Changeset 654 for trunk/StreamVision/AudioDevicemodule.c

Timestamp:

01/26/13 04:24:01 (11 years ago)

Author:

Nicholas Riley

Message:

AudioDevicemodule.c: Register callback for when default output device
changes.

StreamVision.py: Turn on/off the stereo when the current output device
changes to/from AirPlay.

File:

• trunk/StreamVision/AudioDevicemodule.c (modified) (3 diffs)

trunk/StreamVision/AudioDevicemodule.c

@@ -2 +2 @@
 #include <AudioToolbox/AudioServices.h>
 
-static PyObject
-*AudioDevice_default_output_device_is_airplay(PyObject *self, PyObject *args) {
+static PyObject *
+AudioDevice_default_output_device_is_airplay(PyObject *self, PyObject *args) {
   AudioObjectPropertyAddress propertyAddress;
   propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
@@ -40 +40 @@
 }
 
-// XXX device changed notifications:
-// http://stackoverflow.com/questions/9674666/
+static PyObject *default_output_device_changed_callback = NULL;
+
+OSStatus 
+output_device_changed_listener(AudioObjectID inObjectID,
+                               UInt32 inNumberAddresses,
+                               const AudioObjectPropertyAddress inAddresses[],
+                               void *inClientData) {
+  PyGILState_STATE gstate = PyGILState_Ensure();
+  PyObject_CallObject(default_output_device_changed_callback, NULL);
+  PyGILState_Release(gstate);
+
+  return noErr;
+}
+
+static PyObject *
+AudioDevice_set_default_output_device_changed_callback(PyObject *self,
+                                                       PyObject *args) {
+  PyObject *new_callback;
+  if (!PyArg_ParseTuple(args, "O", &new_callback))
+    return NULL;
+
+  if (!PyCallable_Check(new_callback)) {
+    PyErr_SetString(PyExc_TypeError, "parameter must be callable");
+    return NULL;
+  }
+  Py_INCREF(new_callback);
+  if (default_output_device_changed_callback == NULL) {
+    AudioObjectPropertyAddress propertyAddress;
+    propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
+    propertyAddress.mElement = kAudioObjectPropertyElementMaster;
+    propertyAddress.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
+
+    OSStatus err;
+    err = AudioObjectAddPropertyListener(kAudioObjectSystemObject,
+                                         &propertyAddress,
+                                         &output_device_changed_listener,
+                                         NULL);
+    if (err != noErr)
+      return PyErr_Format(PyExc_OSError,
+                          "AudioObjectAddPropertyListener failed (%ld)",
+                          (long)err);
+  } else {
+    Py_DECREF(default_output_device_changed_callback);
+  }
+  default_output_device_changed_callback = new_callback;
+  
+  Py_RETURN_NONE;
+}
 
 static PyMethodDef AudioDevicemodule_methods[] = {
@@ -48 +94 @@
    "default_output_device() -> bool or None\n\n"
    "Return whether the default CoreAudio output device is an AirPlay device."},
+  {"set_default_output_device_changed_callback",
+   AudioDevice_set_default_output_device_changed_callback, METH_VARARGS,
+   "set_default_output_device_changed_callback(callable)\n\n"
+   "Set a callback invoked when the default CoreAudio output device changes."},
   {NULL, NULL, 0, NULL}
 };