osxaudio: Support audio device provider on osx

https://bugzilla.gnome.org/show_bug.cgi?id=753265

8 files changed, 495 insertions, 11 deletions

diff --git a/sys/osxaudio/Makefile.am b/sys/osxaudio/Makefile.am
index 12b7d03fd..45c720088 100644
--- a/sys/osxaudio/Makefile.am
+++ b/sys/osxaudio/Makefile.am
@@ -19,6 +19,7 @@ libgstosxaudio_la_LIBADD = 			  \
 libgstosxaudio_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS) -Wl,-framework,CoreAudio  -Wl,-framework,AudioToolbox
 
 if !HAVE_IOS
+libgstosxaudio_la_SOURCES += gstosxaudiodeviceprovider.c
 libgstosxaudio_la_LDFLAGS += -Wl,-framework,AudioUnit -Wl,-framework,CoreServices
 endif
 
diff --git a/sys/osxaudio/gstosxaudio.c b/sys/osxaudio/gstosxaudio.c
index c48b03f8f..99dfdbf8d 100644
--- a/sys/osxaudio/gstosxaudio.c
+++ b/sys/osxaudio/gstosxaudio.c
@@ -30,6 +30,9 @@
 #include "gstosxaudioelement.h"
 #include "gstosxaudiosink.h"
 #include "gstosxaudiosrc.h"
+#ifndef HAVE_IOS
+#include "gstosxaudiodeviceprovider.h"
+#endif
 
 static gboolean
 plugin_init (GstPlugin * plugin)
@@ -42,6 +45,11 @@ plugin_init (GstPlugin * plugin)
           GST_TYPE_OSX_AUDIO_SRC)) {
     return FALSE;
   }
+#ifndef HAVE_IOS
+  if (!gst_device_provider_register (plugin, "osxaudiodeviceprovider",
+          GST_RANK_PRIMARY, GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER))
+    return FALSE;
+#endif
 
