62": "Pop/Funk", "63": "Jungle", "64": "Native American", "65": "Cabaret", "66": "New Wave", "67": "Psychadelic", "68": "Rave", "69": "Showtunes", "70": "Trailer", "71": "Lo-Fi", "72": "Tribal", "73": "Acid Punk", "74": "Acid Jazz", "75": "Polka", "76": "Retro", "77": "Musical", "78": "Rock & Roll", "79": "Hard Rock", "80": "Folk", "81": "Folk-Rock", "82": "National Folk", "83": "Swing", "84": "Fast Fusion", "85": "Bebob", "86": "Latin", "87": "Revival", "88": "Celtic", "89": "Bluegrass", "90": "Avantgarde", "91": "Gothic Rock", "92": "Progressive Rock", "93": "Psychedelic Rock", "94": "Symphonic Rock", "95": "Slow Rock", "96": "Big Band", "97": "Chorus", "98": "Easy Listening", "99": "Acoustic", "100": "Humour", "101": "Speech", "102": "Chanson", "103": "Opera", "104": "Chamber Music", "105": "Sonata", "106": "Symphony", "107": "Booty Bass", "108": "Primus", "109": "Porn Groove", "110": "Satire", "111": "Slow Jam", "112": "Club", "113": "Tango", "114": "Samba", "115": "Folklore", "116": "Ballad", "117": "Power Ballad", "118": "Rhythmic Soul", "119": "Freestyle", "120": "Duet", "121": "Punk Rock", "122": "Drum Solo", "123": "A capella", "124": "Euro-House", "125": "Dance Hall" }; var _frames = { // v2.2 "BUF" : "Recommended buffer size", "CNT" : "Play counter", "COM" : "Comments", "CRA" : "Audio encryption", "CRM" : "Encrypted meta frame", "ETC" : "Event timing codes", "EQU" : "Equalization", "GEO" : "General encapsulated object", "IPL" : "Involved people list", "LNK" : "Linked information", "MCI" : "Music CD Identifier", "MLL" : "MPEG location lookup table", "PIC" : "Attached picture", "POP" : "Popularimeter", "REV" : "Reverb", "RVA" : "Relative volume adjustment", "SLT" : "Synchronized lyric/text", "STC" : "Synced tempo codes", "TAL" : "Album/Movie/Show title", "TBP" : "BPM (Beats Per Minute)", "TCM" : "Composer", "TCO" : "Content type", "TCR" : "Copyright message", "TDA" : "Date", "TDY" : "Playlist delay", "TEN" : "Encoded by", "TFT" : "File type", "TIM" : "Time", "TKE" : "Initial key", "TLA" : "Language(s)", "TLE" : "Length", "TMT" : "Media type", "TOA" : "Original artist(s)/performer(s)", "TOF" : "Original filename", "TOL" : "Original Lyricist(s)/text writer(s)", "TOR" : "Original release year", "TOT" : "Original album/Movie/Show title", "TP1" : "Lead artist(s)/Lead performer(s)/Soloist(s)/Performing group", "TP2" : "Band/Orchestra/Accompaniment", "TP3" : "Conductor/Performer refinement", "TP4" : "Interpreted, remixed, or otherwise modified by", "TPA" : "Part of a set", "TPB" : "Publisher", "TRC" : "ISRC (International Standard Recording Code)", "TRD" : "Recording dates", "TRK" : "Track number/Position in set", "TSI" : "Size", "TSS" : "Software/hardware and settings used for encoding", "TT1" : "Content group description", "TT2" : "Title/Songname/Content description", "TT3" : "Subtitle/Description refinement", "TXT" : "Lyricist/text writer", "TXX" : "User defined text information frame", "TYE" : "Year", "UFI" : "Unique file identifier", "ULT" : "Unsychronized lyric/text transcription", "WAF" : "Official audio file webpage", "WAR" : "Official artist/performer webpage", "WAS" : "Official audio source webpage", "WCM" : "Commercial information", "WCP" : "Copyright/Legal information", "WPB" : "Publishers official webpage", "WXX" : "User defined URL link frame", // v2.3 "AENC" : "Audio encryption", "APIC" : "Attached picture", "COMM" : "Comments", "COMR" : "Commercial frame", "ENCR" : "Encryption