use minimp3 instead of ffmpeg for MP3

README.md

@@ -2,7 +2,7 @@ libaudec
 ========
 
 libaudec (lib audio decoder) is a wrapper library
-over ffmpeg, sndfile and libsamplerate for reading
+over minimp3, sndfile and libsamplerate for reading
 and resampling audio files, based on Robin Gareus'
 `audio_decoder` code
 (https://github.com/x42/silan/tree/master/audio_decoder)
@@ -63,7 +63,7 @@ where specified, are licensed under different
 licenses.
 
 ----
-Copyright (C) 2019 Alexandros Theodotou
+Copyright (C) 2019-2020 Alexandros Theodotou
 
 Copying and distribution of this file, with or without modification,
 are permitted in any medium without royalty provided the copyright

inc/ad_plugin.h

@@ -1,4 +1,24 @@
 /*
+ * Copyright (C) 2020 Alexandros Theodotou <alex at zrythm dot org>
+ *
+ * This file is part of libaudec
+ *
+ * libaudec is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libaudec is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with libaudec.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
  * Copyright (C) 2011-2013 Robin Gareus <robin@gareus.org>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -83,4 +103,5 @@ ssize_t ad_read_null(void *, float*, size_t);
 /* hardcoded backends */
 const ad_plugin * adp_get_sndfile();
 const ad_plugin * adp_get_ffmpeg();
+const ad_plugin * adp_get_minimp3();
 #endif

meson.build

@@ -142,21 +142,22 @@ audec_cflags = cc.get_supported_arguments (
   audec_cflags)
 
 audec_deps = []
-libavcodec_dep = dependency (
-  'libavcodec', required: get_option ('ffmpeg'))
-libavformat_dep = dependency (
-  'libavformat', required: get_option ('ffmpeg'))
-libavutil_dep = dependency (
-  'libavutil', required: get_option ('ffmpeg'))
-audec_deps += [
-  libavcodec_dep,
-  libavformat_dep,
-  libavutil_dep,
-  ]
-have_ffmpeg = libavcodec_dep.found () and libavformat_dep.found () and libavutil_dep.found () and not get_option ('ffmpeg').disabled ()
-if have_ffmpeg
-  cdata.set('HAVE_FFMPEG', 1)
-endif
+#libavcodec_dep = dependency (
+  #'libavcodec', required: get_option ('ffmpeg'))
+#libavformat_dep = dependency (
+  #'libavformat', required: get_option ('ffmpeg'))
+#libavutil_dep = dependency (
+  #'libavutil', required: get_option ('ffmpeg'))
+#audec_deps += [
+  #libavcodec_dep,
+  #libavformat_dep,
+  #libavutil_dep,
+  #]
+#have_ffmpeg = libavcodec_dep.found () and libavformat_dep.found () and libavutil_dep.found () and not get_option ('ffmpeg').disabled ()
+#if have_ffmpeg
+  #cdata.set('HAVE_FFMPEG', 1)
+#endif
+have_ffmpeg = false
 
 audec_deps += [
   dependency('sndfile', version: '>=1.0.25'),
@@ -221,8 +222,6 @@ summary = [
   '',
   '  Build type: @0@'.format(
     get_option('buildtype')),
-  '  Optional libraries:',
-  '    ffmpeg: @0@'.format(have_ffmpeg),
   '  Directories:',
   '            prefix: @0@'.format(prefix),
   '        includedir: @0@'.format(includedir),