   return TRUE;
 }
diff --git a/sys/osxaudio/gstosxaudiodeviceprovider.c b/sys/osxaudio/gstosxaudiodeviceprovider.c
new file mode 100644
index 000000000..52a222f49
--- /dev/null
+++ b/sys/osxaudio/gstosxaudiodeviceprovider.c
@@ -0,0 +1,380 @@
+/* GStreamer
+ * Copyright (C) 2016 Hyunjun Ko <zzoon@igalia.com>
+ *
+ * gstosxaudiodeviceprovider.c: OSX audio device probing and monitoring
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <gst/audio/audio.h>
+#include "gstosxaudiosrc.h"
+#include "gstosxaudiosink.h"
+#include "gstosxaudiodeviceprovider.h"
+
+static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_OSX_AUDIO_SRC_CAPS)
+    );
+
+static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_OSX_AUDIO_SINK_CAPS)
+    );
+
+static GstOsxAudioDevice *gst_osx_audio_device_new (AudioDeviceID device_id,
+    const gchar * device_name, GstOsxAudioDeviceType type,
+    GstCoreAudio * core_audio);
+
+G_DEFINE_TYPE (GstOsxAudioDeviceProvider, gst_osx_audio_device_provider,
+    GST_TYPE_DEVICE_PROVIDER);
+
+static GList *gst_osx_audio_device_provider_probe (GstDeviceProvider *
+    provider);
+
+static void
+gst_osx_audio_device_provider_class_init (GstOsxAudioDeviceProviderClass *
+    klass)
+{
+  GstDeviceProviderClass *dm_class = GST_DEVICE_PROVIDER_CLASS (klass);
+
+  dm_class->probe = gst_osx_audio_device_provider_probe;
+
+  gst_device_provider_class_set_static_metadata (dm_class,
+      "OSX Audio Device Provider", "Source/Sink/Audio",
+      "List and monitor OSX audio source and sink devices",
+      "Hyunjun Ko <zzoon@igalia.com>");
+}
+
+static void
+gst_osx_audio_device_provider_init (GstOsxAudioDeviceProvider * provider)
+{
+}
+
+static GstOsxAudioDevice *
+gst_osx_audio_device_provider_probe_device (GstOsxAudioDeviceProvider *
+    provider, AudioDeviceID device_id, const gchar * device_name,
+    GstOsxAudioDeviceType type)
+{
+  GstOsxAudioDevice *device = NULL;
+  GstCoreAudio *core_audio;
+
+  core_audio = gst_core_audio_new (NULL);
+  core_audio->is_src = type == GST_OSX_AUDIO_DEVICE_TYPE_SOURCE ? TRUE : FALSE;
+  core_audio->device_id = device_id;
+
+  if (!gst_core_audio_open (core_audio)) {
+    GST_ERROR ("CoreAudio device could not be opened");
+    goto done;
+  }
+
+  device = gst_osx_audio_device_new (device_id, device_name, type, core_audio);
+
+  gst_core_audio_close (core_audio);
+
+done:
+  g_object_unref (core_audio);
+
+  return device;
+}
+
+static inline gchar *
+_audio_device_get_name (AudioDeviceID device_id, gboolean output)
+{
+  OSStatus status = noErr;
+  UInt32 propertySize = 0;
+  gchar *device_name = NULL;
+  AudioObjectPropertyScope prop_scope;
+
+  AudioObjectPropertyAddress deviceNameAddress = {
+    kAudioDevicePropertyDeviceName,
+    kAudioDevicePropertyScopeOutput,
+    kAudioObjectPropertyElementMaster
+  };
+
+  prop_scope = output ? kAudioDevicePropertyScopeOutput :
+      kAudioDevicePropertyScopeInput;
+
+  deviceNameAddress.mScope = prop_scope;
+
+  /* Get the length of the device name */
+  status = AudioObjectGetPropertyDataSize (device_id,
+      &deviceNameAddress, 0, NULL, &propertySize);
+  if (status != noErr) {
+    goto beach;
+  }
+
+  /* Get the name of the device */
+  device_name = (gchar *) g_malloc (propertySize);
+  status = AudioObjectGetPropertyData (device_id,
+      &deviceNameAddress, 0, NULL, &propertySize, device_name);
+  if (status != noErr) {
+    g_free (device_name);
+    device_name = NULL;
+  }
+
+beach:
+  return device_name;
+}
+
+static inline gboolean
+_audio_device_has_output (AudioDeviceID device_id)
+{
+  OSStatus status = noErr;
+  UInt32 propertySize;
+
+  AudioObjectPropertyAddress streamsAddress = {
+    kAudioDevicePropertyStreams,
+    kAudioDevicePropertyScopeOutput,
+    kAudioObjectPropertyElementMaster
+  };
+
+  status = AudioObjectGetPropertyDataSize (device_id,
+      &streamsAddress, 0, NULL, &propertySize);
+  if (status != noErr) {
+    return FALSE;
+  }
+  if (propertySize == 0) {
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+static inline AudioDeviceID *
+_audio_system_get_devices (gint * ndevices)
+{
+  OSStatus status = noErr;
+  UInt32 propertySize = 0;
+  AudioDeviceID *devices = NULL;
+
+  AudioObjectPropertyAddress audioDevicesAddress = {
+    kAudioHardwarePropertyDevices,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+  };
+
+  status = AudioObjectGetPropertyDataSize (kAudioObjectSystemObject,
+      &audioDevicesAddress, 0, NULL, &propertySize);
+  if (status != noErr) {
+    GST_WARNING ("failed getting number of devices: %d", (int) status);
