taglib

Copyright (c) 2013, Mark VandenBrink. All rights reserved.

A pure Lisp implementation for reading MPEG-4 audio and MPEG-3 audio tags and audio information.

Mostly complete. Your mileage may vary. Most definitely, NOT portable. Heavily dependent on Clozure CCL.

Note: There a lot of good (some great) audio file resources out there. Here are a few of them that I found useful:

• l-smash: Exhaustively comprehensive MP4 box parser in C.
• taglib: Clean library in C++.
• mplayer: For me, the definitive tool on how to crack audio files.
• eyeD3: Great command line tool.
• MP3Diags: Good GUI-based-tool. Tends to slow, but very thorough.
• The MP4 Book: I actually didn't order this until well into writing this code. What a maroon. It would have saved me TONS of time.

Notes II:

• Depends on quicklisp packages: LOG5, and ALEXANDRIA. See taglib.asd.
• As the author(s) of taglib state in their comments, parsing ID3s is actually pretty hard. There are so many broken taggers out there that it is tough to compensate for all their errors.
• The parsing of MP3 audio properties (mpeg.lisp) is far from complete, especially when dealing with odd case WRT Xing headers.
• I've parsed just enough of the MP4 atoms/boxes to suit the needs of this tool. l-smash appears to parse all boxes. Maybe one day this lib will too.
• WRT error handling: in some cases, I've made them recoverable, but in general, I've went down the path of erroring out when I get problems.
• I've run this tool across my 19,000+ audio collection and compared the results to some of the tools above, with little to no variations. That said, I have a pretty uniform collection, mostly from ripping CDs, then iTunes purchases/matched, and the Amazon matched. YMMV
• Parsing the audio info in an MP3 is hideously inefficient and needs a rewrite (mpeg.lisp). There is a global parameter in audio-streams.lisp called get-audio-info that controls whether parse-mp4-file/parse-mp3-file try to extract this info. To speed things up, you can bind this this parameter to nil (eg: (let ((audio-streams:get-audio-info nil)) (parse-...)). As an example, when we're not getting audio-info, parsing an MP3 takes microsends. When we are, it takes seconds.

And now for some sample invocations and outputs:

(let (foo)
    (unwind-protect
        (setf foo (parse-mp4-file "01 Keep Yourself Alive.m4a"))
    (when foo (stream-close foo)))    ; make sure underlying open file is closed

	(mp4-tag:show-tags foo))

Yields:

01 Keep Yourself Alive.m4a
sample rate: 44100.0 Hz, # channels: 2, bits-per-sample: 16, max bit-rate: 314 Kbps, avg bit-rate: 256 Kbps, duration: 4:03
    album: Queen I
    album-artist: Queen
    artist: Queen
    compilation: no
    disk: (1 1)
    genre: 80 (Hard Rock)
    title: Keep Yourself Alive
    track: (1 11)
    year: 1973

The show-tags methods also have a "raw" capability. Example:

(let (foo)
    (unwind-protect
        (setf foo (parse-mp3-file "Queen/At the BBC/06 Great King Rat.mp3"))
    (when foo (stream-close foo)))    ; make sure underlying open file is closed

	(mp3-tag:show-tags foo :raw t))

Yields:

Queen/At the BBC/06 Great King Rat.mp3: MPEG 1, Layer III, VBR, sample rate: 44,100 Hz, bit rate: 128 Kbps, duration: 5:60
Header: version/revision: 3/0, flags: 0x00: 0/0/0/0, size = 11,899 bytes; No extended header; No V21 tag
    Frames[9]:
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 0, version = 3, id: TIT2, len: 15, NIL, encoding = 0, info = <Great King Rat>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 25, version = 3, id: TPE1, len: 6, NIL, encoding = 0, info = <Queen>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 41, version = 3, id: TPE2, len: 6, NIL, encoding = 0, info = <Queen>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 57, version = 3, id: TALB, len: 11, NIL, encoding = 0, info = <At the BBC>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 78, version = 3, id: TRCK, len: 4, NIL, encoding = 0, info = <6/8>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 92, version = 3, id: TPOS, len: 4, NIL, encoding = 0, info = <1/1>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 106, version = 3, id: TYER, len: 5, NIL, encoding = 0, info = <1995>
        frame-text-info: flags: 0x0000: 0/0/0/0/0/0, offset: 121, version = 3, id: TCON, len: 5, NIL, encoding = 0, info = <(79)>
        frame-txxx: flags: 0x0000: 0/0/0/0/0/0, offset: 136, version = 3, id: TXXX, len: 33, NIL, <Tagging time/2013-08-08T16:38:38>

I have a semi-complete logging strategy in place that is primarily used to figure out what happened when I get an unexpected error parsing a file. To see the output of ALL logging statements to STANDARD-OUTPUT, you can do the following:

(with-logging ()
    (test2::test2))

To see only the MP4-ATOM related logging stuff and redirect logging to to a file called "foo.txt":

(with-logging ("foo.txt" :categories (categories '(mp4-atom::cat-log-mp4-atom)))
    (taglib-tests::test2))

See logging.lisp for more info.

If you really want to create a lot of output, you can do the following:

(with-logging ("log.txt")
    (redirect "q.txt" (test2 :dir "somewhere-where-you-have-all-your-audio" :raw t)))

For my 19,000+ files, this generates 218,788,792 lines in "log.txt" and 240,727 lines in "q.txt".