cl-madhl

CL-MADHL

cl-madhl is a package for common lisp that provides loadMP3, a function for reading an Mp3 file into PCM samples (possibly for playback with cl-alsa).

Authors

• Warren Wilkinson - wagwilk@telusplanet.net

History

Features

• Quite fast (but could be faster still, see HELP WANTED)
• Uses CFFI
• Tested on SBCL
• Only reads back in Mono
• Actually doesn't (yet) read the entire file, stops after something like 130000 samples (about 10 seconds). Thats all I needed.

Example Usage

(asdf:oos 'asdf:load-op :cl-alsa)
(asdf:oos 'asdf:load-op :cl-madhl)

BB(defpackage :mytest
  (:use :cl :cl-madhl :cl-alsa :trivial-gray-streams))

(in-package :mytest)

(defun play-mp3 ()
  (let* ((data (loadMP3 "test.mp3"))
         (samples (length data)))
    (format t "~%--- Playing ~s PCM samples" samples)
    (finish-output)
    (with-pcm-stream (pcm :data-format :snd-pcm-format-s16-le :mono :rate 44100)
      (stream-write-sequence pcm data 0 samples))
    (format t "~%done")))

(play-mp3)

Limitations

• Only reads them back in mono.
• No id3 tags.
• Only reads the first 10 seconds or so (not a bug, I put the limitation in there because I was lazy and didn't want to bother with EOF — I only needed some sample audio).

Download

• cl-madhl-0.0.1.tar.gz