+    return NULL;
+  }
+
+  *ndevices = propertySize / sizeof (AudioDeviceID);
+
+  devices = (AudioDeviceID *) g_malloc (propertySize);
+  if (devices) {
+    status = AudioObjectGetPropertyData (kAudioObjectSystemObject,
+        &audioDevicesAddress, 0, NULL, &propertySize, devices);
+    if (status != noErr) {
+      GST_WARNING ("failed getting the list of devices: %d", (int) status);
+      g_free (devices);
+      *ndevices = 0;
+      return NULL;
+    }
+  }
+
+  return devices;
+}
+
+static GList *
+gst_osx_audio_device_provider_probe (GstDeviceProvider * provider)
+{
+  GstOsxAudioDeviceProvider *self = GST_OSX_AUDIO_DEVICE_PROVIDER (provider);
+  GList *devices = NULL;
+  GstOsxAudioDevice *device = NULL;
+  AudioDeviceID *osx_devices = NULL;
+  gint i, ndevices = 0;
+
+  osx_devices = _audio_system_get_devices (&ndevices);
+
+  if (ndevices < 1) {
+    GST_WARNING ("no audio output devices found");
+    goto done;
+  }
+
+  GST_INFO ("found %d audio device(s)", ndevices);
+
+  for (i = 0; i < ndevices; i++) {
+    gchar *device_name;
+    GstOsxAudioDeviceType type = GST_OSX_AUDIO_DEVICE_TYPE_INVALID;
+
+    if ((device_name = _audio_device_get_name (osx_devices[i], FALSE))) {
+      if (!_audio_device_has_output (osx_devices[i])) {
+        GST_DEBUG ("Input Device ID: %u Name: %s",
+            (unsigned) osx_devices[i], device_name);
+        type = GST_OSX_AUDIO_DEVICE_TYPE_SOURCE;
+
+      } else {
+        GST_DEBUG ("Output Device ID: %u Name: %s",
+            (unsigned) osx_devices[i], device_name);
+        type = GST_OSX_AUDIO_DEVICE_TYPE_SINK;
+      }
+
+      device =
+          gst_osx_audio_device_provider_probe_device (self, osx_devices[i],
+          device_name, type);
+      if (device) {
+        gst_object_ref_sink (device);
+        devices = g_list_prepend (devices, device);
+      }
+
+      g_free (device_name);
+    }
+  }
+
+done:
+  g_free (osx_devices);
+
+  return devices;
+}
+
+enum
+{
+  PROP_DEVICE_ID = 1,
+};
+
+G_DEFINE_TYPE (GstOsxAudioDevice, gst_osx_audio_device, GST_TYPE_DEVICE);
+
+static void gst_osx_audio_device_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_osx_audio_device_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static GstElement *gst_osx_audio_device_create_element (GstDevice * device,
+    const gchar * name);
+
+static void
+gst_osx_audio_device_class_init (GstOsxAudioDeviceClass * klass)
+{
+  GstDeviceClass *dev_class = GST_DEVICE_CLASS (klass);
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  dev_class->create_element = gst_osx_audio_device_create_element;
+
+  object_class->get_property = gst_osx_audio_device_get_property;
+  object_class->set_property = gst_osx_audio_device_set_property;
+
+  g_object_class_install_property (object_class, PROP_DEVICE_ID,
+      g_param_spec_int ("device-id", "Device ID", "Device ID of input device",
+          0, G_MAXINT, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+}
+
+static void
+gst_osx_audio_device_init (GstOsxAudioDevice * device)
+{
+}
+
+static GstElement *
+gst_osx_audio_device_create_element (GstDevice * device, const gchar * name)
+{
+  GstOsxAudioDevice *osxdev = GST_OSX_AUDIO_DEVICE (device);
+  GstElement *elem;
+
+  elem = gst_element_factory_make (osxdev->element, name);
+  g_object_set (elem, "device", osxdev->device_id, NULL);
+
+  return elem;
+}
+
+static GstOsxAudioDevice *
+gst_osx_audio_device_new (AudioDeviceID device_id, const gchar * device_name,
+    GstOsxAudioDeviceType type, GstCoreAudio * core_audio)
+{
+  GstOsxAudioDevice *gstdev;
+  const gchar *element_name = NULL;
+  const gchar *klass = NULL;
+  GstCaps *template_caps, *caps;
+
+  g_return_val_if_fail (device_id > 0, NULL);
+  g_return_val_if_fail (device_name, NULL);
+
+  switch (type) {
+    case GST_OSX_AUDIO_DEVICE_TYPE_SOURCE:
+      element_name = "osxaudiosrc";
+      klass = "Audio/Source";
+
+      template_caps = gst_static_pad_template_get_caps (&src_factory);
+      caps = gst_core_audio_probe_caps (core_audio, template_caps);
+      gst_caps_unref (template_caps);
+
+      break;
+    case GST_OSX_AUDIO_DEVICE_TYPE_SINK:
+      element_name = "osxaudiosink";
+      klass = "Audio/Sink";
+
+      template_caps = gst_static_pad_template_get_caps (&sink_factory);
+      caps = gst_core_audio_probe_caps (core_audio, template_caps);
+      gst_caps_unref (template_caps);
+
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+
+  gstdev = g_object_new (GST_TYPE_OSX_AUDIO_DEVICE, "device-id",
