Working multi-channel pads for LV2 plugins.

5 files changed, 322 insertions, 130 deletions

diff --git a/ext/ladspa/gstladspa.c b/ext/ladspa/gstladspa.c
index b62d4c993..e3fc64cbe 100644
--- a/ext/ladspa/gstladspa.c
+++ b/ext/ladspa/gstladspa.c
@@ -125,10 +125,10 @@ gst_ladspa_base_init (gpointer g_class)
 
       if (LADSPA_IS_PORT_INPUT (p))
         gst_signal_processor_class_add_pad_template (gsp_class, name,
-            GST_PAD_SINK, gsp_class->num_audio_in++);
+            GST_PAD_SINK, gsp_class->num_audio_in++, 1);
       else
         gst_signal_processor_class_add_pad_template (gsp_class, name,
-            GST_PAD_SRC, gsp_class->num_audio_out++);
+            GST_PAD_SRC, gsp_class->num_audio_out++, 1);
 
       g_free (name);
     } else if (LADSPA_IS_PORT_CONTROL (p)) {
diff --git a/ext/lv2/gstlv2.c b/ext/lv2/gstlv2.c
index eff0a41bb..fdd0292b3 100644
--- a/ext/lv2/gstlv2.c
+++ b/ext/lv2/gstlv2.c
@@ -54,6 +54,7 @@ SLV2Value integer_prop;
 SLV2Value toggled_prop;
 SLV2Value in_place_broken_pred;
 SLV2Value in_group_pred;
+SLV2Value lv2_symbol_pred;
 
 static GstSignalProcessorClass *parent_class;
 
@@ -62,12 +63,15 @@ static GstPlugin *gst_lv2_plugin;
 GST_DEBUG_CATEGORY_STATIC (lv2_debug);
 #define GST_CAT_DEFAULT lv2_debug
 
-static gint
-gst_lv2_value_cmp (gconstpointer a, gconstpointer b)
+/** Find and return the group @a uri in @a groups, or NULL if not found */
+static GstLV2Group *
+gst_lv2_class_find_group (GArray * groups, SLV2Value uri)
 {
-  if (slv2_value_equals ((SLV2Value) a, (SLV2Value) b))
-    return 0;
-  return 1;
+  int i = 0;
+  for (; i < groups->len; ++i)
+    if (slv2_value_equals (g_array_index (groups, GstLV2Group, i).uri, uri))
+      return &g_array_index (groups, GstLV2Group, i);
+  return NULL;
 }
 
 static void
@@ -79,8 +83,9 @@ gst_lv2_base_init (gpointer g_class)
   GstElementDetails *details;
   SLV2Plugin lv2plugin;
   SLV2Value val;
-  SLV2Values values;
-  guint j, audio_in_count, audio_out_count, control_in_count, control_out_count;
+  SLV2Values values, sub_values;
+  GstLV2Group *group = NULL;
+  guint j, in_pad_index = 0, out_pad_index = 0;
   gchar *klass_tags;
 
   GST_DEBUG ("base_init %p", g_class);
@@ -90,89 +95,116 @@ gst_lv2_base_init (gpointer g_class)
 
   g_assert (lv2plugin);
 
