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MP3 ID3 Tags Code (41K) Article:3490 Link to this page Applies To: VB5 VB6 Author: Steve McMahon No logged bugs. 15 Apr 2004 Fixed incorrect download - the ID3v1 tag class incorrectly contained the code for the ID3v2 tags... Update History > Search WWW vbAccelerator	Reading and Writing MP3 ID3v1 and ID3v2 Tags Two classes to simplify MP3 Tag handling This article describes the MP3 ID3v1 and ID3v2 tags and provides a sample application which can read and write both types from MP3 files, along with two reusable classes wrapping up the tag functionality. About MP3 Tags The MP3 file standard includes specifications for tags, known as ID3 tags, which allow you to store information within the MP3 file about the track's title, artist and so on. If you're running Windows XP, you will see that there is a Shell Extension to read these tags, which allows you to read the tags in the Properties dialog for the file, or to see them in Explorer. There are two types of MP3 tags: the v1 original version, which is rather limited, and the v2 tags, which are much more sophisticated. ID3v1 Tags The ID3v1 tag is found at the end of an MP3 file and has a fixed number of fields and size. The structure of the tag is as follows: Private Type MP3ID3V1Tag Tag As String * 3 '-- 03 = "TAG" Title As String * 30 '-- 33 Artist As String * 30 '-- 63 Album As String * 30 '-- 93 Year As String * 4 '-- 97 Comment As String * 30 '-- 127 Genre As Byte '-- 128 End Type Note that v1.1 of the ID3v1 specification allows the last two bytes of the Comment tag to be used to store the track number. Byte 29 is always set to 0 in this case, and Byte 30 stores the track number itself. Checking if an MP3 file contains an ID3v1 tag is a simple matter of rewinding 128 bytes from the end and checking if the bytes read "TAG". If they do, then the rest of the bytes are the tag itself. Reading and writing the tag is simple: if its already there, then you just fill in the structure and then write it over the last 128 bytes of the file. If the tag isn't there, then just append a structure to the end of the file. For information, a list of known Genre bytes is given at the end of this article. The cMP3ID3v1 class provided with the download provides a wrapper for reading and writing this tag. Properties and methods are: MP3File - Gets/sets the MP3 file to work on. HasID3v1Tag - True if the MP3 file has an ID3v1 Tag, False otherwise. Title - Gets/sets the title. Use Update to save to the file. Album - Gets/sets the album. Use Update to save to the file. Year - Gets/sets the year. Use Update to save to the file. Genre - Gets/sets the genre. Use Update to save to the file. GenreName(genre As Byte) - Gets the genre name for the specified byte. Comments - Gets/sets the comment. Use Update to save to the file. Track - Gets/sets the track number. Use Update to save to the file. Update - Updates the MP3 file with the current values. All fields will be truncated so they are no longer than the length allowed in the structure prior to saving. ID3v2 Tags The ID3v2 tag is more flexible and hence more difficult to work with. An ID3v2 tag has a signature code of "ID3x" where x is the sub-version number of the tag. Typically ID3v2 tags are found at the beginning of an MP3 file but this is not an absolute restriction. What happens next depends on the subversion of the ID3v2 tag. As far as I can tell, there have been three versions so far: 2,3 and 4. Following the ID3v2 signature there are two reserved bytes and then 4 bytes containing the size of the ID3v2 tag. Note that all sizes appear in the opposite byte-order to Win32, so to read the actual length you need to swap the byte order. Once the size has been determined then anywhere after the header until the end of the tag there can be an ID3v2 tag Frame. The structure of a Frame header depends on the sub-version of ID3v2, but always encodes the name of the frame followed by its length in bytes and optionally some padding: ID3v2 subversion 2 Frame header Private Type ID3V22HDR frameName1 As String * 3 ' 3 frameSize1 As Byte ' 4 frameSize2 As Byte ' 5 frameSize3 As Byte ' 6 End Type ID3v2 subversion 3 or 4 Frame header Private Type ID3V23HDR sFrameName As String * 4 ' 4 lSize As Long ' 8 bPad1 As Byte ' 10 bPad2 As Byte ' 12 End Type Typical frame names used in the more modern ID3v2 tags are as follows (with the subversion 2 equivalent in brackets afterwards where I've found details): PCNT - Play counter TRCK - Track (ID3v2.2: TRK) TENC - Encoded by (ID3v2.2: TEN) WXXX - Link to TCOP - Copyright TOPE - Original artist TCOM - Composer TCON - Genre (ID3v2.2: TCO) COMM - Comment (ID3v2.2: COM) TYER - Year (ID3v2.2: TYE) TIT2 - Title (ID3v2.2: TT2) TRCK - Track number (ID3v2.2: TRK) TPE1 - Artist (ID3v2.2: TP1) TALB - Album (ID3v2.2: TAL) WOAF - Audio URL WOAR - Artist URL WCOM - Buy URL USLT - Lyrics It is possible