output/jack: dynamic source port list

Same as the previous patch: create up to 16 configured source ports.
The plugin tries to do its best at guessing the right combination for
the given input file, the number of source and destination ports.

3 files changed, 87 insertions, 38 deletions

diff --git a/NEWS b/NEWS
index b181a9a8..a920d501 100644
--- a/NEWS
+++ b/NEWS
@@ -39,7 +39,7 @@ ver 0.16 (20??/??/??)
   - jack: added option "client_name"
   - jack: clear ring buffers before activating
   - jack: renamed option "ports" to "destination_ports"
-  - jack: support mono input
+  - jack: support more than two audio channels
   - httpd: bind port when output is enabled
   - wildcards allowed in audio_format configuration
   - consistently lock audio output objects
diff --git a/doc/user.xml b/doc/user.xml
index 6eba599e..aabbd33f 100644
--- a/doc/user.xml
+++ b/doc/user.xml
@@ -758,6 +758,18 @@ cd mpd-version</programlisting>
               </row>
               <row>
                 <entry>
+                  <varname>source_ports</varname>
+                  <parameter>A,B</parameter>
+                </entry>
+                <entry>
+                  The names of the JACK source ports to be created.
+                  By default, the ports "left" and "right" are
+                  created.  To use more ports, you have to tweak this
+                  option.
+                </entry>
+              </row>
+              <row>
+                <entry>
                   <varname>destination_ports</varname>
                   <parameter>A,B</parameter>
                 </entry>
diff --git a/src/output/jack_output_plugin.c b/src/output/jack_output_plugin.c
index 14493715..d2f7747d 100644
--- a/src/output/jack_output_plugin.c
+++ b/src/output/jack_output_plugin.c
@@ -42,10 +42,6 @@ enum {
 
 static const size_t sample_size = sizeof(jack_default_audio_sample_t);
 
-static const char *const port_names[2] = {
-	"left", "right",
-};
-
 struct jack_data {
 	/**
 	 * libjack options passed to jack_client_open().
@@ -56,6 +52,9 @@ struct jack_data {
 
 	/* configuration */
 
+	char *source_ports[MAX_PORTS];
+	unsigned num_source_ports;
+
 	char *destination_ports[MAX_PORTS];
 	unsigned num_destination_ports;
 
@@ -65,9 +64,9 @@ struct jack_data {
 	struct audio_format audio_format;
 
 	/* jack library stuff */
-	jack_port_t *ports[2];
+	jack_port_t *ports[MAX_PORTS];
 	jack_client_t *client;
-	jack_ringbuffer_t *ringbuffer[2];
+	jack_ringbuffer_t *ringbuffer[MAX_PORTS];
 
 	bool shutdown;
 
@@ -126,6 +125,16 @@ mpd_jack_process(jack_nframes_t nframes, void *arg)
 			out[available++] = 0.0;
 	}
 
+	/* generate silence for the unused source ports */
+
+	for (unsigned i = jd->audio_format.channels;
+	     i < jd->num_source_ports; ++i) {
+		out = jack_port_get_buffer(jd->ports[i], nframes);
+
+		for (jack_nframes_t f = 0; f < nframes; ++f)
+			out[f] = 0.0;
+	}
+
 	return 0;
 }
 
@@ -141,7 +150,9 @@ set_audioformat(struct jack_data *jd, struct audio_format *audio_format)
 {
 	audio_format->sample_rate = jack_get_sample_rate(jd->client);
 
-	if (audio_format->channels > 2)
+	if (jd->num_source_ports == 1)
+		audio_format->channels = 1;
+	else if (audio_format->channels > jd->num_source_ports)
 		audio_format->channels = 2;
 
 	if (audio_format->bits != 16 && audio_format->bits != 24)
@@ -200,14 +211,15 @@ mpd_jack_connect(struct jack_data *jd, GError **error_r)
 	jack_set_process_callback(jd->client, mpd_jack_process, jd);
 	jack_on_shutdown(jd->client, mpd_jack_shutdown, jd);
 