-  /* audio ports (pads) */
-  gsp_class->num_audio_in = slv2_plugin_get_num_ports_of_class (lv2plugin,
-      audio_class, input_class, NULL);
-  gsp_class->num_audio_out = slv2_plugin_get_num_ports_of_class (lv2plugin,
-      audio_class, output_class, NULL);
-
-  /* control ports (properties) */
-  gsp_class->num_control_in = slv2_plugin_get_num_ports_of_class (lv2plugin,
-      control_class, input_class, NULL);
-  gsp_class->num_control_out = slv2_plugin_get_num_ports_of_class (lv2plugin,
-      control_class, output_class, NULL);
-
-  klass->audio_in_ports = g_new0 (struct _GstLV2Port, gsp_class->num_audio_in);
-  klass->audio_out_ports =
-      g_new0 (struct _GstLV2Port, gsp_class->num_audio_out);
-  klass->control_in_ports =
-      g_new0 (struct _GstLV2Port, gsp_class->num_control_in);
-  klass->control_out_ports =
-      g_new0 (struct _GstLV2Port, gsp_class->num_control_out);
-
-  klass->groups = NULL;
-
-  /* find port groups */
-  audio_in_count = audio_out_count = control_in_count = control_out_count = 0;
+  gsp_class->num_group_in = 0;
+  gsp_class->num_group_out = 0;
+  gsp_class->num_audio_in = 0;
+  gsp_class->num_audio_out = 0;
+  gsp_class->num_control_in = 0;
+  gsp_class->num_control_out = 0;
+
+  klass->in_groups = g_array_new (FALSE, TRUE, sizeof (GstLV2Group));
+  klass->out_groups = g_array_new (FALSE, TRUE, sizeof (GstLV2Group));
+  klass->audio_in_ports = g_array_new (FALSE, TRUE, sizeof (GstLV2Port));
+  klass->audio_out_ports = g_array_new (FALSE, TRUE, sizeof (GstLV2Port));
+  klass->control_in_ports = g_array_new (FALSE, TRUE, sizeof (GstLV2Port));
+  klass->control_out_ports = g_array_new (FALSE, TRUE, sizeof (GstLV2Port));
+
+  /* find ports and groups */
   for (j = 0; j < slv2_plugin_get_num_ports (lv2plugin); j++) {
-    SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, j);
-    gboolean is_input = slv2_port_is_a (lv2plugin, port, input_class);
-    struct _GstLV2Port *desc = NULL;
-    if (slv2_port_is_a (lv2plugin, port, audio_class)) {
-      if (is_input)
-        desc = &klass->audio_in_ports[audio_in_count++];
-      else
-        desc = &klass->audio_out_ports[audio_out_count++];
-    } else if (slv2_port_is_a (lv2plugin, port, control_class)) {
-      if (is_input)
-        desc = &klass->control_in_ports[control_in_count++];
-      else
-        desc = &klass->control_out_ports[control_out_count++];
-    } else {
-      /* unknown port type */
-      continue;
-    }
-    desc->index = j;
+    const SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, j);
+    const gboolean is_input = slv2_port_is_a (lv2plugin, port, input_class);
+    struct _GstLV2Port desc = { j, 0 };
     values = slv2_port_get_value (lv2plugin, port, in_group_pred);
+
     if (slv2_values_size (values) > 0) {
-      SLV2Value v = slv2_values_get_at (values, 0);
-      desc->group = v;
-      if (!g_slist_find_custom (klass->groups, v, gst_lv2_value_cmp)) {
-        klass->groups =
-            g_slist_prepend (klass->groups, slv2_value_duplicate (v));
+      /* port is part of a group */
+      SLV2Value group_uri = slv2_values_get_at (values, 0);
+      GArray *groups = is_input ? klass->in_groups : klass->out_groups;
+      GstLV2Group *group = gst_lv2_class_find_group (groups, group_uri);
+      if (group == NULL) {
+        GstLV2Group g;
+        g.uri = slv2_value_duplicate (group_uri);
+        g.pad = is_input ? in_pad_index++ : out_pad_index++;
+        g.ports = g_array_new (FALSE, TRUE, sizeof (GstLV2Port));
+        sub_values = slv2_plugin_get_value_for_subject (lv2plugin, group_uri,
+            lv2_symbol_pred);
+        if (slv2_values_size (sub_values) > 0)
+          g.symbol = slv2_value_duplicate (slv2_values_get_at (sub_values, 0));
+        else
+          g.symbol = NULL;
+        slv2_values_free (sub_values);
+
+        g_array_append_val (groups, g);
+        group = &g_array_index (groups, GstLV2Group, groups->len - 1);
+      }
+
+      g_array_append_val (group->ports, desc);
+
+    } else {
+      /* port is not part of a group */
+      if (slv2_port_is_a (lv2plugin, port, audio_class)) {
+        desc.pad = is_input ? in_pad_index++ : out_pad_index++;
+        if (is_input)
+          g_array_append_val (klass->audio_in_ports, desc);
+        else
+          g_array_append_val (klass->audio_out_ports, desc);
+      } else if (slv2_port_is_a (lv2plugin, port, control_class)) {
+        if (is_input)
+          g_array_append_val (klass->control_in_ports, desc);
+        else
+          g_array_append_val (klass->control_out_ports, desc);
+      } else {
+        /* unknown port type */
+        continue;
       }
-      g_assert (g_slist_find_custom (klass->groups, v, gst_lv2_value_cmp));
     }
     slv2_values_free (values);
   }
-  g_assert (audio_in_count == gsp_class->num_audio_in);
-  g_assert (audio_out_count == gsp_class->num_audio_out);
-  g_assert (control_in_count == gsp_class->num_control_in);
-  g_assert (control_out_count == gsp_class->num_control_out);
 
