Add audio resampling

Fixes #683

5 files changed, 21 insertions, 3 deletions

diff --git a/contrib/config-example b/contrib/config-example
index 0229595..275659f 100644
--- a/contrib/config-example
+++ b/contrib/config-example
@@ -49,6 +49,7 @@
 #volume = 0
 #ca_bundle = /etc/ssl/certs/ca-certificates.crt
 #gain_mul = 1.0
+#sample_rate = 44100
 
 # Format strings
 #format_nowplaying_song = %t by %a on %l%r%@%s
diff --git a/contrib/pianobar.1 b/contrib/pianobar.1
index 7462030..196bbb2 100644
--- a/contrib/pianobar.1
+++ b/contrib/pianobar.1
@@ -368,6 +368,10 @@ variable. Only "Basic" http authentication is supported.
 .B rpc_tls_port = 443
 
 .TP
+.B sample_rate = 0
+Force fixed output sample rate. The default, 0, uses the stream’s sample rate.
+
+.TP
 .B sort = {name_az, name_za, quickmix_01_name_az, quickmix_01_name_za, quickmix_10_name_az, quickmix_10_name_za}
 Sort station list by name or type (is quickmix) and name. name_az for example
 sorts by name from a to z, quickmix_01_name_za by type (quickmix at the
diff --git a/src/player.c b/src/player.c
index 17fe7ed..848d58b 100644
--- a/src/player.c
+++ b/src/player.c
@@ -254,6 +254,15 @@ static bool openStream (player_t * const player) {
 	return true;
 }
 
+/*	Get output sample rate. Default to stream sample rate
+ */
+static int getSampleRate (const player_t * const player) {
+	AVCodecParameters const * const cp = player->st->codecpar;
+	return player->settings->sampleRate == 0 ?
+			cp->sample_rate :
+			player->settings->sampleRate;
+}
+
 /*	setup filter chain
  */
 static bool openFilter (player_t * const player) {
@@ -289,8 +298,8 @@ static bool openFilter (player_t * const player) {
 
 	/* aformat: convert float samples into something more usable */
 	AVFilterContext *fafmt = NULL;
-	snprintf (strbuf, sizeof (strbuf), "sample_fmts=%s",
-			av_get_sample_fmt_name (avformat));
+	snprintf (strbuf, sizeof (strbuf), "sample_fmts=%s:sample_rates=%d",
+			av_get_sample_fmt_name (avformat), getSampleRate (player));
 	if ((ret = avfilter_graph_create_filter (&fafmt,
 					avfilter_get_by_name ("aformat"), "format", strbuf, NULL,
 					player->fgraph)) < 0) {
@@ -328,7 +337,7 @@ static bool openDevice (player_t * const player) {
 	aoFmt.bits = av_get_bytes_per_sample (avformat) * 8;
 	assert (aoFmt.bits > 0);
 	aoFmt.channels = cp->channels;
-	aoFmt.rate = cp->sample_rate;
+	aoFmt.rate = getSampleRate (player);
 	aoFmt.byte_format = AO_FMT_NATIVE;
 
 	int driver = ao_default_driver_id ();
diff --git a/src/settings.c b/src/settings.c
index 4ee1bd6..bcb5dfc 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -183,6 +183,7 @@ void BarSettingsRead (BarSettings_t *settings) {
 	settings->outkey = strdup ("6#26FRL$ZWD");
 	settings->fifo = BarGetXdgConfigDir (PACKAGE "/ctl");
 	assert (settings->fifo != NULL);
+	settings->sampleRate = 0; /* default to stream sample rate */
 
 	settings->msgFormat[MSG_NONE].prefix = NULL;
 	settings->msgFormat[MSG_NONE].postfix = NULL;
@@ -391,6 +392,8 @@ void BarSettingsRead (BarSettings_t *settings) {
 				settings->fifo = BarSettingsExpandTilde (val, userhome);
 			} else if (streq ("autoselect", key)) {
 				settings->autoselect = atoi (val);
+			} else if (streq ("sample_rate", key)) {
+				settings->sampleRate = atoi (val);
 			} else if (strncmp (formatMsgPrefix, key,
 					strlen (formatMsgPrefix)) == 0) {
 				static const char *mapping[] = {"none", "info", "nowplaying",
diff --git a/src/settings.h b/src/settings.h
index 709a56f..a4264a2 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -104,6 +104,7 @@ typedef struct {
 	char *fifo;
 	char *rpcHost, *rpcTlsPort, *partnerUser, *partnerPassword, *device, *inkey, *outkey, *caBundle;
 	char keys[BAR_KS_COUNT];
+	int sampleRate;
 	BarMsgFormatStr_t msgFormat[MSG_COUNT];
 } BarSettings_t;