LV2 preset support.

ext/lv2/gstlv2.c

@@ -167,6 +167,13 @@ gst_lv2_build_positions (GstLV2Group * group)
   return positions;
 }
 
+static gint
+gst_lv2_compare_symbol (gconstpointer a, gconstpointer b, gpointer data)
+{
+  return strcmp (slv2_value_as_string ((SLV2Value) a),
+      slv2_value_as_string ((SLV2Value) b));
+}
+
 static void
 gst_lv2_base_init (gpointer g_class)
 {
@@ -176,13 +183,16 @@ gst_lv2_base_init (gpointer g_class)
   GstElementDetails *details;
   SLV2Plugin lv2plugin;
   SLV2Value val;
-  SLV2Values values, sub_values;
+  SLV2Values values = NULL, sub_values = NULL;
+  SLV2Value prev = NULL;
   GstLV2Group *group = NULL;
   GstAudioChannelPosition position = GST_AUDIO_CHANNEL_POSITION_INVALID;
   GstAudioChannelPosition mono_position = GST_AUDIO_CHANNEL_POSITION_FRONT_MONO;
   GstAudioChannelPosition *positions = NULL;
-  guint j, in_pad_index = 0, out_pad_index = 0;
+  guint j, in_pad_index = 0, out_pad_index = 0, in_prop_index = 0;
   gchar *klass_tags;
+  GTree *control_port_indices = g_tree_new_full (gst_lv2_compare_symbol,
+      NULL, NULL, free);
 
   GST_DEBUG ("base_init %p", g_class);
 
@@ -210,8 +220,17 @@ gst_lv2_base_init (gpointer g_class)
     const SLV2Port port = slv2_plugin_get_port_by_index (lv2plugin, j);
     const gboolean is_input = slv2_port_is_a (lv2plugin, port, input_class);
     gboolean in_group = FALSE;
-    struct _GstLV2Port desc = { j, 0 };
+    struct _GstLV2Port desc;
-    values = slv2_port_get_value (lv2plugin, port, in_group_pred);
+    desc.index = j;
+    desc.pad = 0;
+    desc.role = NULL;
+    desc.position = GST_AUDIO_CHANNEL_POSITION_INVALID;
+
+    /* we only care about audio port groups (for multi-channel) */
+    if (slv2_port_is_a (lv2plugin, port, audio_class))
+      values = slv2_port_get_value (lv2plugin, port, in_group_pred);
+    else
+      values = NULL;
 
     if (slv2_values_size (values) > 0) {
       /* port is part of a group */
@@ -272,15 +291,22 @@ gst_lv2_base_init (gpointer g_class)
        * is illegal so we just ignore it */
       if (slv2_port_is_a (lv2plugin, port, audio_class)) {
         desc.pad = is_input ? in_pad_index++ : out_pad_index++;
-        if (is_input)
+        if (is_input) {
           g_array_append_val (klass->audio_in_ports, desc);
-        else
+        } else {
           g_array_append_val (klass->audio_out_ports, desc);
+        }
       } else if (slv2_port_is_a (lv2plugin, port, control_class)) {
-        if (is_input)
+        if (is_input) {
+          gint *prop_num = malloc (sizeof (gint));
+          desc.pad = in_prop_index++;
+          *prop_num = desc.pad;
+          g_tree_insert (control_port_indices, slv2_port_get_symbol (lv2plugin,
+                  port), prop_num);
           g_array_append_val (klass->control_in_ports, desc);
-        else
+        } else {
           g_array_append_val (klass->control_out_ports, desc);
+        }
       } else {
         /* unknown port type */
         continue;
@@ -352,6 +378,59 @@ gst_lv2_base_init (gpointer g_class)
         j, 1, &mono_position);
   }
 
