osxaudio: Don't set the format on an initialized AudioUnit

We need to initialize the AudioUnit early to be able to probe the
underlying device, but according to the AudioUnitInitialize() and
AudioUnitUninitialize() documentation, format changes should be done
while the AudioUnit is uninitialized. So we explicitly uninitialize the
AudioUnit during a format change and reinitialize it when we're done.

4 files changed, 47 insertions, 3 deletions

diff --git a/sys/osxaudio/gstosxcoreaudio.c b/sys/osxaudio/gstosxcoreaudio.c
index b425fb247..10fcd9c36 100644
--- a/sys/osxaudio/gstosxcoreaudio.c
+++ b/sys/osxaudio/gstosxcoreaudio.c
@@ -168,7 +168,8 @@ gst_core_audio_open (GstCoreAudio * core_audio)
         "listener for AudioUnit: %d", (int) status);
   }
 
-  /* Initialize the AudioUnit */
+  /* Initialize the AudioUnit. We keep the audio unit initialized early so that
+   * we can probe the underlying device. */
   status = AudioUnitInitialize (core_audio->audiounit);
   if (status) {
     GST_ERROR_OBJECT (core_audio, "Failed to initialize AudioUnit: %d",
diff --git a/sys/osxaudio/gstosxcoreaudiocommon.c b/sys/osxaudio/gstosxcoreaudiocommon.c
index b81af9cb1..39d03ac5b 100644
--- a/sys/osxaudio/gstosxcoreaudiocommon.c
+++ b/sys/osxaudio/gstosxcoreaudiocommon.c
@@ -238,6 +238,7 @@ _core_audio_set_property (GstCoreAudio * core_audio, AudioUnitPropertyID inID,
   return TRUE;
 }
 
+/* The AudioUnit must be uninitialized before calling this */
 gboolean
 gst_core_audio_set_channel_layout (GstCoreAudio * core_audio,
     gint channels, GstCaps * caps)
@@ -297,6 +298,7 @@ gst_core_audio_set_channel_layout (GstCoreAudio * core_audio,
   return ret;
 }
 
+/* The AudioUnit must be uninitialized before calling this */
 gboolean
 gst_core_audio_set_format (GstCoreAudio * core_audio,
     AudioStreamBasicDescription format)
diff --git a/sys/osxaudio/gstosxcoreaudiohal.c b/sys/osxaudio/gstosxcoreaudiohal.c
index a05f38461..c1fefcc3c 100644
--- a/sys/osxaudio/gstosxcoreaudiohal.c
+++ b/sys/osxaudio/gstosxcoreaudiohal.c
@@ -1123,6 +1123,15 @@ gst_core_audio_initialize_impl (GstCoreAudio * core_audio,
     gboolean is_passthrough, guint32 * frame_size)
 {
   gboolean ret = FALSE;
+  OSStatus status;
+
+  /* Uninitialize the AudioUnit before changing formats */
+  status = AudioUnitUninitialize (core_audio->audiounit);
+  if (status) {
+    GST_ERROR_OBJECT (core_audio, "Failed to uninitialize AudioUnit: %d",
+        (int) status);
+    return FALSE;
+  }
 
   core_audio->is_passthrough = is_passthrough;
   if (is_passthrough) {
@@ -1157,9 +1166,18 @@ gst_core_audio_initialize_impl (GstCoreAudio * core_audio,
   ret = TRUE;
 
 done:
+  /* Format changed, initialise the AudioUnit again */
+  status = AudioUnitInitialize (core_audio->audiounit);
+  if (status) {
+    GST_ERROR_OBJECT (core_audio, "Failed to initialize AudioUnit: %d",
+        (int) status);
+    ret = FALSE;
+  }
+
   if (ret) {
     GST_DEBUG_OBJECT (core_audio, "osxbuf ring buffer acquired");
   }
+
   return ret;
 }
 
diff --git a/sys/osxaudio/gstosxcoreaudioremoteio.c b/sys/osxaudio/gstosxcoreaudioremoteio.c
index d2f2f0bde..76b0eba32 100644
--- a/sys/osxaudio/gstosxcoreaudioremoteio.c
+++ b/sys/osxaudio/gstosxcoreaudioremoteio.c
@@ -84,10 +84,22 @@ gst_core_audio_initialize_impl (GstCoreAudio * core_audio,
     AudioStreamBasicDescription format, GstCaps * caps,
     gboolean is_passthrough, guint32 * frame_size)
 {
+  gboolean ret = FALSE;
+  OSStatus status;
+
+  /* Uninitialize the AudioUnit before changing formats */
+  status = AudioUnitUninitialize (core_audio->audiounit);
+  if (status) {
+    GST_ERROR_OBJECT (core_audio, "Failed to uninitialize AudioUnit: %d",
+        (int) status);
+    return FALSE;
+  }
+
   core_audio->is_passthrough = is_passthrough;
   core_audio->stream_idx = 0;
+
   if (!gst_core_audio_set_format (core_audio, format))
-    return FALSE;
+    goto done;
 
   /* FIXME: Use kAudioSessionProperty_CurrentHardwareSampleRate and
    * kAudioSessionProperty_CurrentHardwareIOBufferDuration with property
@@ -96,7 +108,18 @@ gst_core_audio_initialize_impl (GstCoreAudio * core_audio,
   *frame_size = 4196;
 
   GST_DEBUG_OBJECT (core_audio, "osxbuf ring buffer acquired");
-  return TRUE;
+  ret = TRUE;
+
+done:
+  /* Format changed, initialise the AudioUnit again */
+  status = AudioUnitInitialize (core_audio->audiounit);
+  if (status) {
+    GST_ERROR_OBJECT (core_audio, "Failed to initialize AudioUnit: %d",
+        (int) status);
+    ret = FALSE;
+  }
+
+  return ret;
 }
 
 static gboolean