player volume is adjusted in software

client/alsaPlayer.cpp

@@ -27,7 +27,14 @@
 
 using namespace std;
 
-Player::Player(const PcmDevice& pcmDevice, Stream* stream) : handle_(NULL), buff_(NULL), active_(false), stream_(stream), pcmDevice_(pcmDevice)
+Player::Player(const PcmDevice& pcmDevice, Stream* stream) :
+	handle_(NULL),
+	buff_(NULL),
+	active_(false),
+	stream_(stream),
+	pcmDevice_(pcmDevice),
+	volume_(1.0),
+	muted_(false)
 {
 }
 
@@ -184,9 +191,22 @@ void Player::worker()
 		snd_pcm_delay(handle_, &framesDelay);
 		chronos::usec delay((chronos::usec::rep) (1000 * (double) framesDelay / stream_->getFormat().msRate()));
 //		logO << "delay: " << framesDelay << ", delay[ms]: " << delay.count() / 1000 << "\n";
+		double volume = volume_;
+		if (muted_)
+			volume = 0.;
 
+		const msg::SampleFormat& sampleFormat = stream_->getFormat();
 		if (stream_->getPlayerChunk(buff_, delay, frames_))
 		{
+			if (volume < 1.0)
+			{
+				if (sampleFormat.bits == 8)
+					adjustVolume<int8_t>(buff_, frames_*sampleFormat.channels, volume);
+				else if (sampleFormat.bits == 16)
+					adjustVolume<int16_t>(buff_, frames_*sampleFormat.channels, volume);
+				else if (sampleFormat.bits == 32)
+					adjustVolume<int32_t>(buff_, frames_*sampleFormat.channels, volume);
+			}
 			if ((pcm = snd_pcm_writei(handle_, buff_, frames_)) == -EPIPE)
 			{
 				logE << "XRUN\n";
@@ -211,49 +231,14 @@ void Player::worker()
 
 void Player::setVolume(double volume)
 {
-	long min, max;
+	volume_ = volume;
-	snd_mixer_t *handle;
-	snd_mixer_selem_id_t *sid;
-	const char *selem_name = "Master";
-
-	snd_mixer_open(&handle, 0);
-	snd_mixer_attach(handle, pcmDevice_.name.c_str());
-	snd_mixer_selem_register(handle, NULL, NULL);
-	snd_mixer_load(handle);
-
-	snd_mixer_selem_id_alloca(&sid);
-	snd_mixer_selem_id_set_index(sid, 0);
-	snd_mixer_selem_id_set_name(sid, selem_name);
-	snd_mixer_elem_t* elem = snd_mixer_find_selem(handle, sid);
-
-	snd_mixer_selem_get_playback_volume_range(elem, &min, &max);
-	snd_mixer_selem_set_playback_volume_all(elem, volume * max);
-
-	snd_mixer_close(handle);
 }
 
 
 
 void Player::setMute(bool mute)
 {
-	snd_mixer_t *handle;
+	muted_ = mute;
-	snd_mixer_selem_id_t *sid;
-	const char *selem_name = "Master";
-
-	snd_mixer_open(&handle, 0);
-	snd_mixer_attach(handle, pcmDevice_.name.c_str());
-	snd_mixer_selem_register(handle, NULL, NULL);
-	snd_mixer_load(handle);
-
-	snd_mixer_selem_id_alloca(&sid);
-	snd_mixer_selem_id_set_index(sid, 0);
-	snd_mixer_selem_id_set_name(sid, selem_name);
-	snd_mixer_elem_t* elem = snd_mixer_find_selem(handle, sid);
-
-	if (snd_mixer_selem_has_playback_switch(elem))
-		snd_mixer_selem_set_playback_switch_all(elem, mute?0:1);
-
-	snd_mixer_close(handle);
 }
 
 

client/alsaPlayer.h

@@ -28,15 +28,23 @@
 #include "pcmDevice.h"
 
 
+/// Audio Player
+/**
+ * Audio player implementation using Alsa
+ */
 class Player
 {
 public:
 	Player(const PcmDevice& pcmDevice, Stream* stream);
 	virtual ~Player();
+
+	/// Set audio volume in range [0..1]
 	void setVolume(double volume);
 	void setMute(bool mute);
 	void start();
 	void stop();
+
+	/// List the system's audio output devices
 	static std::vector<PcmDevice> pcm_list(void);
 
 private:
@@ -44,6 +52,14 @@ private:
 	void uninitAlsa();
 	void worker();
 
+	template <typename T>
+	void adjustVolume(char *buffer, size_t count, double volume)
+	{
+		T* bufferT = (T*)buffer;
+		for (size_t n=0; n<count; ++n)
+			bufferT[n] *= volume;
+	}
+
 	snd_pcm_t* handle_;
 	snd_pcm_uframes_t frames_;
 
@@ -52,6 +68,8 @@ private:
 	Stream* stream_;
 	std::thread playerThread_;
 	PcmDevice pcmDevice_;
+	double volume_;
+	bool muted_;
 };
 
 

client/controller.cpp

@@ -180,7 +180,7 @@ void Controller::worker()
 			stream_->setBufferLen(serverSettings->bufferMs - latency_);
 
 			player_.reset(new Player(pcmDevice_, stream_));
-			player_->setVolume(serverSettings->volume);
+			player_->setVolume(serverSettings->volume / 100.);
 			player_->start();
 
 			msg::Command startStream("startStream");