gecko-dev/media/libcubeb/0004-audiounit-ios-compile-fixes.patch

diff --git a/src/cubeb_audiounit.cpp b/src/cubeb_audiounit.cpp
--- a/src/cubeb_audiounit.cpp
+++ b/src/cubeb_audiounit.cpp
@@ -36,16 +36,25 @@
 #include <vector>
 
 using namespace std;
 
 #if MAC_OS_X_VERSION_MIN_REQUIRED < 101000
 typedef UInt32 AudioFormatFlags;
 #endif
 
+#if TARGET_OS_IPHONE
+typedef UInt32 AudioDeviceID;
+typedef UInt32 AudioObjectID;
+const UInt32 kAudioObjectUnknown = 0;
+
+#define AudioGetCurrentHostTime mach_absolute_time
+
+#endif
+
 #define AU_OUT_BUS 0
 #define AU_IN_BUS 1
 
 const char * DISPATCH_QUEUE_LABEL = "org.mozilla.cubeb";
 const char * PRIVATE_AGGREGATE_DEVICE_NAME = "CubebAggregateDevice";
 
 #ifdef ALOGV
 #undef ALOGV
@@ -60,45 +69,47 @@ const char * PRIVATE_AGGREGATE_DEVICE_NA
 #undef ALOG
 #endif
 #define ALOG(msg, ...)                                                         \
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0),   \
                  ^{                                                            \
                    LOG(msg, ##__VA_ARGS__);                                    \
                  })
 
+#if !TARGET_OS_IPHONE
 /* Testing empirically, some headsets report a minimal latency that is very
  * low, but this does not work in practice. Lie and say the minimum is 256
  * frames. */
 const uint32_t SAFE_MIN_LATENCY_FRAMES = 128;
 const uint32_t SAFE_MAX_LATENCY_FRAMES = 512;
 
 const AudioObjectPropertyAddress DEFAULT_INPUT_DEVICE_PROPERTY_ADDRESS = {
     kAudioHardwarePropertyDefaultInputDevice, kAudioObjectPropertyScopeGlobal,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
 
 const AudioObjectPropertyAddress DEFAULT_OUTPUT_DEVICE_PROPERTY_ADDRESS = {
     kAudioHardwarePropertyDefaultOutputDevice, kAudioObjectPropertyScopeGlobal,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
 
 const AudioObjectPropertyAddress DEVICE_IS_ALIVE_PROPERTY_ADDRESS = {
     kAudioDevicePropertyDeviceIsAlive, kAudioObjectPropertyScopeGlobal,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
 
 const AudioObjectPropertyAddress DEVICES_PROPERTY_ADDRESS = {
     kAudioHardwarePropertyDevices, kAudioObjectPropertyScopeGlobal,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
 
 const AudioObjectPropertyAddress INPUT_DATA_SOURCE_PROPERTY_ADDRESS = {
     kAudioDevicePropertyDataSource, kAudioDevicePropertyScopeInput,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
 
 const AudioObjectPropertyAddress OUTPUT_DATA_SOURCE_PROPERTY_ADDRESS = {
     kAudioDevicePropertyDataSource, kAudioDevicePropertyScopeOutput,
-    kAudioObjectPropertyElementMaster};
+    kAudioObjectPropertyElementMain};
+#endif
 
 typedef uint32_t device_flags_value;
 
 enum device_flags {
   DEV_UNKNOWN = 0x00,        /* Unknown */
   DEV_INPUT = 0x01,          /* Record device like mic */
   DEV_OUTPUT = 0x02,         /* Playback device like speakers */
   DEV_SYSTEM_DEFAULT = 0x04, /* System default device */
@@ -109,49 +120,51 @@ enum device_flags {
 void
 audiounit_stream_stop_internal(cubeb_stream * stm);
 static int
 audiounit_stream_start_internal(cubeb_stream * stm);
 static void
 audiounit_close_stream(cubeb_stream * stm);
 static int
 audiounit_setup_stream(cubeb_stream * stm);
+#if !TARGET_OS_IPHONE
 static vector<AudioObjectID>
 audiounit_get_devices_of_type(cubeb_device_type devtype);
 static UInt32
 audiounit_get_device_presentation_latency(AudioObjectID devid,
                                           AudioObjectPropertyScope scope);
-
-#if !TARGET_OS_IPHONE
 static AudioObjectID
 audiounit_get_default_device_id(cubeb_device_type type);
 static int
 audiounit_uninstall_device_changed_callback(cubeb_stream * stm);
 static int
 audiounit_uninstall_system_changed_callback(cubeb_stream * stm);
+#endif
+
 static void
 audiounit_reinit_stream_async(cubeb_stream * stm, device_flags_value flags);
-#endif
 
