1 files changed, 242 insertions, 0 deletions
diff --git a/src/filter/ReplayGainFilterPlugin.cxx b/src/filter/ReplayGainFilterPlugin.cxx
new file mode 100644
index 00000000..13c8a406
--- /dev/null
+++ b/src/filter/ReplayGainFilterPlugin.cxx
@@ -0,0 +1,242 @@
+/*
+ * Copyright (C) 2003-2013 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 "ReplayGainFilterPlugin.hxx"
+#include "FilterPlugin.hxx"
+#include "FilterInternal.hxx"
+#include "FilterRegistry.hxx"
+#include "audio_format.h"
+#include "replay_gain_info.h"
+#include "replay_gain_config.h"
+#include "mixer_control.h"
+#include "PcmVolume.hxx"
+
+extern "C" {
+#include "pcm_buffer.h"
+}
+
+#include <assert.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "replay_gain"
+
+class ReplayGainFilter final : public Filter {
+	/**
+	 * If set, then this hardware mixer is used for applying
+	 * replay gain, instead of the software volume library.
+	 */
+	struct mixer *mixer;
+
+	/**
+	 * The base volume level for scale=1.0, between 1 and 100
+	 * (including).
+	 */
+	unsigned base;
+
+	enum replay_gain_mode mode;
+
+	struct replay_gain_info info;
+
+	/**
+	 * The current volume, between 0 and a value that may or may not exceed
+	 * #PCM_VOLUME_1.
+	 *
+	 * If the default value of true is used for replaygain_limit, the
+	 * application of the volume to the signal will never cause clipping.
+	 *
+	 * On the other hand, if the user has set replaygain_limit to false,
+	 * the chance of clipping is explicitly preferred if that's required to
+	 * maintain a consistent audio level. Whether clipping will actually
+	 * occur depends on what value the user is using for replaygain_preamp.
+	 */
+	unsigned volume;
+
+	struct audio_format format;
+
+	struct pcm_buffer buffer;
+
+public:
+	ReplayGainFilter()
+		:mixer(nullptr), mode(REPLAY_GAIN_OFF),
+		volume(PCM_VOLUME_1) {
+		replay_gain_info_init(&info);
+	}
+
+	void SetMixer(struct mixer *_mixer, unsigned _base) {
+		assert(_mixer == NULL || (_base > 0 && _base <= 100));
+
+		mixer = _mixer;
+		base = _base;
+
+		Update();
+	}
+
+	void SetInfo(const struct replay_gain_info *_info) {
+		if (_info != NULL) {
+			info = *_info;
+			replay_gain_info_complete(&info);
+		} else
+			replay_gain_info_init(&info);
+
+		Update();
+	}
+
+	void SetMode(enum replay_gain_mode _mode) {
+		if (_mode == mode)
+			/* no change */
+			return;
+
+		g_debug("replay gain mode has changed %d->%d\n", mode, _mode);
+
+		mode = _mode;
+		Update();
+	}
+
+	/**
+	 * Recalculates the new volume after a property was changed.
+	 */
+	void Update();
+
+	virtual const audio_format *Open(audio_format &af, GError **error_r);
+	virtual void Close();
+	virtual const void *FilterPCM(const void *src, size_t src_size,
+				      size_t *dest_size_r, GError **error_r);
+};
+
+static inline GQuark
+replay_gain_quark(void)
+{
+	return g_quark_from_static_string("replay_gain");
+}
+
+void
+ReplayGainFilter::Update()
+{
+	if (mode != REPLAY_GAIN_OFF) {
+		float scale = replay_gain_tuple_scale(&info.tuples[mode],
+		    replay_gain_preamp, replay_gain_missing_preamp, replay_gain_limit);
+		g_debug("scale=%f\n", (double)scale);
+
+		volume = pcm_float_to_volume(scale);
+	} else
+		volume = PCM_VOLUME_1;
+
+	if (mixer != NULL) {
+		/* update the hardware mixer volume */
+
+		unsigned _volume = (volume * base) / PCM_VOLUME_1;
+		if (_volume > 100)
+			_volume = 100;
+
+		GError *error = NULL;
+		if (!mixer_set_volume(mixer, _volume, &error)) {
+			g_warning("Failed to update hardware mixer: %s",
+				  error->message);
+			g_error_free(error);
+		}
+	}
+}
+
+static Filter *
+replay_gain_filter_init(gcc_unused const struct config_param *param,
+			gcc_unused GError **error_r)
+{
+	return new ReplayGainFilter();
+}
+
+const audio_format *
+ReplayGainFilter::Open(audio_format &af, gcc_unused GError **error_r)
+{
+	format = af;
+	pcm_buffer_init(&buffer);
+
+	return &format;
+}
+
+void
+ReplayGainFilter::Close()
+{
+	pcm_buffer_deinit(&buffer);
+}
+
+const void *
+ReplayGainFilter::FilterPCM(const void *src, size_t src_size,
+			    size_t *dest_size_r, GError **error_r)
+{
+
+	*dest_size_r = src_size;
+
+	if (volume == PCM_VOLUME_1)
+		/* optimized special case: 100% volume = no-op */
+		return src;
+
+	void *dest = pcm_buffer_get(&buffer, src_size);
+	if (volume <= 0) {
+		/* optimized special case: 0% volume = memset(0) */
+		/* XXX is this valid for all sample formats? What
+		   about floating point? */
+		memset(dest, 0, src_size);
+		return dest;
+	}
+
+	memcpy(dest, src, src_size);
+
+	bool success = pcm_volume(dest, src_size,
+				  sample_format(format.format),
+				  volume);
+	if (!success) {
+		g_set_error(error_r, replay_gain_quark(), 0,
+			    "pcm_volume() has failed");
+		return NULL;
+	}
+
+	return dest;
+}
+
+const struct filter_plugin replay_gain_filter_plugin = {
+	"replay_gain",
+	replay_gain_filter_init,
+};
+
+void
+replay_gain_filter_set_mixer(Filter *_filter, struct mixer *mixer,
+			     unsigned base)
+{
+	ReplayGainFilter *filter = (ReplayGainFilter *)_filter;
+
+	filter->SetMixer(mixer, base);
+}
+
+void
+replay_gain_filter_set_info(Filter *_filter, const replay_gain_info *info)
+{
+	ReplayGainFilter *filter = (ReplayGainFilter *)_filter;
+
+	filter->SetInfo(info);
+}
+
+void
+replay_gain_filter_set_mode(Filter *_filter, enum replay_gain_mode mode)
+{
+	ReplayGainFilter *filter = (ReplayGainFilter *)_filter;
+
+	filter->SetMode(mode);
+}