-	for (unsigned i = 0; i < G_N_ELEMENTS(jd->ports); ++i) {
-		jd->ports[i] = jack_port_register(jd->client, port_names[i],
+	for (unsigned i = 0; i < jd->num_source_ports; ++i) {
+		jd->ports[i] = jack_port_register(jd->client,
+						  jd->source_ports[i],
 						  JACK_DEFAULT_AUDIO_TYPE,
 						  JackPortIsOutput, 0);
 		if (jd->ports[i] == NULL) {
 			g_set_error(error_r, jack_output_quark(), 0,
 				    "Cannot register output port \"%s\"",
-				    port_names[i]);
+				    jd->source_ports[i]);
 			mpd_jack_disconnect(jd);
 			return false;
 		}
@@ -272,6 +284,16 @@ mpd_jack_init(G_GNUC_UNUSED const struct audio_format *audio_format,
 	if (!config_get_block_bool(param, "autostart", false))
 		jd->options |= JackNoStartServer;
 
+	/* configure the source ports */
+
+	value = config_get_block_string(param, "source_ports", "left,right");
+	jd->num_source_ports = parse_port_list(param->line, value,
+					       jd->source_ports, error_r);
+	if (jd->num_source_ports == 0)
+		return NULL;
+
+	/* configure the destination ports */
+
 	value = config_get_block_string(param, "destination_ports", NULL);
 	if (value == NULL) {
 		/* compatibility with MPD < 0.16 */
@@ -291,6 +313,13 @@ mpd_jack_init(G_GNUC_UNUSED const struct audio_format *audio_format,
 		jd->num_destination_ports = 0;
 	}
 
+	if (jd->num_destination_ports > 0 &&
+	    jd->num_destination_ports != jd->num_source_ports)
+		g_warning("number of source ports (%u) mismatches the "
+			  "number of destination ports (%u) in line %d",
+			  jd->num_source_ports, jd->num_destination_ports,
+			  param->line);
+
 	jd->ringbuffer_size =
 		config_get_block_unsigned(param, "ringbuffer_size", 32768);
 
@@ -319,7 +348,7 @@ mpd_jack_enable(void *data, GError **error_r)
 {
 	struct jack_data *jd = (struct jack_data *)data;
 
-	for (unsigned i = 0; i < G_N_ELEMENTS(jd->ringbuffer); ++i)
+	for (unsigned i = 0; i < jd->num_source_ports; ++i)
 		jd->ringbuffer[i] = NULL;
 
 	return mpd_jack_connect(jd, error_r);
@@ -333,7 +362,7 @@ mpd_jack_disable(void *data)
 	if (jd->client != NULL)
 		mpd_jack_disconnect(jd);
 
-	for (unsigned i = 0; i < G_N_ELEMENTS(jd->ringbuffer); ++i) {
+	for (unsigned i = 0; i < jd->num_source_ports; ++i) {
 		if (jd->ringbuffer[i] != NULL) {
 			jack_ringbuffer_free(jd->ringbuffer[i]);
 			jd->ringbuffer[i] = NULL;
@@ -364,15 +393,17 @@ static bool
 mpd_jack_start(struct jack_data *jd, GError **error_r)
 {
 	const char *destination_ports[MAX_PORTS], **jports;
+	const char *duplicate_port = NULL;
 	unsigned num_destination_ports;
 
 	assert(jd->client != NULL);
+	assert(jd->audio_format.channels <= jd->num_source_ports);
 
 	/* allocate the ring buffers on the first open(); these
 	   persist until MPD exits.  It's too unsafe to delete them
 	   because we can never know when mpd_jack_process() gets
 	   called */
-	for (unsigned i = 0; i < G_N_ELEMENTS(jd->ringbuffer); ++i) {
+	for (unsigned i = 0; i < jd->num_source_ports; ++i) {
 		if (jd->ringbuffer[i] == NULL)
 			jd->ringbuffer[i] =
 				jack_ringbuffer_create(jd->ringbuffer_size);
@@ -425,16 +456,26 @@ mpd_jack_start(struct jack_data *jd, GError **error_r)
 
 	assert(num_destination_ports > 0);
 
-	if (jd->audio_format.channels == 2 && num_destination_ports == 1) {
+	if (jd->audio_format.channels >= 2 && num_destination_ports == 1) {
 		/* mix stereo signal on one speaker */
 