 extern cubeb_ops const audiounit_ops;
 
 struct cubeb {
   cubeb_ops const * ops = &audiounit_ops;
   owned_critical_section mutex;
   int active_streams = 0;
   uint32_t global_latency_frames = 0;
   cubeb_device_collection_changed_callback input_collection_changed_callback =
       nullptr;
   void * input_collection_changed_user_ptr = nullptr;
   cubeb_device_collection_changed_callback output_collection_changed_callback =
       nullptr;
   void * output_collection_changed_user_ptr = nullptr;
+  #if !TARGET_OS_IPHONE
   // Store list of devices to detect changes
   vector<AudioObjectID> input_device_array;
   vector<AudioObjectID> output_device_array;
+  #endif
   // The queue should be released when it’s no longer needed.
   dispatch_queue_t serial_queue =
       dispatch_queue_create(DISPATCH_QUEUE_LABEL, DISPATCH_QUEUE_SERIAL);
   // Current used channel layout
   atomic<cubeb_channel_layout> layout{CUBEB_LAYOUT_UNDEFINED};
   uint32_t channels = 0;
 };
 
@@ -181,29 +194,31 @@ to_string(io_side side)
   }
 }
 
 struct device_info {
   AudioDeviceID id = kAudioObjectUnknown;
   device_flags_value flags = DEV_UNKNOWN;
 };
 
+#if !TARGET_OS_IPHONE
 struct property_listener {
   AudioDeviceID device_id;
   const AudioObjectPropertyAddress * property_address;
   AudioObjectPropertyListenerProc callback;
   cubeb_stream * stream;
 
   property_listener(AudioDeviceID id,
                     const AudioObjectPropertyAddress * address,
                     AudioObjectPropertyListenerProc proc, cubeb_stream * stm)
       : device_id(id), property_address(address), callback(proc), stream(stm)
   {
   }
 };
+#endif
 
 struct cubeb_stream {
   explicit cubeb_stream(cubeb * context);
 
   /* Note: Must match cubeb_stream layout in cubeb.c. */
   cubeb * context;
   void * user_ptr = nullptr;
   /**/
@@ -252,32 +267,36 @@ struct cubeb_stream {
   /* Latency requested by the user. */
   uint32_t latency_frames = 0;
   atomic<uint32_t> current_latency_frames{0};
   atomic<uint32_t> total_output_latency_frames{0};
   unique_ptr<cubeb_resampler, decltype(&cubeb_resampler_destroy)> resampler;
   /* This is true if a device change callback is currently running.  */
   atomic<bool> switching_device{false};
   atomic<bool> buffer_size_change_state{false};
+  #if !TARGET_OS_IPHONE
   AudioDeviceID aggregate_device_id =
       kAudioObjectUnknown; // the aggregate device id
   AudioObjectID plugin_id =
       kAudioObjectUnknown; // used to create aggregate device
+  #endif
   /* Mixer interface */
   unique_ptr<cubeb_mixer, decltype(&cubeb_mixer_destroy)> mixer;
   /* Buffer where remixing/resampling will occur when upmixing is required */
   /* Only accessed from callback thread */
   unique_ptr<uint8_t[]> temp_buffer;
   size_t temp_buffer_size = 0; // size in bytes.
+  #if !TARGET_OS_IPHONE
   /* Listeners indicating what system events are monitored. */
   unique_ptr<property_listener> default_input_listener;
   unique_ptr<property_listener> default_output_listener;
   unique_ptr<property_listener> input_alive_listener;
   unique_ptr<property_listener> input_source_listener;
   unique_ptr<property_listener> output_source_listener;
+  #endif
 };
 
 bool
 has_input(cubeb_stream * stm)
 {
   return stm->input_stream_params.rate != 0;
 }
 
@@ -381,24 +400,16 @@ bool
 is_common_sample_rate(Float64 sample_rate)
 {
   /* Some commonly used sample rates and their multiples and divisors. */
   return sample_rate == 8000 || sample_rate == 16000 || sample_rate == 22050 ||
          sample_rate == 32000 || sample_rate == 44100 || sample_rate == 48000 ||
          sample_rate == 88200 || sample_rate == 96000;
 }
 