to have more than one of each tag. For example, the COMM frame is used in MusicMatch to allow you tag Preferences, Notes, Bios, Moods, Tempos and other such trivial information. A different COMM frame is written out for each of these with the data within the COMM frames divided into a header (such as MusicMatch_Bio) followed by a null character and then the data. Clearly it is more difficult to read and write this member. If the file doesn't contain an ID3v2 tag, or the ID3v2 is too short for the new data, then the MP3 data has to be shifted up until it can be read in the result. I also noted that when writing some text frames, an additional null character is needed prior to the text otherwise the data isn't read correctly. The frames affected are Lyrics (USLT), Comments (COMM) and LinkTo (WXXX). The cMP3ID3v2 class provided with the download wraps up reading and writing this tag. There are two ways of using the class. For access to any of the standard frames given above, there are corresponding Property Gets/Lets. This does not allow you to create multiple COMM frames, though, so you can also work directly with the collection of frames. File Properties and Methods MP3File - Gets/sets the MP3 file to work on. HasID3v2Tag - True if the MP3 file has an ID3v2 Tag, False otherwise. Update - Updates the MP3 file with the current values. Standard Tag Properties and Methods Setting any of these properties will mean there will be only one occurrence of the relevant frame. For example, if you set the Comments property on an MP3 file that had multiple COMM frames, the old COMM frames are cleared and replaced with the new comment. Title - Gets/sets the title. Album - Gets/sets the album. Year - Gets/sets the year. Comments - Gets/sets the comment. Use Update to save to the file. Genre - Gets/sets the genre byte. GenreName(genre As Byte) - Gets the genre name for the specified byte. OtherGenreName - Gets sets the genre name. Track - Gets/sets the track number. Copyright - Gets/sets the copyright. OriginalArtist - Gets/sets the original artist. LinkTo - Gets/sets the LinkTo URL. Lyrics - Gets/sets the lyrics. EncodedBy - Gets/sets the encoder. ArtistURL - Gets/sets the artist URL. BuyURL - Gets/sets the Buy URL. AudioURL - Gets/sets the Audio URL. Frame Collection Properties and Methods FrameCount - Number of frames in the tag. Frame(index) - Gets the frame name (e.g. "COMM") for the specified frame index. RemoveFrame(frame) - Removes all the frames with the specified name (e.g. "COMM") or frame index. TagsInFrame(frame) - Returns the number of actual occurrences of the specified frame. AddTag(frame, tag) - Adds a new instance of the specified frame. RemoveTag(frame, tagIndex) - Removes the specified instance of a frame. Genre Bytes 34: Acid 74: Acid Jazz 73: Acid Punk 99: Acoustic 40: Alt.Rock 20: Alternative 26: Ambient 145: Anime 90: Avant Garde 116: Ballad 41: Bass 135: Beat 85: Bebob 96: Big Band 138: Black Metal 89: Blue Grass 0: Blues 107: Booty Bass 132: Brit Pop 65: Cabaret 88: Celtic 104: Chamber Music 102: Chanson 97: Chorus 136: Christian Gangsta Rap 61: Christian Rap 141: Christian Rock 1: Classic Rock 32: Classical 112: Club 128: Club - House 57: Comedy 140: Contemporary Christian 2: Country 139: Crossover 58: Cult 3: Dance 125: Dance Hall 50: Darkwave 22: Death Metal 4: Disco 55: Dream 127: Drum & Bass 122: Drum Solo 120: Duet 98: Easy Listening 52: Electronic 48: Ethnic 54: Eurodance 124: Euro - House 25: Euro - Techno 84: Fast Fusion 80: Folk 81: Folk / Rock 115: Folklore 119: Freestyle 5: Funk 30: Fusion 36: Game 59: Gangsta Rap 126: Goa 38: Gospel 49: Gothic 91: Gothic Rock 6: Grunge 79: Hard Rock 129: Hardcore 137: Heavy Metal 7: Hip Hop 35: House 100: Humour 131: Indie 19: Industrial 33: Instrumental 46: Instrumental Pop 47: Instrumental Rock 8: Jazz 29: Jazz - Funk 146: JPop 63: Jungle 86: Latin 71: Lo - fi 45: Meditative 142: Merengue 9: Metal 77: Musical 82: National Folk 64: Native American 133: Negerpunk 10: New Age 66: New Wave 39: Noise 11: Oldies 103: Opera 12: Other 75: Polka 134: Polsk Punk 13: Pop 62: Pop / Funk 53: Pop / Folk 109: Pr0n Groove 117: Power Ballad 23: Pranks 108: Primus 92: Progressive Rock 67: Psychedelic 93: Psychedelic Rock 43: Punk 121: Punk Rock 14: R&B 15: Rap 68: Rave 16: Reggae 76: Retro 87: Revival 118: Rhythmic Soul 17: Rock 78: Rock 'n'Roll 143: Salsa 114: Samba 110: Satire 69: Showtunes 21: Ska 111: Slow Jam 95: Slow Rock 105: Sonata 42: Soul 37: Sound Clip 24: Soundtrack 56: Southern Rock 44: Space 101: Speech 83: Swing 94: Symphonic Rock 106: Symphony 147: Synth Pop 113: Tango 18: Techno 51: Techno - Industrial 130: Terror 144: Thrash Metal 60: Top 40 70: Trailer 31: Trance 72: Tribal 27: Trip Hop 28: Vocal


	Home . VB . Code . vbMedia . Audio . Reading and Writing MP3 ID3v1 and ID3v2 Tags Copyright © 2004 Steve McMahon steve@vbaccelerator.com. All rights reserved. Last Updated: 18 April 2004