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-rw-r--r--src/replay_gain_state.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/src/replay_gain_state.c b/src/replay_gain_state.c
new file mode 100644
index 000000000..c14ff6e10
--- /dev/null
+++ b/src/replay_gain_state.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2003-2010 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "replay_gain_state.h"
+#include "pcm_volume.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <math.h>
+
+struct replay_gain_state {
+ float preamp, missing_preamp;
+
+ enum replay_gain_mode mode;
+
+ struct replay_gain_info *info;
+
+ float scale;
+};
+
+struct replay_gain_state *
+replay_gain_state_new(float preamp, float missing_preamp)
+{
+ struct replay_gain_state *state = g_new(struct replay_gain_state, 1);
+
+ state->preamp = preamp;
+ state->missing_preamp = missing_preamp;
+ state->mode = REPLAY_GAIN_OFF;
+ state->info = NULL;
+
+ return state;
+}
+
+void
+replay_gain_state_free(struct replay_gain_state *state)
+{
+ assert(state != NULL);
+
+ if (state->info != NULL)
+ replay_gain_info_free(state->info);
+
+ g_free(state);
+}
+
+static float
+calc_replay_gain_scale(float gain, float peak, float preamp)
+{
+ float scale;
+
+ if (gain == 0.0)
+ return (1);
+ scale = pow(10.0, gain / 20.0);
+ scale *= preamp;
+ if (scale > 15.0)
+ scale = 15.0;
+
+ if (scale * peak > 1.0) {
+ scale = 1.0 / peak;
+ }
+ return (scale);
+}
+
+static void
+replay_gain_state_calc_scale(struct replay_gain_state *state)
+{
+ assert(state != NULL);
+
+ if (state->mode == REPLAY_GAIN_OFF || state->info == NULL)
+ return;
+
+ const struct replay_gain_tuple *tuple =
+ &state->info->tuples[state->mode];
+
+ g_debug("computing ReplayGain scale with gain %f, peak %f",
+ tuple->gain, tuple->peak);
+
+ state->scale = calc_replay_gain_scale(tuple->gain, tuple->peak,
+ state->preamp);
+}
+
+void
+replay_gain_state_set_mode(struct replay_gain_state *state,
+ enum replay_gain_mode mode)
+{
+ assert(state != NULL);
+
+ if (mode == state->mode)
+ return;
+
+ state->mode = mode;
+
+ replay_gain_state_calc_scale(state);
+}
+
+void
+replay_gain_state_set_info(struct replay_gain_state *state,
+ const struct replay_gain_info *info)
+{
+ assert(state != NULL);
+
+ if (state->info != NULL)
+ replay_gain_info_free(state->info);
+
+ state->info = info != NULL
+ ? replay_gain_info_dup(info)
+ : NULL;
+
+ replay_gain_state_calc_scale(state);
+}
+
+void
+replay_gain_state_apply(const struct replay_gain_state *state,
+ void *buffer, size_t size,
+ const struct audio_format *format)
+{
+ assert(state != NULL);
+
+ if (state->mode == REPLAY_GAIN_OFF)
+ return;
+
+ float scale = state->info != NULL
+ ? state->scale : state->missing_preamp;
+ pcm_volume(buffer, size, format, pcm_float_to_volume(scale));
+}