+  /* find presets */
+  values = slv2_plugin_query_sparql (lv2plugin,
+      "PREFIX pset: <http://lv2plug.in/ns/dev/presets#>\n"
+      "PREFIX dc:   <http://dublincore.org/documents/dcmi-namespace/>\n"
+      "SELECT ?preset ?name ?sym ?val WHERE {\n"
+      "  <>      pset:hasPreset ?preset .\n"
+      "  ?preset dc:title       ?name ;\n"
+      "          lv2:port       ?port .\n"
+      "  ?port   lv2:symbol     ?sym ;\n"
+      "          pset:value     ?val .\n" "}\n");
+  for (; !slv2_results_finished (values); slv2_results_next (values)) {
+    SLV2Value preset = slv2_results_get_binding_value (values, 0);
+    SLV2Value name = slv2_results_get_binding_value (values, 1);
+    SLV2Value sym = slv2_results_get_binding_value (values, 2);
+    SLV2Value val = slv2_results_get_binding_value (values, 3);
+    GstLV2Preset *p = NULL;
+    const gint *index = NULL;
+    GstLV2PresetValue preset_val;
+
+    if (!klass->presets)
+      klass->presets = g_array_new (FALSE, TRUE, sizeof (GstLV2Preset));
+
+    if (!slv2_value_equals (prev, preset)) {
+      struct _GstLV2Preset new_preset;
+      new_preset.uri = preset;
+      new_preset.name = name;
+      new_preset.values = NULL;
+      g_array_append_val (klass->presets, new_preset);
+    }
+    p = &g_array_index (klass->presets, GstLV2Preset, klass->presets->len - 1);
+    prev = p->uri;
+
+    /* we don't understand non-float port values */
+    if (!slv2_value_is_float (val)) {
+      continue;
+    }
+
+    /* look up port by symbol (we need the index) */
+    index = (gint *) g_tree_lookup (control_port_indices, sym);
+    if (!index) {
+      /* we don't know about this port, just ignore it */
+      continue;
+    }
+
+    preset_val.index = *index;
+    preset_val.value = slv2_value_as_float (val);
+    if (!p->values)
+      p->values = g_array_new (FALSE, TRUE, sizeof (GstLV2PresetValue));
+    g_array_append_val (p->values, preset_val);
+  }
+
+  g_tree_destroy (control_port_indices);
+
   /* construct the element details struct */
   details = g_new0 (GstElementDetails, 1);
   val = slv2_plugin_get_name (lv2plugin);
@@ -466,7 +545,8 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
 {
   GObjectClass *gobject_class;
   GstSignalProcessorClass *gsp_class;
-  gint i;
+  GParamSpec *preset_spec;
+  gint i, offset = 1;
 
   GST_DEBUG ("class_init %p", klass);
 
@@ -483,7 +563,22 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
 
   klass->plugin = lv2plugin;
 
-  /* register properties */
+  /* register preset property */
+  if (klass->presets) {
+    gint perms =
+        G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT |
+        GST_PARAM_CONTROLLABLE;
+    preset_spec =
+        g_param_spec_int ("preset", "preset", "preset", 0,
+        klass->presets->len - 1, 0, perms);
+    g_object_class_install_property (G_OBJECT_CLASS (klass), 1, preset_spec);
+
+    /* if there is a preset property, then port properties are offset by 2
+     * relative to lv2 port index (rather than 1) */
+    offset = 2;
+  }
+
+  /* register control port properties */
 
   for (i = 0; i < gsp_class->num_control_in; i++) {
     GParamSpec *p;
@@ -491,8 +586,8 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
     p = gst_lv2_class_get_param_spec (klass,
         g_array_index (klass->control_in_ports, GstLV2Port, i).index);
 
-    /* properties have an offset of 1 */
+    /* control properties have an offset of (offset) */
-    g_object_class_install_property (G_OBJECT_CLASS (klass), i + 1, p);
+    g_object_class_install_property (G_OBJECT_CLASS (klass), i + offset, p);
   }
 
   for (i = 0; i < gsp_class->num_control_out; i++) {
@@ -501,9 +596,9 @@ gst_lv2_class_init (GstLV2Class * klass, SLV2Plugin lv2plugin)
     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 */
+    /* control properties have an offset of (offset), and we already added num_control_in */
     g_object_class_install_property (G_OBJECT_CLASS (klass),
-        gsp_class->num_control_in + i + 1, p);
+        gsp_class->num_control_in + i + offset, p);
   }
 }
 
@@ -513,6 +608,7 @@ gst_lv2_init (GstLV2 * lv2, GstLV2Class * klass)
   lv2->plugin = klass->plugin;
   lv2->instance = NULL;
   lv2->activated = FALSE;
+  lv2->current_preset = 0;
 }
 
 static void
@@ -521,13 +617,44 @@ gst_lv2_set_property (GObject * object, guint prop_id, const GValue * value,
 {
   GstSignalProcessor *gsp;
   GstSignalProcessorClass *gsp_class;
+  GstLV2 *lv2;
+  GstLV2Class *lv2_class;
+  gint i;
 
   gsp = GST_SIGNAL_PROCESSOR (object);
   gsp_class = GST_SIGNAL_PROCESSOR_GET_CLASS (object);
+  lv2 = (GstLV2 *) gsp;
+  lv2_class = (GstLV2Class *) gsp_class;
 