-		destination_ports[1] = destination_ports[0];
-		num_destination_ports = 2;
+		while (num_destination_ports < jd->audio_format.channels)
+			destination_ports[num_destination_ports++] =
+				destination_ports[0];
+	} else if (num_destination_ports > jd->audio_format.channels) {
+		if (jd->audio_format.channels == 1 && num_destination_ports > 2) {
+			/* mono input file: connect the one source
+			   channel to the both destination channels */
+			duplicate_port = destination_ports[1];
+			num_destination_ports = 1;
+		} else
+			/* connect only as many ports as we need */
+			num_destination_ports = jd->audio_format.channels;
 	}
 
-	assert(jd->audio_format.channels <= num_destination_ports);
+	assert(num_destination_ports <= jd->num_source_ports);
 
-	for (unsigned i = 0; i < jd->audio_format.channels; ++i) {
+	for (unsigned i = 0; i < num_destination_ports; ++i) {
 		int ret;
 
 		ret = jack_connect(jd->client, jack_port_name(jd->ports[i]),
@@ -452,17 +493,17 @@ mpd_jack_start(struct jack_data *jd, GError **error_r)
 		}
 	}
 
-	if (jd->audio_format.channels == 1 && num_destination_ports == 2) {
+	if (duplicate_port != NULL) {
 		/* mono input file: connect the one source channel to
 		   the both destination channels */
 		int ret;
 
 		ret = jack_connect(jd->client, jack_port_name(jd->ports[0]),
-				   destination_ports[1]);
+				   duplicate_port);
 		if (ret != 0) {
 			g_set_error(error_r, jack_output_quark(), 0,
 				    "Not a valid JACK port: %s",
-				    destination_ports[1]);
+				    duplicate_port);
 
 			if (jports != NULL)
 				free(jports);
@@ -518,15 +559,12 @@ mpd_jack_write_samples_16(struct jack_data *jd, const int16_t *src,
 			  unsigned num_samples)
 {
 	jack_default_audio_sample_t sample;
+	unsigned i;
 
 	while (num_samples-- > 0) {
-		sample = sample_16_to_jack(*src++);
-		jack_ringbuffer_write(jd->ringbuffer[0], (void*)&sample,
-				      sizeof(sample));
-
-		if (jd->audio_format.channels >= 2) {
+		for (i = 0; i < jd->audio_format.channels; ++i) {
 			sample = sample_16_to_jack(*src++);
-			jack_ringbuffer_write(jd->ringbuffer[1], (void*)&sample,
+			jack_ringbuffer_write(jd->ringbuffer[i], (void*)&sample,
 					      sizeof(sample));
 		}
 	}
@@ -543,15 +581,12 @@ mpd_jack_write_samples_24(struct jack_data *jd, const int32_t *src,
 			  unsigned num_samples)
 {
 	jack_default_audio_sample_t sample;
+	unsigned i;
 
 	while (num_samples-- > 0) {
-		sample = sample_24_to_jack(*src++);
-		jack_ringbuffer_write(jd->ringbuffer[0], (void*)&sample,
-				      sizeof(sample));
-
-		if (jd->audio_format.channels >= 2) {
+		for (i = 0; i < jd->audio_format.channels; ++i) {
 			sample = sample_24_to_jack(*src++);
-			jack_ringbuffer_write(jd->ringbuffer[1], (void*)&sample,
+			jack_ringbuffer_write(jd->ringbuffer[i], (void*)&sample,
 					      sizeof(sample));
 		}
 	}
@@ -598,10 +633,12 @@ mpd_jack_play(void *data, const void *chunk, size_t size, GError **error_r)
 		}
 
 		space = jack_ringbuffer_write_space(jd->ringbuffer[0]);
-		space1 = jack_ringbuffer_write_space(jd->ringbuffer[1]);
-		if (space > space1)
-			/* send data symmetrically */
-			space = space1;
+		for (unsigned i = 1; i < jd->audio_format.channels; ++i) {
+			space1 = jack_ringbuffer_write_space(jd->ringbuffer[i]);
+			if (space > space1)
+				/* send data symmetrically */
+				space = space1;
+		}
 
 		if (space >= frame_size)
 			break;