-  /* add pad templates */
-  audio_in_count = audio_out_count = 0;
-  for (j = 0; j < slv2_plugin_get_num_ports (lv2plugin); j++) {
-    SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, j);
-    if (slv2_port_is_a (lv2plugin, port, audio_class)) {
-      gchar *name =
-          g_strdup (slv2_value_as_string (slv2_port_get_symbol (lv2plugin,
-                  port)));
-
-      GST_DEBUG ("LV2 port name: \"%s\"", name);
-
-      if (slv2_port_is_a (lv2plugin, port, input_class))
-        gst_signal_processor_class_add_pad_template (gsp_class, name,
-            GST_PAD_SINK, audio_in_count++);
-      else if (slv2_port_is_a (lv2plugin, port, output_class))
-        gst_signal_processor_class_add_pad_template (gsp_class, name,
-            GST_PAD_SRC, audio_out_count++);
-
-      g_free (name);
-    }
+  gsp_class->num_group_in = klass->in_groups->len;
+  gsp_class->num_group_out = klass->out_groups->len;
+  gsp_class->num_audio_in = klass->audio_in_ports->len;
+  gsp_class->num_audio_out = klass->audio_out_ports->len;
+  gsp_class->num_control_in = klass->control_in_ports->len;
+  gsp_class->num_control_out = klass->control_out_ports->len;
+
+  /* add input group pad templates */
+  for (j = 0; j < gsp_class->num_group_in; ++j) {
+    group = &g_array_index (klass->in_groups, GstLV2Group, j);
+    gst_signal_processor_class_add_pad_template (gsp_class,
+        slv2_value_as_string (group->symbol),
+        GST_PAD_SINK, j, group->ports->len);
+  }
+
+  /* add output group pad templates */
+  for (j = 0; j < gsp_class->num_group_out; ++j) {
+    group = &g_array_index (klass->out_groups, GstLV2Group, j);
+    gst_signal_processor_class_add_pad_template (gsp_class,
+        slv2_value_as_string (group->symbol),
+        GST_PAD_SRC, j, group->ports->len);
+  }
+
+  /* add non-grouped input port pad templates */
+  for (j = 0; j < gsp_class->num_audio_in; ++j) {
+    struct _GstLV2Port *desc =
+        &g_array_index (klass->audio_in_ports, GstLV2Port, j);
+    SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, desc->index);
+    const gchar *name =
+        slv2_value_as_string (slv2_port_get_symbol (lv2plugin, port));
+    gst_signal_processor_class_add_pad_template (gsp_class, name, GST_PAD_SINK,
+        j, 1);
+  }
+
+  /* add non-grouped output port pad templates */
+  for (j = 0; j < gsp_class->num_audio_out; ++j) {
+    struct _GstLV2Port *desc =
+        &g_array_index (klass->audio_out_ports, GstLV2Port, j);
+    SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, desc->index);
+    const gchar *name =
+        slv2_value_as_string (slv2_port_get_symbol (lv2plugin, port));
+    gst_signal_processor_class_add_pad_template (gsp_class, name, GST_PAD_SINK,
+        j, 1);
   }
-  g_assert (audio_in_count == gsp_class->num_audio_in);
-  g_assert (audio_out_count == gsp_class->num_audio_out);
 
   /* construct the element details struct */
   details = g_new0 (GstElementDetails, 1);
@@ -257,6 +289,10 @@ gst_lv2_class_get_param_spec (GstLV2Class * klass, gint portnum)
   if (lv2max)
     upper = slv2_value_as_float (lv2max);
 
+  slv2_value_free (lv2def);
+  slv2_value_free (lv2min);
+  slv2_value_free (lv2max);
+
   if (def < lower) {
     GST_WARNING ("%s has lower bound %f > default %f\n",
         slv2_value_as_string (slv2_plugin_get_uri (lv2plugin)), lower, def);
@@ -306,7 +342,8 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
   for (i = 0; i < gsp_class->num_control_in; i++) {
     GParamSpec *p;
 
-    p = gst_lv2_class_get_param_spec (klass, klass->control_in_ports[i].index);
+    p = gst_lv2_class_get_param_spec (klass,
+        g_array_index (klass->control_in_ports, GstLV2Port, i).index);
 
     /* properties have an offset of 1 */
     g_object_class_install_property (G_OBJECT_CLASS (klass), i + 1, p);
@@ -315,7 +352,8 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
   for (i = 0; i < gsp_class->num_control_out; i++) {
     GParamSpec *p;
 
-    p = gst_lv2_class_get_param_spec (klass, klass->control_out_ports[i].index);
+    p = gst_lv2_class_get_param_spec (klass,
+        g_array_index (klass->control_out_ports, GstLV2Port, i).index);
 