method registration", "EQUA" : "Equalization", "ETCO" : "Event timing codes", "GEOB" : "General encapsulated object", "GRID" : "Group identification registration", "IPLS" : "Involved people list", "LINK" : "Linked information", "MCDI" : "Music CD identifier", "MLLT" : "MPEG location lookup table", "OWNE" : "Ownership frame", "PRIV" : "Private frame", "PCNT" : "Play counter", "POPM" : "Popularimeter", "POSS" : "Position synchronisation frame", "RBUF" : "Recommended buffer size", "RVAD" : "Relative volume adjustment", "RVRB" : "Reverb", "SYLT" : "Synchronized lyric/text", "SYTC" : "Synchronized tempo codes", "TALB" : "Album/Movie/Show title", "TBPM" : "BPM (beats per minute)", "TCOM" : "Composer", "TCON" : "Content type", "TCOP" : "Copyright message", "TDAT" : "Date", "TDLY" : "Playlist delay", "TENC" : "Encoded by", "TEXT" : "Lyricist/Text writer", "TFLT" : "File type", "TIME" : "Time", "TIT1" : "Content group description", "TIT2" : "Title/songname/content description", "TIT3" : "Subtitle/Description refinement", "TKEY" : "Initial key", "TLAN" : "Language(s)", "TLEN" : "Length", "TMED" : "Media type", "TOAL" : "Original album/movie/show title", "TOFN" : "Original filename", "TOLY" : "Original lyricist(s)/text writer(s)", "TOPE" : "Original artist(s)/performer(s)", "TORY" : "Original release year", "TOWN" : "File owner/licensee", "TPE1" : "Lead performer(s)/Soloist(s)", "TPE2" : "Band/orchestra/accompaniment", "TPE3" : "Conductor/performer refinement", "TPE4" : "Interpreted, remixed, or otherwise modified by", "TPOS" : "Part of a set", "TPUB" : "Publisher", "TRCK" : "Track number/Position in set", "TRDA" : "Recording dates", "TRSN" : "Internet radio station name", "TRSO" : "Internet radio station owner", "TSIZ" : "Size", "TSRC" : "ISRC (international standard recording code)", "TSSE" : "Software/Hardware and settings used for encoding", "TYER" : "Year", "TXXX" : "User defined text information frame", "UFID" : "Unique file identifier", "USER" : "Terms of use", "USLT" : "Unsychronized lyric/text transcription", "WCOM" : "Commercial information", "WCOP" : "Copyright/Legal information", "WOAF" : "Official audio file webpage", "WOAR" : "Official artist/performer webpage", "WOAS" : "Official audio source webpage", "WORS" : "Official internet radio station homepage", "WPAY" : "Payment", "WPUB" : "Publishers official webpage", "WXXX" : "User defined URL link frame" }; var header_arr = [ "id", "type", "version", "debug", "flg", "size" ]; var frame_arr = { "title" : ["TIT2", "TT2"], "artist" : ["TPE1", "TP1"], "album" : ["TALB", "TAL"], "year" : ["TYER", "TYE"], "comment" : ["COMM", "COM"], "track" : ["TRCK", "TRK"], "genre" : ["TCON", "TCO"], "picture" : ["APIC", "PIC"], "lyrics" : ["USLT", "ULT"] }; var _defaultShortcuts = ["title", "artist", "album", "track"]; return mp3_id3; })(); 無駄なデータも付与しているので、少し長めのコードになってしまいましたが、このライブラリをwebページのfileAPIと組み合わせると、id3v1のデータを取得できるようになっています。 使い方は、 var input = document.querySelector("input[type='file']"); for(var i=0; i<input.files.length; i++){ if(input.files[i].file.match(/\.mp3$/)){ new mp3_id3().read(input.files[i].file , function(data){ console.log(data); }); } } inputタグのファイルをmp3ファイルである場合に、1つずつ送ることで、ファイル別にid3タグ情報を取得してくれます。 ただし、現在のソースでは、v1しか認識しないので、今後v2.2 v2.3 v2.4を追加していかなければいけませんね。 全部完成したら、githubにアップしますね・・・ まだまだ、果てしないゴールです・・・

参考

https://ja.wikipedia.org/wiki/ID3タグ https://www.mp3tag.de/en/index.html

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