-#if TARGET_OS_IPHONE
-typedef UInt32 AudioDeviceID;
-typedef UInt32 AudioObjectID;
-
-#define AudioGetCurrentHostTime mach_absolute_time
-
-#endif
-
 uint64_t
 ConvertHostTimeToNanos(uint64_t host_time)
 {
   static struct mach_timebase_info timebase_info;
   static bool initialized = false;
   if (!initialized) {
     mach_timebase_info(&timebase_info);
     initialized = true;
@@ -756,23 +767,23 @@ audiounit_init(cubeb ** context, char co
 }
 
 static char const *
 audiounit_get_backend_id(cubeb * /* ctx */)
 {
   return "audiounit";
 }
 
-#if !TARGET_OS_IPHONE
 
 static int
 audiounit_stream_get_volume(cubeb_stream * stm, float * volume);
 static int
 audiounit_stream_set_volume(cubeb_stream * stm, float volume);
 
+#if !TARGET_OS_IPHONE
 static int
 audiounit_set_device_info(cubeb_stream * stm, AudioDeviceID id, io_side side)
 {
   assert(stm);
 
   device_info * info = nullptr;
   cubeb_device_type type = CUBEB_DEVICE_TYPE_UNKNOWN;
 
@@ -806,42 +817,47 @@ audiounit_set_device_info(cubeb_stream *
   }
 
   assert(info->id);
   assert(info->flags & DEV_INPUT && !(info->flags & DEV_OUTPUT) ||
          !(info->flags & DEV_INPUT) && info->flags & DEV_OUTPUT);
 
   return CUBEB_OK;
 }
+#endif
 
 static int
 audiounit_reinit_stream(cubeb_stream * stm, device_flags_value flags)
 {
   auto_lock context_lock(stm->context->mutex);
   assert((flags & DEV_INPUT && stm->input_unit) ||
          (flags & DEV_OUTPUT && stm->output_unit));
   if (!stm->shutdown) {
     audiounit_stream_stop_internal(stm);
   }
 
-  int r = audiounit_uninstall_device_changed_callback(stm);
+  int r;
+#if !TARGET_OS_IPHONE
+  r = audiounit_uninstall_device_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not uninstall all device change listeners.", stm);
   }
+#endif
 
   {
     auto_lock lock(stm->mutex);
     float volume = 0.0;
     int vol_rv = CUBEB_ERROR;
     if (stm->output_unit) {
       vol_rv = audiounit_stream_get_volume(stm, &volume);
     }
 
     audiounit_close_stream(stm);
 
+    #if !TARGET_OS_IPHONE
     /* Reinit occurs in one of the following case:
      * - When the device is not alive any more
      * - When the default system device change.
      * - The bluetooth device changed from A2DP to/from HFP/HSP profile
      * We first attempt to re-use the same device id, should that fail we will
      * default to the (potentially new) default device. */
     AudioDeviceID input_device =
         flags & DEV_INPUT ? stm->input_device.id : kAudioObjectUnknown;
@@ -861,29 +877,33 @@ audiounit_reinit_stream(cubeb_stream * s
     r = audiounit_set_device_info(stm, kAudioObjectUnknown, io_side::OUTPUT);
     if (r != CUBEB_OK) {
       LOG("(%p) Set output device info failed. This can happen when last media "
           "device is unplugged",
           stm);
       return CUBEB_ERROR;
     }
 
+    #endif
+
     if (audiounit_setup_stream(stm) != CUBEB_OK) {
       LOG("(%p) Stream reinit failed.", stm);
+      #if !TARGET_OS_IPHONE
       if (flags & DEV_INPUT && input_device != kAudioObjectUnknown) {
         // Attempt to re-use the same device-id failed, so attempt again with
         // default input device.
         audiounit_close_stream(stm);
         if (audiounit_set_device_info(stm, kAudioObjectUnknown,
                                       io_side::INPUT) != CUBEB_OK ||
             audiounit_setup_stream(stm) != CUBEB_OK) {
           LOG("(%p) Second stream reinit failed.", stm);
           return CUBEB_ERROR;
         }
       }
+      #endif
     }
 
     if (vol_rv == CUBEB_OK) {
       audiounit_stream_set_volume(stm, volume);
     }
 
     // If the stream was running, start it again.
     if (!stm->shutdown) {
@@ -909,27 +929,30 @@ audiounit_reinit_stream_async(cubeb_stre
   // Get/SetProperties method from inside notify callback
   dispatch_async(stm->context->serial_queue, ^() {
     if (stm->destroy_pending) {
       ALOG("(%p) stream pending destroy, cancelling reinit task", stm);
       return;
     }
 
     if (audiounit_reinit_stream(stm, flags) != CUBEB_OK) {
+      #if !TARGET_OS_IPHONE
       if (audiounit_uninstall_system_changed_callback(stm) != CUBEB_OK) {
         LOG("(%p) Could not uninstall system changed callback", stm);
       }
+      #endif
       stm->state_callback(stm, stm->user_ptr, CUBEB_STATE_ERROR);
       LOG("(%p) Could not reopen the stream after switching.", stm);
     }
     stm->switching_device = false;
     stm->reinit_pending = false;
   });
 }
 