     /* properties have an offset of 1, and we already added num_control_in */
     g_object_class_install_property (G_OBJECT_CLASS (klass),
@@ -425,10 +463,12 @@ gst_lv2_setup (GstSignalProcessor * gsp, guint sample_rate)
   /* connect the control ports */
   for (i = 0; i < gsp_class->num_control_in; i++)
     slv2_instance_connect_port (lv2->instance,
-        oclass->control_in_ports[i].index, &(gsp->control_in[i]));
+        g_array_index (oclass->control_in_ports, GstLV2Port, i).index,
+        &(gsp->control_in[i]));
   for (i = 0; i < gsp_class->num_control_out; i++)
     slv2_instance_connect_port (lv2->instance,
-        oclass->control_out_ports[i].index, &(gsp->control_out[i]));
+        g_array_index (oclass->control_out_ports, GstLV2Port, i).index,
+        &(gsp->control_out[i]));
 
   return TRUE;
 }
@@ -486,18 +526,43 @@ gst_lv2_process (GstSignalProcessor * gsp, guint nframes)
   GstSignalProcessorClass *gsp_class;
   GstLV2 *lv2;
   GstLV2Class *oclass;
-  guint i;
+  GstLV2Group *lv2_group;
+  GstLV2Port *lv2_port;
+  GstSignalProcessorGroup *gst_group;
+  guint i, j;
 
   gsp_class = GST_SIGNAL_PROCESSOR_GET_CLASS (gsp);
   lv2 = (GstLV2 *) gsp;
   oclass = (GstLV2Class *) gsp_class;
 
-  for (i = 0; i < gsp_class->num_audio_in; i++)
-    slv2_instance_connect_port (lv2->instance,
-        oclass->audio_in_ports[i].index, gsp->audio_in[i]);
-  for (i = 0; i < gsp_class->num_audio_out; i++)
-    slv2_instance_connect_port (lv2->instance,
-        oclass->audio_out_ports[i].index, gsp->audio_out[i]);
+  for (i = 0; i < gsp_class->num_group_in; i++) {
+    lv2_group = &g_array_index (oclass->in_groups, GstLV2Group, i);
+    gst_group = &gsp->group_in[i];
+    for (j = 0; j < lv2_group->ports->len; ++j) {
+      lv2_port = &g_array_index (lv2_group->ports, GstLV2Port, j);
+      slv2_instance_connect_port (lv2->instance, lv2_port->index,
+          gst_group->buffer + (j * nframes));
+    }
+  }
+  for (i = 0; i < gsp_class->num_audio_in; i++) {
+    lv2_port = &g_array_index (oclass->audio_in_ports, GstLV2Port, i);
+    slv2_instance_connect_port (lv2->instance, lv2_port->index,
+        gsp->audio_in[i]);
+  }
+  for (i = 0; i < gsp_class->num_group_out; i++) {
+    lv2_group = &g_array_index (oclass->out_groups, GstLV2Group, i);
+    gst_group = &gsp->group_out[i];
+    for (j = 0; j < lv2_group->ports->len; ++j) {
+      lv2_port = &g_array_index (lv2_group->ports, GstLV2Port, j);
+      slv2_instance_connect_port (lv2->instance, lv2_port->index,
+          gst_group->buffer + (j * nframes));
+    }
+  }
+  for (i = 0; i < gsp_class->num_audio_out; i++) {
+    lv2_port = &g_array_index (oclass->audio_out_ports, GstLV2Port, i);
+    slv2_instance_connect_port (lv2->instance, lv2_port->index,
+        gsp->audio_out[i]);
+  }
 
   slv2_instance_run (lv2->instance, nframes);
 }
@@ -565,15 +630,15 @@ plugin_init (GstPlugin * plugin)
   control_class = slv2_value_new_uri (world, SLV2_PORT_CLASS_CONTROL);
   input_class = slv2_value_new_uri (world, SLV2_PORT_CLASS_INPUT);
   output_class = slv2_value_new_uri (world, SLV2_PORT_CLASS_OUTPUT);
-  integer_prop =
-      slv2_value_new_uri (world, "http://lv2plug.in/ns/lv2core#integer");
-  toggled_prop =
-      slv2_value_new_uri (world, "http://lv2plug.in/ns/lv2core#toggled");
-  in_place_broken_pred = slv2_value_new_uri (world,
-      "http://lv2plug.in/ns/lv2core#inPlaceBroken");
-  in_group_pred =
-      slv2_value_new_uri (world,
-      "http://lv2plug.in/ns/dev/port-groups#inGroup");
+
+#define NS_LV2 "http://lv2plug.in/ns/lv2core#"
+#define NS_PG  "http://lv2plug.in/ns/dev/port-groups#"
+
+  integer_prop = slv2_value_new_uri (world, NS_LV2 "integer");
+  toggled_prop = slv2_value_new_uri (world, NS_LV2 "toggled");
+  in_place_broken_pred = slv2_value_new_uri (world, NS_LV2 "inPlaceBroken");
+  in_group_pred = slv2_value_new_uri (world, NS_PG "inGroup");
+  lv2_symbol_pred = slv2_value_new_string (world, NS_LV2 "symbol");
 
