Allow writing audio to a named pipe (fifo) instead of live device

Fixes #684

5 files changed, 39 insertions, 4 deletions

diff --git a/contrib/config-example b/contrib/config-example
index 275659f..d6186c4 100644
--- a/contrib/config-example
+++ b/contrib/config-example
@@ -50,6 +50,7 @@
 #ca_bundle = /etc/ssl/certs/ca-certificates.crt
 #gain_mul = 1.0
 #sample_rate = 44100
+#audio_pipe = /tmp/mypipe
 
 # Format strings
 #format_nowplaying_song = %t by %a on %l%r%@%s
diff --git a/contrib/pianobar.1 b/contrib/pianobar.1
index 196bbb2..0cdf6c8 100644
--- a/contrib/pianobar.1
+++ b/contrib/pianobar.1
@@ -180,6 +180,12 @@ Replacement for %@ in station format string. It's " @ " by default.
 Select audio quality.
 
 .TP
+.B audio_pipe = /path/to/fifo
+Stream decoded, raw audio samples to a pipe instead of the default audio device. Use
+.B sample_rate
+to enforce a fixed sample rate.
+
+.TP
 .B autoselect = {1,0}
 Auto-select last remaining item of filtered list. Currently enabled for station
 selection only.
diff --git a/src/player.c b/src/player.c
index 848d58b..d73b718 100644
--- a/src/player.c
+++ b/src/player.c
@@ -38,9 +38,11 @@ THE SOFTWARE.
 #include <string.h>
 #include <math.h>
 #include <stdint.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <assert.h>
 #include <arpa/inet.h>
+#include <sys/stat.h>
 
 #include <libavcodec/avcodec.h>
 #include <libavutil/avutil.h>
@@ -340,10 +342,30 @@ static bool openDevice (player_t * const player) {
 	aoFmt.rate = getSampleRate (player);
 	aoFmt.byte_format = AO_FMT_NATIVE;
 
-	int driver = ao_default_driver_id ();
-	if ((player->aoDev = ao_open_live (driver, &aoFmt, NULL)) == NULL) {
-		BarUiMsg (player->settings, MSG_ERR, "Cannot open audio device.\n");
-		return false;
+	int driver = -1;
+	if (player->settings->audioPipe) {
+		// using audio pipe
+		struct stat st;
+		if (stat (player->settings->audioPipe, &st)) {
+			BarUiMsg (player->settings, MSG_ERR, "Cannot stat audio pipe file.\n");
+			return false;
+		}
+		if (!S_ISFIFO (st.st_mode)) {
+			BarUiMsg (player->settings, MSG_ERR, "File is not a pipe, error.\n");
+			return false;
+		}
+		driver = ao_driver_id ("raw");
+		if ((player->aoDev = ao_open_file(driver, player->settings->audioPipe, 1, &aoFmt, NULL)) == NULL) {
+			BarUiMsg (player->settings, MSG_ERR, "Cannot open audio pipe file.\n");
+			return false;
+		}
+	} else {
+		// use driver from libao configuration
+		driver = ao_default_driver_id ();
+		if ((player->aoDev = ao_open_live (driver, &aoFmt, NULL)) == NULL) {
+			BarUiMsg (player->settings, MSG_ERR, "Cannot open audio device.\n");
+			return false;
+		}
 	}
 
 	return true;
diff --git a/src/settings.c b/src/settings.c
index bcb5dfc..7518177 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -125,6 +125,7 @@ void BarSettingsDestroy (BarSettings_t *settings) {
 	free (settings->npStationFormat);
 	free (settings->listSongFormat);
 	free (settings->fifo);
+	free (settings->audioPipe);
 	free (settings->rpcHost);
 	free (settings->rpcTlsPort);
 	free (settings->partnerUser);
@@ -182,6 +183,7 @@ void BarSettingsRead (BarSettings_t *settings) {
 	settings->inkey = strdup ("R=U!LH$O2B#");
 	settings->outkey = strdup ("6#26FRL$ZWD");
 	settings->fifo = BarGetXdgConfigDir (PACKAGE "/ctl");
+	settings->audioPipe = NULL;
 	assert (settings->fifo != NULL);
 	settings->sampleRate = 0; /* default to stream sample rate */
 
@@ -390,6 +392,9 @@ void BarSettingsRead (BarSettings_t *settings) {
 			} else if (streq ("fifo", key)) {
 				free (settings->fifo);
 				settings->fifo = BarSettingsExpandTilde (val, userhome);
+			} else if (streq ("audio_pipe", key)) {
+				free (settings->audioPipe);
+				settings->audioPipe = BarSettingsExpandTilde (val, userhome);
 			} else if (streq ("autoselect", key)) {
 				settings->autoselect = atoi (val);
 			} else if (streq ("sample_rate", key)) {
diff --git a/src/settings.h b/src/settings.h
index a4264a2..1a9b256 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -103,6 +103,7 @@ typedef struct {
 	char *listSongFormat;
 	char *fifo;
 	char *rpcHost, *rpcTlsPort, *partnerUser, *partnerPassword, *device, *inkey, *outkey, *caBundle;
+	char *audioPipe;
 	char keys[BAR_KS_COUNT];
 	int sampleRate;
 	BarMsgFormatStr_t msgFormat[MSG_COUNT];