-  /* remember, properties have an offset of 1 */
+  /* remember, properties have an offset of 1, or 2 if there are presets */
   prop_id--;
 
+  if (lv2_class->presets) {
+    if (prop_id == 0) {
+      GstLV2Preset *preset;
+      gint num = g_value_get_int (value);
+      if (num > lv2_class->presets->len) {
+        GST_WARNING ("Preset number out of range\n");
+        return;
+      }
+      preset = &g_array_index (lv2_class->presets, GstLV2Preset, num);
+
+      /* apply preset controls */
+      for (i = 0; i < preset->values->len; ++i) {
+        GstLV2PresetValue *preset_value =
+            &g_array_index (preset->values, GstLV2PresetValue, i);
+        GstLV2Port *desc =
+            &g_array_index (lv2_class->control_in_ports, GstLV2Port,
+            preset_value->index);
+        gsp->control_in[prop_id] = preset_value->value;
+      }
+      lv2->current_preset = num;
+      return;
+    } else {
+      prop_id--;
+    }
+  }
+
   /* only input ports */
   g_return_if_fail (prop_id < gsp_class->num_control_in);
 
@@ -553,13 +680,25 @@ gst_lv2_get_property (GObject * object, guint prop_id, GValue * value,
 {
   GstSignalProcessor *gsp;
   GstSignalProcessorClass *gsp_class;
+  GstLV2 *lv2;
+  GstLV2Class *lv2_class;
   gfloat *controls;
 
   gsp = GST_SIGNAL_PROCESSOR (object);
   gsp_class = GST_SIGNAL_PROCESSOR_GET_CLASS (object);
+  lv2 = (GstLV2 *) gsp;
+  lv2_class = (GstLV2Class *) gsp_class;
 
   /* remember, properties have an offset of 1 */
   prop_id--;
+  if (lv2_class->presets != NULL) {
+    if (prop_id == 0) {
+      g_value_set_int (value, lv2->current_preset);
+      return;
+    } else {
+      prop_id--;
+    }
+  }
 
   if (prop_id < gsp_class->num_control_in) {
     controls = gsp->control_in;

ext/lv2/gstlv2.h

@@ -48,6 +48,8 @@ typedef struct _GstLV2 GstLV2;
 typedef struct _GstLV2Class GstLV2Class;
 typedef struct _GstLV2Group GstLV2Group;
 typedef struct _GstLV2Port GstLV2Port;
+typedef struct _GstLV2Preset GstLV2Preset;
+typedef struct _GstLV2PresetValue GstLV2PresetValue;
 
 
 struct _GstLV2 {
@@ -57,6 +59,7 @@ struct _GstLV2 {
   SLV2Instance instance;
 
   gboolean activated;
+  gint     current_preset;
 };
 
 struct _GstLV2Group {
@@ -69,11 +72,23 @@ struct _GstLV2Group {
 
 struct _GstLV2Port {
   gint index; /**< LV2 port index (on LV2 plugin) */
-  gint pad; /**< Gst pad index (iff not part of a group) */
+  gint pad; /**< Gst pad (iff not part of a group) or property index */
   SLV2Value role; /**< Channel position / port role */
   GstAudioChannelPosition position; /**< Channel position */
 };
 
+
+struct _GstLV2PresetValue {
+  gint index; /**< LV2 port index */
+  gfloat value; /**< Port value */
+};
+
+struct _GstLV2Preset {
+  SLV2Value uri;
+  SLV2Value name;
+  GArray *values; /**< Array of GstLV2PresetValue */
+};
+
 struct _GstLV2Class {
   GstSignalProcessorClass parent_class;
 
@@ -86,6 +101,7 @@ struct _GstLV2Class {
   GArray *control_in_ports; /**< Array of GstLV2Port */
   GArray *control_out_ports; /**< Array of GstLV2Port */
 
+  GArray *presets; /**< Array of GstLV2Preset */
 };