   parent_class = g_type_class_ref (GST_TYPE_SIGNAL_PROCESSOR);
 
diff --git a/ext/lv2/gstlv2.h b/ext/lv2/gstlv2.h
index 836f1a0bb..fb384cce2 100644
--- a/ext/lv2/gstlv2.h
+++ b/ext/lv2/gstlv2.h
@@ -46,6 +46,8 @@ typedef struct _lv2_control_info {
 
 typedef struct _GstLV2 GstLV2;
 typedef struct _GstLV2Class GstLV2Class;
+typedef struct _GstLV2Group GstLV2Group;
+typedef struct _GstLV2Port GstLV2Port;
 
 
 struct _GstLV2 {
@@ -57,9 +59,16 @@ struct _GstLV2 {
   gboolean activated;
 };
 
+struct _GstLV2Group {
+  SLV2Value uri; /**< RDF resource (URI or blank node) */
+  guint pad; /**< Gst pad index */
+  SLV2Value symbol; /**< Gst pad name / LV2 group symbol */
+  GArray *ports; /**< Array of GstLV2Port */
+};
+
 struct _GstLV2Port {
-  gint      index;
-  SLV2Value group;
+  gint index; /**< LV2 port index (on LV2 plugin) */
+  gint pad; /**< Gst pad index (iff not part of a group) */
 };
 
 struct _GstLV2Class {
@@ -67,12 +76,13 @@ struct _GstLV2Class {
 
   SLV2Plugin plugin;
 
-  GSList *groups;
+  GArray *in_groups; /**< Array of GstLV2Group */
+  GArray *out_groups; /**< Array of GstLV2Group */
+  GArray *audio_in_ports; /**< Array of GstLV2Port */
+  GArray *audio_out_ports; /**< Array of GstLV2Port */
+  GArray *control_in_ports; /**< Array of GstLV2Port */
+  GArray *control_out_ports; /**< Array of GstLV2Port */
 
-  struct _GstLV2Port *audio_in_ports;
-  struct _GstLV2Port *audio_out_ports;
-  struct _GstLV2Port *control_in_ports;
-  struct _GstLV2Port *control_out_ports;
 };
 
 
diff --git a/gst-libs/gst/signalprocessor/gstsignalprocessor.c b/gst-libs/gst/signalprocessor/gstsignalprocessor.c
index e794ddfa1..e502941ee 100644
--- a/gst-libs/gst/signalprocessor/gstsignalprocessor.c
+++ b/gst-libs/gst/signalprocessor/gstsignalprocessor.c
@@ -31,13 +31,14 @@
  * 1. store each received buffer on the pad and decrement pending_in
  * 2. when pending_in==0, process as much as we can and push outputs
  *
- * In pull mode (gst_signal_processor_getrange) is operates as follows:
+ * In pull mode (gst_signal_processor_getrange) it operates as follows:
  * 1. if there is an output ready, deliver
  * 2. otherwise pull from each sink-pad, process requested frames and deliver
  *    the buffer
  */
 
 #include <stdlib.h>
+#include <string.h>
 
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
@@ -63,6 +64,7 @@ struct _GstSignalProcessorPadTemplate
   GstPadTemplate parent;
 
   guint index;
+  guint channels;
 };
 
 static GType
@@ -92,11 +94,10 @@ gst_signal_processor_pad_template_get_type (void)
  */
 void
 gst_signal_processor_class_add_pad_template (GstSignalProcessorClass * klass,
-    const gchar * name, GstPadDirection direction, guint index)
+    const gchar * name, GstPadDirection direction, guint index, guint channels)
 {
   GstPadTemplate *new;
   GstCaps *caps;
-  guint channels = 1;
 
   g_return_if_fail (GST_IS_SIGNAL_PROCESSOR_CLASS (klass));
   g_return_if_fail (name != NULL);
@@ -111,6 +112,7 @@ gst_signal_processor_class_add_pad_template (GstSignalProcessorClass * klass,
       "direction", direction, "presence", GST_PAD_ALWAYS, "caps", caps, NULL);
 
   GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (new)->index = index;
+  GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (new)->channels = channels;
 
   gst_element_class_add_pad_template (GST_ELEMENT_CLASS (klass), new);
 }
@@ -132,6 +134,9 @@ struct _GstSignalProcessorPad
   /* index for the pad per direction (starting from 0) */
   guint index;
 
+  /* number of channels for the pad */
+  guint channels;
+
   /* these are only used for sink pads */
   guint samples_avail;          /* available mono sample frames */
   gfloat *data;                 /* data pointer to read from / write to */
@@ -208,6 +213,8 @@ gst_signal_processor_add_pad_from_template (GstSignalProcessor * self,
       "template", templ, NULL);
   GST_SIGNAL_PROCESSOR_PAD (new)->index =
       GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (templ)->index;
+  GST_SIGNAL_PROCESSOR_PAD (new)->channels =
+      GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (templ)->channels;
 
   gst_pad_set_setcaps_function (new,
       GST_DEBUG_FUNCPTR (gst_signal_processor_setcaps));
@@ -244,20 +251,21 @@ gst_signal_processor_init (GstSignalProcessor * self,
 
   while (templates) {
     GstPadTemplate *templ = GST_PAD_TEMPLATE (templates->data);
-
     gst_signal_processor_add_pad_from_template (self, templ);
     templates = templates->next;
   }
 
   self->state = GST_SIGNAL_PROCESSOR_STATE_NULL;
 
+  self->group_in = g_new0 (GstSignalProcessorGroup, klass->num_group_in);
+  self->group_out = g_new0 (GstSignalProcessorGroup, klass->num_group_out);
   self->audio_in = g_new0 (gfloat *, klass->num_audio_in);
-  self->control_in = g_new0 (gfloat, klass->num_control_in);
   self->audio_out = g_new0 (gfloat *, klass->num_audio_out);
+  self->control_in = g_new0 (gfloat, klass->num_control_in);
   self->control_out = g_new0 (gfloat, klass->num_control_out);
 
   /* init */
-  self->pending_in = klass->num_audio_in;
+  self->pending_in = klass->num_group_in + klass->num_audio_in;
   self->pending_out = 0;
 
   self->sample_rate = 0;
@@ -268,12 +276,16 @@ gst_signal_processor_finalize (GObject * object)
 {
   GstSignalProcessor *self = GST_SIGNAL_PROCESSOR (object);
 
+  g_free (self->group_in);
+  self->group_in = NULL;
+  g_free (self->group_out);
+  self->group_out = NULL;
   g_free (self->audio_in);
   self->audio_in = NULL;
-  g_free (self->control_in);
-  self->control_in = NULL;
   g_free (self->audio_out);
   self->audio_out = NULL;
+  g_free (self->control_in);
+  self->control_in = NULL;
   g_free (self->control_out);
   self->control_out = NULL;
 
@@ -369,6 +381,7 @@ static void
 gst_signal_processor_cleanup (GstSignalProcessor * self)
 {
   GstSignalProcessorClass *klass;
+  gint i;
 
   klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
 
@@ -379,6 +392,16 @@ gst_signal_processor_cleanup (GstSignalProcessor * self)
   if (klass->cleanup)
     klass->cleanup (self);
 
+  for (i = 0; i < klass->num_group_in; ++i) {
+    g_free (self->group_in[i].buffer);
+    memset (&self->group_in[i], '\0', sizeof (GstSignalProcessorGroup));
+  }
+
+  for (i = 0; i < klass->num_group_out; ++i) {
+    g_free (self->group_out[i].buffer);
+    memset (&self->group_in[i], '\0', sizeof (GstSignalProcessorGroup));
+  }
+
   self->state = GST_SIGNAL_PROCESSOR_STATE_NULL;
 }
 