+      device_id, "display-name", device_name, "caps", caps, "device-class",
+      klass, NULL);
+
+  gstdev->element = element_name;
+
+
+  return gstdev;
+}
+
+static void
+gst_osx_audio_device_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstOsxAudioDevice *device;
+
+  device = GST_OSX_AUDIO_DEVICE_CAST (object);
+
+  switch (prop_id) {
+    case PROP_DEVICE_ID:
+      g_value_set_int (value, device->device_id);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+
+static void
+gst_osx_audio_device_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstOsxAudioDevice *device;
+
+  device = GST_OSX_AUDIO_DEVICE_CAST (object);
+
+  switch (prop_id) {
+    case PROP_DEVICE_ID:
+      device->device_id = g_value_get_int (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
diff --git a/sys/osxaudio/gstosxaudiodeviceprovider.h b/sys/osxaudio/gstosxaudiodeviceprovider.h
new file mode 100644
index 000000000..bd54178ee
--- /dev/null
+++ b/sys/osxaudio/gstosxaudiodeviceprovider.h
@@ -0,0 +1,91 @@
+/* GStreamer
+ * Copyright (C) 2016 Hyunjun Ko <zzoon@igalia.com>
+ *
+ * gstosxaudiodeviceeprovider.h: OSX audio probing and monitoring
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef __GST_OSX_AUDIO_DEIVCE_PROVIDER_H__
+#define __GST_OSX_AUDIO_DEIVCE_PROVIDER_H__
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include "gstosxcoreaudiocommon.h"
+
+G_BEGIN_DECLS
+typedef struct _GstOsxAudioDeviceProvider GstOsxAudioDeviceProvider;
+typedef struct _GstOsxAudioDeviceProviderClass GstOsxAudioDeviceProviderClass;
+
+#define GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER                 (gst_osx_audio_device_provider_get_type())
+#define GST_IS_OSX_AUDIO_DEVICE_PROVIDER(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER))
+#define GST_IS_OSX_AUDIO_DEVICE_PROVIDER_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER))
+#define GST_OSX_AUDIO_DEVICE_PROVIDER_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER, GstOsxAudioDeviceProviderClass))
+#define GST_OSX_AUDIO_DEVICE_PROVIDER(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_OSX_AUDIO_DEVICE_PROVIDER, GstOsxAudioDeviceProvider))
+#define GST_OSX_AUDIO_DEVICE_PROVIDER_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_DEVICE_PROVIDER, GstOsxAudioDeviceProviderClass))
+#define GST_OSX_AUDIO_DEVICE_PROVIDER_CAST(obj)            ((GstOsxAudioDeviceProvider *)(obj))
+
+struct _GstOsxAudioDeviceProvider
+{
+  GstDeviceProvider parent;
+};
+
+struct _GstOsxAudioDeviceProviderClass
+{
+  GstDeviceProviderClass parent_class;
+};
+
+GType gst_osx_audio_device_provider_get_type (void);
+
+typedef struct _GstOsxAudioDevice GstOsxAudioDevice;
+typedef struct _GstOsxAudioDeviceClass GstOsxAudioDeviceClass;
+
+#define GST_TYPE_OSX_AUDIO_DEVICE                 (gst_osx_audio_device_get_type())
+#define GST_IS_OSX_AUDIO_DEVICE(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_OSX_AUDIO_DEVICE))
+#define GST_IS_OSX_AUDIO_DEVICE_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_OSX_AUDIO_DEVICE))
+#define GST_OSX_AUDIO_DEVICE_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_OSX_AUDIO_DEVICE, GstOsxAudioClass))
+#define GST_OSX_AUDIO_DEVICE(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_OSX_AUDIO_DEVICE, GstOsxAudioDevice))
+#define GST_OSX_AUDIO_DEVICE_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_DEVICE, GstOsxAudioDeviceClass))
+#define GST_OSX_AUDIO_DEVICE_CAST(obj)            ((GstOsxAudioDevice *)(obj))
+
+typedef enum
+{
+  GST_OSX_AUDIO_DEVICE_TYPE_INVALID = 0,
+  GST_OSX_AUDIO_DEVICE_TYPE_SOURCE,
+  GST_OSX_AUDIO_DEVICE_TYPE_SINK
+} GstOsxAudioDeviceType;
+
+struct _GstOsxAudioDevice
+{
+  GstDevice parent;
+
+  const gchar *element;
+  AudioDeviceID device_id;
+};
+
+struct _GstOsxAudioDeviceClass
+{
+  GstDeviceClass parent_class;
+};
+
+GType gst_osx_audio_device_get_type (void);
+
+G_END_DECLS
+#endif /* __GST_OSX_AUDIO_DEIVCE_PROVIDER_H__ */
diff --git a/sys/osxaudio/gstosxaudiosink.c b/sys/osxaudio/gstosxaudiosink.c
index 3e9b07cad..a1fd15875 100644
--- a/sys/osxaudio/gstosxaudiosink.c
+++ b/sys/osxaudio/gstosxaudiosink.c
@@ -96,13 +96,7 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("audio/x-raw, "
-        "format = (string) " GST_AUDIO_FORMATS_ALL ", "
-        "layout = (string) interleaved, "
-        "rate = (int) [1, MAX], "
-        "channels = (int) [1, 9];"
-        "audio/x-ac3, framed = (boolean) true;"
-        "audio/x-dts, framed = (boolean) true")
+    GST_STATIC_CAPS (GST_OSX_AUDIO_SINK_CAPS)
     );
 
