chad-music/back/utils.lisp

(in-package :cl-user)
(defpackage chad-music.utils
  (:use :cl #:audio-streams #:alexandria)
  (:export #:*standard-optimize-settings*
           #:text-tag
           #:bit-rate
           #:is-vbr
           #:duration
           #:publisher
           #:country))
(in-package :chad-music.utils)

(eval-when (:compile-toplevel :load-toplevel :execute)
  #+dbg
  (defvar *standard-optimize-settings* '(optimize (debug 3)))
  #-dbg
  (defvar *standard-optimize-settings* '(optimize (speed 3) (safety 0) (space 0) (debug 0))))

(defgeneric text-tag (stream desc) (:method ((object t) desc) nil))
(defmethod text-tag ((mp3 id3:mp3-file) desc)
  (declare #.*standard-optimize-settings*)

  (loop for frame in (id3:get-frames mp3 '("TXXX"))
     when (string-equal (id3:desc frame) desc)
     do (return-from text-tag (id3:val frame))))

(defgeneric bit-rate (stream) (:method ((object t)) nil))
(defgeneric is-vbr (stream) (:method ((object t)) nil))
(defgeneric duration (stream) (:method ((object t)) nil))
(defgeneric publisher (stream) (:method ((object t)) nil))
(defgeneric country (stream) (:method ((object t)) nil))
(defmethod bit-rate ((mp3 id3:mp3-file))
  (let ((info (id3:audio-info mp3)))
    (when info
      (round (mpeg::bit-rate info) 1000))))

(defmethod is-vbr ((mp3 id3:mp3-file))
  (let ((info (id3:audio-info mp3)))
    (when info
      (mpeg::is-vbr info))))

(defmethod duration ((mp3 id3:mp3-file))
  (let ((info (id3:audio-info mp3)))
    (when info
      (mpeg::len info))))

(defmethod publisher ((mp3 id3:mp3-file))
  (declare #.utils:*standard-optimize-settings*)

  (let ((frames (id3:get-frames mp3 '("TPUB" "TPB"))))
    (when frames
      (return-from publisher (id3:info (first frames)))))
  nil)

(defmethod country ((mp3 id3:mp3-file))
  (text-tag mp3 "MusicBrainz Album Release Country"))

(defmethod bit-rate ((m4a m4a:mp4-file))
  (let ((info (m4a:audio-info m4a)))
    (when info
      (round (m4a::avg-bit-rate info) 1000))))

(defmethod duration ((m4a m4a:mp4-file))
  (let ((info (m4a:audio-info m4a)))
    (when info
      (m4a::seconds info))))