@@ -503,6 +526,36 @@ impossible:
   }
 }
 
+/** De-interleave a pad (gstreamer => plugin) */
+static void
+gst_signal_processor_deinterleave_group (GstSignalProcessorGroup * group,
+    guint nframes)
+{
+  guint i, j;
+  g_assert (group->nframes == nframes);
+  g_assert (group->interleaved_buffer);
+  g_assert (group->buffer);
+  for (i = 0; i < nframes; ++i)
+    for (j = 0; j < group->channels; ++j)
+      group->buffer[(j * nframes) + i]
+          = group->interleaved_buffer[(i * group->channels) + j];
+}
+
+/** Interleave a pad (plugin => gstreamer) */
+static void
+gst_signal_processor_interleave_group (GstSignalProcessorGroup * group,
+    guint nframes)
+{
+  guint i, j;
+  g_assert (group->nframes == nframes);
+  g_assert (group->interleaved_buffer);
+  g_assert (group->buffer);
+  for (i = 0; i < nframes; ++i)
+    for (j = 0; j < group->channels; ++j)
+      group->interleaved_buffer[(i * group->channels) + j]
+          = group->buffer[(j * nframes) + i];
+}
+
 static gboolean
 gst_signal_processor_event (GstPad * pad, GstEvent * event)
 {
@@ -543,18 +596,38 @@ gst_signal_processor_prepare (GstSignalProcessor * self, guint nframes)
   GstSignalProcessorClass *klass;
   GList *sinks, *srcs;
   guint samples_avail = nframes;
+  guint i, in_group_index = 0, out_group_index = 0;
 
   klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
 
   /* first, assign audio_in pointers, and determine the number of samples that
    * we can process */
-  for (sinks = elem->sinkpads; sinks; sinks = sinks->next) {
+  i = 0;
+  for (sinks = elem->sinkpads; sinks; sinks = sinks->next, ++i) {
     GstSignalProcessorPad *sinkpad;
 
     sinkpad = (GstSignalProcessorPad *) sinks->data;
     g_assert (sinkpad->samples_avail > 0);
     samples_avail = MIN (samples_avail, sinkpad->samples_avail);
-    self->audio_in[sinkpad->index] = sinkpad->data;
+    if (sinkpad->channels > 1) {
+      GstSignalProcessorGroup *group = &self->group_in[in_group_index++];
+      group->interleaved_buffer = sinkpad->data;
+      /* allocate buffer for de-interleaving */
+      if (!group->buffer || group->channels < sinkpad->channels
+          || group->nframes < samples_avail) {
+        group->buffer =
+            (gfloat *) g_realloc (group->buffer,
+            samples_avail * sinkpad->channels * sizeof (gfloat));
+        memset (group->buffer, '\0',
+            samples_avail * sinkpad->channels * sizeof (gfloat));
+      }
+      g_assert (group->buffer);
+      group->channels = sinkpad->channels;
+      group->nframes = samples_avail;
+      gst_signal_processor_deinterleave_group (group, samples_avail);
+    } else {
+      self->audio_in[sinkpad->index] = sinkpad->data;
+    }
   }
 
   /* FIXME: return if samples_avail==0 ? */
@@ -571,7 +644,9 @@ gst_signal_processor_prepare (GstSignalProcessor * self, guint nframes)
       sinkpad = (GstSignalProcessorPad *) sinks->data;
       srcpad = (GstSignalProcessorPad *) srcs->data;
 
-      if (GST_BUFFER_SIZE (sinkpad->pen) == samples_avail * sizeof (gfloat)) {
+      if (sinkpad->channels == 1 && sinkpad->channels == srcpad->channels
+          && GST_BUFFER_SIZE (sinkpad->pen) ==
+          samples_avail * sizeof (gfloat)) {
         /* reusable, yay */
         g_assert (sinkpad->samples_avail == samples_avail);
         srcpad->pen = sinkpad->pen;
@@ -597,11 +672,24 @@ gst_signal_processor_prepare (GstSignalProcessor * self, guint nframes)
 
     ret =
         gst_pad_alloc_buffer_and_set_caps (GST_PAD (srcpad), -1,
-        samples_avail * sizeof (gfloat), self->caps, &srcpad->pen);
+        samples_avail * srcpad->channels * sizeof (gfloat), self->caps,
+        &srcpad->pen);
 
     if (ret != GST_FLOW_OK) {
       self->flow_state = ret;
       return 0;
+    } else if (srcpad->channels > 1) {
+      GstSignalProcessorGroup *group = &self->group_out[out_group_index++];
+      group->interleaved_buffer = (gfloat *) GST_BUFFER_DATA (srcpad->pen);
+      if (!group->buffer || group->channels < srcpad->channels
+          || group->nframes < samples_avail)
+        group->buffer =
+            (gfloat *) g_realloc (group->buffer,
+            samples_avail * srcpad->channels * sizeof (gfloat));
+      g_assert (group->buffer);
+      group->channels = srcpad->channels;
+      group->nframes = samples_avail;
+      self->pending_out++;
     } else {
       self->audio_out[srcpad->index] = (gfloat *) GST_BUFFER_DATA (srcpad->pen);
       self->pending_out++;
@@ -640,12 +728,22 @@ gst_signal_processor_update_inputs (GstSignalProcessor * self, guint nprocessed)
       /* advance ->data pointers and decrement ->samples_avail, unreffing buffer
          if no samples are left */
       sinkpad->samples_avail -= nprocessed;
-      sinkpad->data += nprocessed;      /* gfloat* arithmetic */
+      sinkpad->data += nprocessed * sinkpad->channels;  /* gfloat* arithmetic */
     }
   }
 }
 
