Add feature to delay playback for a time while the receiver powers on

README.md

@@ -5,6 +5,7 @@ An MPD client to control Yamaha AV receivers with YNCA (network control) support
 ## Features
 
 * Powers the receiver on and switches input when playback starts.
+* Delays playback for a configurable time while the receiver powers on.
 * Switches sound program to a per-song choice, "Straight" for multi-channel songs, or some default.
 * Configurable using an INI file.
 

mpd-ynca.cpp

@@ -46,7 +46,7 @@ namespace po = boost::program_options;
 
 class YncaClient {
 public:
-	YncaClient(const std::string &host, const int port);
+	YncaClient(const std::string &host, const unsigned int port);
 	~YncaClient() = default;
 
 	std::string get_command(const std::string &command);
@@ -60,7 +60,7 @@ class YncaClient {
 	tcp::resolver::query resolver_query;
 };
 
-YncaClient::YncaClient(const std::string &host, const int port) :
+YncaClient::YncaClient(const std::string &host, const unsigned int port) :
 	io_service(),
 	socket(io_service),
 	resolver(io_service),
@@ -119,15 +119,17 @@ void YncaClient::with_connection(std::function<void ()> func) {
 	catch(...) {}
 }
 
-void connect_loop(YncaClient &ynca, const std::string &scene, const std::string &input, const optional<std::string> &default_program) {
+void connect_loop(YncaClient &ynca, const std::string &scene, const std::string &input, const optional<std::string> &default_program, std::chrono::seconds startup_delay) {
 	struct mpd_status *status = NULL;
 	enum mpd_state old_state, new_state;
 
+	unsigned int elapsed_ms;
 	const struct mpd_audio_format *format;
 	uint8_t	channels;
 
 	static const std::string \
-		on_cmd = "@MAIN:PWR=On", \
+		pwr_get_cmd = "@MAIN:PWR=?", \
+		pwr_on_cmd = "@MAIN:PWR=On", \
 		sound_prog_cmd = "@MAIN:SOUNDPRG=", \
 		straight_cmd = "@MAIN:STRAIGHT=On", \
 		input_get_cmd = "@MAIN:INP=?";
@@ -180,17 +182,40 @@ void connect_loop(YncaClient &ynca, const std::string &scene, const std::string
 			goto error;
 
 		new_state = mpd_status_get_state(status);
+		elapsed_ms = mpd_status_get_elapsed_ms(status);
 		format = mpd_status_get_audio_format(status);
 		channels = format ? format->channels : 0;
 		mpd_status_free(status);
 
 		if (new_state == MPD_STATE_PLAY) {
 			ynca.with_connection([&]() {
 				if (old_state != MPD_STATE_PLAY) {
-					// Power the receiver on and switch to the
-					// configured scene when playback starts.
-					ynca.put_command(on_cmd);
+					// When playback starts, check the power status.
+					bool was_off = ynca.get_command(pwr_get_cmd).find(pwr_on_cmd + "\r\n") == std::string::npos;
+
+					if (was_off) {
+						// If powered off, pause or stop the audio depending on
+						// the previous state, then power on. We don't pause
+						// unconditionally because MPD seems to chop off a
+						// little audio when unpausing, and this is most
+						// noticeable when playing a track from the start.
+						if (old_state == MPD_STATE_PAUSE) {
+							mpd_run_pause(conn, true);
+							mpd_run_seek_current(conn, elapsed_ms / 1000.f, false);
+						} else {
+							mpd_run_stop(conn);
+						}
+						ynca.put_command(pwr_on_cmd);
+					}
+
+					// Set the scene whether already powered on or not.
 					ynca.put_command(scene_put_cmd);
+
+					if (was_off) {
+						// If power was off, wait a bit, then resume audio.
+						std::this_thread::sleep_for(startup_delay);
+						mpd_run_play(conn);
+					}
 				} else if (ynca.get_command(input_get_cmd).find(input_put_cmd + "\r\n") == std::string::npos) {
 					// Stop playback if the input has changed.
 					mpd_run_stop(conn);
@@ -246,7 +271,7 @@ void connect_loop(YncaClient &ynca, const std::string &scene, const std::string
 	std::cerr << "MPD connection error: " << mpd_connection_get_error_message(conn) << std::endl;
 	mpd_connection_free(conn);
 	std::this_thread::sleep_for(std::chrono::seconds(1));
-	return connect_loop(ynca, scene, input, default_program);
+	return connect_loop(ynca, scene, input, default_program, startup_delay);
 }
 
 int main() {
@@ -256,10 +281,11 @@ int main() {
 
 	config.add_options()
 		("host", po::value<std::string>(), "Yamaha AV hostname")
-		("port", po::value<int>()->default_value(50000), "Yamaha AV port")
+		("port", po::value<unsigned int>()->default_value(50000), "Yamaha AV port")
 		("scene", po::value<std::string>(), "Yamaha AV scene for MPD")
 		("input", po::value<std::string>(), "Yamaha AV input for MPD")
 		("default-program", po::value(&default_program), "Yamaha AV default sound program name")
+		("startup-delay", po::value<unsigned int>()->default_value(5), "Startup delay")
 		;
 
 	const std::filesystem::path *cf = nullptr;
@@ -319,14 +345,15 @@ int main() {
 
 	YncaClient ynca = YncaClient(
 		vm["host"].as<std::string>(),
-		vm["port"].as<int>()
+		vm["port"].as<unsigned int>()
 	);
 
 	connect_loop(
 		ynca,
 		vm["scene"].as<std::string>(),
 		vm["input"].as<std::string>(),
-		default_program
+		default_program,
+		std::chrono::seconds(vm["startup-delay"].as<unsigned int>())
 	);
 
 	return EXIT_FAILURE;

ynca.conf

@@ -20,12 +20,18 @@ scene = Scene 1
 # Valid values include: HDMI1, AUDIO2, AV3
 input = HDMI1
 
-# The sound program to switch to by default when the song
-# changes. This can be overridden by setting the "ynca_program"
-# sticker against individual songs in the MPD media library.
-# Multi-channel songs will fall back to "Straight" mode instead. When
-# not defined, the entire sound program switching feature is disabled.
+# The sound program to switch to by default when the song changes. This can be
+# overridden by setting the "ynca_program" sticker against individual songs in
+# the MPD media library. Multi-channel songs will fall back to "Straight" mode
+# instead. When not defined, the entire sound program switching feature is
+# disabled.
 #
 # OPTIONAL
 # Valid values include: 7ch Stereo, 2ch Stereo, Hall in Munich
 default-program = 7ch Stereo
+
+# The amount of time in seconds to delay audio playback when the AV receiver
+# needs to be powered on.
+#
+# OPTIONAL
+startup-delay = 10