src/ad_minimp3.c

@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2020 Alexandros Theodotou <alex at zrythm dot org>
+ *
+ * This file is part of libaudec
+ *
+ * libaudec is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libaudec is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with libaudec.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+#include <math.h>
+
+#include "ad_plugin.h"
+
+#define MINIMP3_FLOAT_OUTPUT
+#define MINIMP3_IMPLEMENTATION
+#include "minimp3_ex.h"
+
+/* internal abstraction */
+
+typedef struct {
+  mp3dec_ex_t        dec_ex;
+} minimp3_audio_decoder;
+
+static void
+err_to_string (
+  int    err_code,
+  char * buf)
+{
+  switch (err_code)
+    {
+    case MP3D_E_PARAM:
+      strcpy (buf, "Parameter error");
+      break;
+    case MP3D_E_MEMORY:
+      strcpy (buf, "Memory error");
+      break;
+    case MP3D_E_IOERROR:
+      strcpy (buf, "IO error");
+      break;
+    case MP3D_E_USER:
+      strcpy (buf, "User error");
+      break;
+    case MP3D_E_DECODE:
+      strcpy (buf, "Decode error");
+      break;
+    default:
+      strcpy (buf, "Unknown error");
+      break;
+    }
+}
+
+static int
+ad_info_minimp3 (
+  void *      sf,
+  AudecInfo * nfo)
+{
+  minimp3_audio_decoder *priv =
+    (minimp3_audio_decoder*) sf;
+  if (!priv)
+    return -1;
+  if (nfo)
+    {
+      nfo->channels = priv->dec_ex.info.channels;
+      nfo->frames = priv->dec_ex.samples / nfo->channels;
+      nfo->sample_rate = priv->dec_ex.info.hz;
+      nfo->length =
+        nfo->frames ?
+        (nfo->frames * 1000) / nfo->sample_rate : 0;
+      nfo->bit_depth = 0;
+      nfo->bit_rate =
+        priv->dec_ex.info.bitrate_kbps;
+      nfo->meta_data = NULL;
+      nfo->bpm = 0;
+    }
+  return 0;
+}
+
+static void *
+ad_open_minimp3 (
+  const char * filename,
+  AudecInfo *  nfo)
+{
+  minimp3_audio_decoder *priv =
+    (minimp3_audio_decoder*)
+    calloc (1, sizeof(minimp3_audio_decoder));
+  int res =
+    mp3dec_ex_open (
+      &priv->dec_ex, filename, MP3D_SEEK_TO_SAMPLE);
+  if (res)
+    {
+      dbg (
+        AUDEC_DEBUG_LEVEL_ERROR,
+        "unable to open file '%s'.", filename);
+      char err_str[600];
+      err_to_string (res, err_str);
+      puts (err_str);
+      dbg (
+        AUDEC_DEBUG_LEVEL_ERROR, "error=%i", res);
+      free (priv);
+      return NULL;
+    }
+  ad_info_minimp3 (priv, nfo);
+  return (void*) priv;
+}
+
+static int
+ad_close_minimp3 (
+  void *sf)
+{
+  minimp3_audio_decoder *priv = (minimp3_audio_decoder*) sf;
+  if (!priv) return -1;
+  if (!sf)
+    {
+      dbg (0, "fatal: bad file close.\n");
+      return -1;
+    }
+  mp3dec_ex_close (&priv->dec_ex);
+  free (priv);
+  return 0;
+}
+
+static int64_t
+ad_seek_minimp3 (
+  void *sf, int64_t pos)
+{
+  minimp3_audio_decoder *priv = (minimp3_audio_decoder*) sf;
+  if (!priv) return -1;
+  return mp3dec_ex_seek (&priv->dec_ex, pos);
+}
+
+static ssize_t
+ad_read_minimp3 (
+  void *sf, float* d, size_t len)
+{
+  minimp3_audio_decoder *priv = (minimp3_audio_decoder*) sf;
+  if (!priv) return -1;
+  return mp3dec_ex_read (&priv->dec_ex, d, len);
+}
+
+static int ad_eval_minimp3(const char *f)
+{
+  char *ext = strrchr(f, '.');
+  if (strstr (f, "://")) return 0;
+  if (!ext) return 5;
+  if (!strcasecmp(ext, ".mp3")) return 100;
+  return 0;
+}
+
+static const ad_plugin ad_minimp3 = {
+#if 1
+  .eval = &ad_eval_minimp3,
+  .open = &ad_open_minimp3,
+  .close = &ad_close_minimp3,
+  .info = &ad_info_minimp3,
+  .seek = &ad_seek_minimp3,
+  .read = &ad_read_minimp3
+#else
+  &ad_eval_null,
+  &ad_open_null,
+  &ad_close_null,
+  &ad_info_null,
+  &ad_seek_null,
+  &ad_read_null
+#endif
+};
+
+/* dlopen handler */
+const ad_plugin * adp_get_minimp3() {
+  return &ad_minimp3;
+}
+

src/ad_plugin.c

@@ -89,12 +89,21 @@ choose_backend (
       plugin = adp_get_sndfile();
     }
 
+#if 0
   val = adp_get_ffmpeg()->eval(fn);
   if (val > max)
     {
       max = val;
       plugin = adp_get_ffmpeg();
     }
+#endif
+
+  val = adp_get_minimp3()->eval(fn);
+  if (val > max)
+    {
+      max = val;
+      plugin = adp_get_minimp3();
+    }
 
   return plugin;
 }

src/meson.build

@@ -17,6 +17,7 @@
 
 srcs = files ([
   'ad_soundfile.c',
-  'ad_ffmpeg.c',
+  #'ad_ffmpeg.c',
+  'ad_minimp3.c',
   'ad_plugin.c',
   ])

tests/meson.build

@@ -29,13 +29,11 @@ if get_option ('tests')
         meson.current_source_dir(), 'test.wav'),
       '44000',
       ])
-  if have_ffmpeg and get_option ('mp3_tests')
-    test (
-      'mp3_test', e,
-      args: [
-        join_paths (
-          meson.current_source_dir(), 'test.mp3'),
-        '48000',
-        ])
-  endif
+  test (
+    'mp3_test', e,
+    args: [
+      join_paths (
+        meson.current_source_dir(), 'test.mp3'),
+      '48000',
+      ])
 endif

tests/test.c

@@ -42,7 +42,7 @@ int main (
     {
       /*expected_frames_before = 294912;*/
       /* FIXME audacity says above */
-      expected_frames_before = 292654;
+      expected_frames_before = 291583;
       expected_sample_rate_before = 44100;
       expected_channels_before = 2;
     }