 static void
+gst_signal_processor_update_outputs (GstSignalProcessor * self,
+    guint nprocessed)
+{
+  GstSignalProcessorClass *klass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
+  guint i;
+  for (i = 0; i < klass->num_group_out; ++i)
+    gst_signal_processor_interleave_group (&self->group_out[i], nprocessed);
+}
+
+static void
 gst_signal_processor_process (GstSignalProcessor * self, guint nframes)
 {
   GstElement *elem;
@@ -669,6 +767,7 @@ gst_signal_processor_process (GstSignalProcessor * self, guint nframes)
   klass->process (self, nframes);
 
   gst_signal_processor_update_inputs (self, nframes);
+  gst_signal_processor_update_outputs (self, nframes);
 
   return;
 
@@ -692,7 +791,8 @@ gst_signal_processor_pen_buffer (GstSignalProcessor * self, GstPad * pad,
   /* keep the reference */
   spad->pen = buffer;
   spad->data = (gfloat *) GST_BUFFER_DATA (buffer);
-  spad->samples_avail = GST_BUFFER_SIZE (buffer) / sizeof (float);
+  spad->samples_avail =
+      GST_BUFFER_SIZE (buffer) / sizeof (float) / spad->channels;
 
   g_assert (self->pending_in != 0);
 
diff --git a/gst-libs/gst/signalprocessor/gstsignalprocessor.h b/gst-libs/gst/signalprocessor/gstsignalprocessor.h
index d6f0d0b03..b01a2df87 100644
--- a/gst-libs/gst/signalprocessor/gstsignalprocessor.h
+++ b/gst-libs/gst/signalprocessor/gstsignalprocessor.h
@@ -62,10 +62,18 @@ typedef enum
 #define GST_SIGNAL_PROCESSOR_IS_RUNNING(obj) \
   (GST_SIGNAL_PROCESSOR (obj)->state == GST_SIGNAL_PROCESSOR_STATE_RUNNING)
 
+typedef struct _GstSignalProcessorGroup GstSignalProcessorGroup;
 typedef struct _GstSignalProcessor GstSignalProcessor;
 typedef struct _GstSignalProcessorClass GstSignalProcessorClass;
 
 
+struct _GstSignalProcessorGroup {
+  guint channels; /**< Number of channels in buffers */
+  guint nframes; /**< Number of frames currently allocated per channel */
+  gfloat *interleaved_buffer; /**< Interleaved buffer (c1c2c1c2...)*/
+  gfloat *buffer; /**< De-interleaved buffer (c1c1...c2c2...) */
+};
+
 struct _GstSignalProcessor {
   GstElement     element;
 
@@ -81,23 +89,32 @@ struct _GstSignalProcessor {
 
   /* pending inputs before processing can take place */
   guint pending_in;
-  /* panding outputs to be filled */
+  /* pending outputs to be filled */
   guint pending_out;
 
-  gfloat *control_in;
+  /* multi-channel signal pads */
+  GstSignalProcessorGroup *group_in;
+  GstSignalProcessorGroup *group_out;
+
+  /* single channel signal pads */
   gfloat **audio_in;
-  gfloat *control_out;
   gfloat **audio_out;
+
+  /* controls */
+  gfloat *control_in;
+  gfloat *control_out;
 };
 
 struct _GstSignalProcessorClass {
   GstElementClass parent_class;
 
   /*< public >*/
-  guint num_control_in;
+  guint num_group_in;
+  guint num_group_out;
   guint num_audio_in;
-  guint num_control_out;
   guint num_audio_out;
+  guint num_control_in;
+  guint num_control_out;
 
   guint flags;
 
@@ -114,7 +131,7 @@ struct _GstSignalProcessorClass {
 
 GType gst_signal_processor_get_type (void);
 void gst_signal_processor_class_add_pad_template (GstSignalProcessorClass *klass,
-    const gchar *name, GstPadDirection direction, guint index);
+    const gchar *name, GstPadDirection direction, guint index, guint channels);