 static void gst_osx_audio_sink_set_property (GObject * object, guint prop_id,
diff --git a/sys/osxaudio/gstosxaudiosink.h b/sys/osxaudio/gstosxaudiosink.h
index 1428d763a..2f55c4d2e 100644
--- a/sys/osxaudio/gstosxaudiosink.h
+++ b/sys/osxaudio/gstosxaudiosink.h
@@ -57,6 +57,14 @@
 
 G_BEGIN_DECLS
 
+#define GST_OSX_AUDIO_SINK_CAPS "audio/x-raw, " \
+        "format = (string) " GST_AUDIO_FORMATS_ALL ", " \
+        "layout = (string) interleaved, " \
+        "rate = (int) [1, MAX], " \
+        "channels = (int) [1, 9];" \
+        "audio/x-ac3, framed = (boolean) true;" \
+        "audio/x-dts, framed = (boolean) true"
+
 #define GST_TYPE_OSX_AUDIO_SINK \
   (gst_osx_audio_sink_get_type())
 #define GST_OSX_AUDIO_SINK(obj) \
diff --git a/sys/osxaudio/gstosxaudiosrc.c b/sys/osxaudio/gstosxaudiosrc.c
index 0c1cfbe5c..4e56778bc 100644
--- a/sys/osxaudio/gstosxaudiosrc.c
+++ b/sys/osxaudio/gstosxaudiosrc.c
@@ -82,10 +82,7 @@ enum
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("audio/x-raw, "
-        "format = (string) " GST_AUDIO_FORMATS_ALL ", "
-        "layout = (string) interleaved, "
-        "rate = (int) [1, MAX], " "channels = (int) [1, MAX]")
+    GST_STATIC_CAPS (GST_OSX_AUDIO_SRC_CAPS)
     );
 
 static void gst_osx_audio_src_set_property (GObject * object, guint prop_id,
diff --git a/sys/osxaudio/gstosxaudiosrc.h b/sys/osxaudio/gstosxaudiosrc.h
index fb32aa2a4..9d825b028 100644
--- a/sys/osxaudio/gstosxaudiosrc.h
+++ b/sys/osxaudio/gstosxaudiosrc.h
@@ -51,6 +51,11 @@
 
 G_BEGIN_DECLS
 
+#define GST_OSX_AUDIO_SRC_CAPS "audio/x-raw, " \
+        "format = (string) " GST_AUDIO_FORMATS_ALL ", " \
+        "layout = (string) interleaved, " \
+        "rate = (int) [1, MAX], " "channels = (int) [1, MAX]"
+
 #define GST_TYPE_OSX_AUDIO_SRC \
   (gst_osx_audio_src_get_type())
 #define GST_OSX_AUDIO_SRC(obj) \