+#if !TARGET_OS_IPHONE
 static char const *
 event_addr_to_string(AudioObjectPropertySelector selector)
 {
   switch (selector) {
   case kAudioHardwarePropertyDefaultOutputDevice:
     return "kAudioHardwarePropertyDefaultOutputDevice";
   case kAudioHardwarePropertyDefaultInputDevice:
     return "kAudioHardwarePropertyDefaultInputDevice";
@@ -1091,16 +1114,17 @@ audiounit_install_device_changed_callbac
           rv, stm->input_device.id);
       r = CUBEB_ERROR;
     }
   }
 
   return r;
 }
 
+#if !TARGET_OS_IPHONE
 static int
 audiounit_install_system_changed_callback(cubeb_stream * stm)
 {
   OSStatus r;
 
   if (stm->output_unit) {
     /* This event will notify us when the default audio device changes,
      * for example when the user plugs in a USB headset and the system chooses
@@ -1131,16 +1155,17 @@ audiounit_install_system_changed_callbac
           "kAudioHardwarePropertyDefaultInputDevice rv=%d",
           r);
       return CUBEB_ERROR;
     }
   }
 
   return CUBEB_OK;
 }
+#endif
 
 static int
 audiounit_uninstall_device_changed_callback(cubeb_stream * stm)
 {
   OSStatus rv;
   // Failing to uninstall listeners is not a fatal error.
   int r = CUBEB_OK;
 
@@ -1207,17 +1232,17 @@ audiounit_uninstall_system_changed_callb
 static int
 audiounit_get_acceptable_latency_range(AudioValueRange * latency_range)
 {
   UInt32 size;
   OSStatus r;
   AudioDeviceID output_device_id;
   AudioObjectPropertyAddress output_device_buffer_size_range = {
       kAudioDevicePropertyBufferFrameSizeRange, kAudioDevicePropertyScopeOutput,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
 
   output_device_id = audiounit_get_default_device_id(CUBEB_DEVICE_TYPE_OUTPUT);
   if (output_device_id == kAudioObjectUnknown) {
     LOG("Could not get default output device id.");
     return CUBEB_ERROR;
   }
 
   /* Get the buffer size range this device supports */
@@ -1228,17 +1253,16 @@ audiounit_get_acceptable_latency_range(A
                                  &size, latency_range);
   if (r != noErr) {
     LOG("AudioObjectGetPropertyData/buffer size range rv=%d", r);
     return CUBEB_ERROR;
   }
 
   return CUBEB_OK;
 }
-#endif /* !TARGET_OS_IPHONE */
 
 static AudioObjectID
 audiounit_get_default_device_id(cubeb_device_type type)
 {
   const AudioObjectPropertyAddress * adr;
   if (type == CUBEB_DEVICE_TYPE_OUTPUT) {
     adr = &DEFAULT_OUTPUT_DEVICE_PROPERTY_ADDRESS;
   } else if (type == CUBEB_DEVICE_TYPE_INPUT) {
@@ -1251,31 +1275,32 @@ audiounit_get_default_device_id(cubeb_de
   UInt32 size = sizeof(AudioDeviceID);
   if (AudioObjectGetPropertyData(kAudioObjectSystemObject, adr, 0, NULL, &size,
                                  &devid) != noErr) {
     return kAudioObjectUnknown;
   }
 
   return devid;
 }
+#endif /* !TARGET_OS_IPHONE */
 
 int
 audiounit_get_max_channel_count(cubeb * ctx, uint32_t * max_channels)
 {
 #if TARGET_OS_IPHONE
   // TODO: [[AVAudioSession sharedInstance] maximumOutputNumberOfChannels]
   *max_channels = 2;
 #else
   UInt32 size;
   OSStatus r;
   AudioDeviceID output_device_id;
   AudioStreamBasicDescription stream_format;
   AudioObjectPropertyAddress stream_format_address = {
       kAudioDevicePropertyStreamFormat, kAudioDevicePropertyScopeOutput,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
 
   assert(ctx && max_channels);
 
   output_device_id = audiounit_get_default_device_id(CUBEB_DEVICE_TYPE_OUTPUT);
   if (output_device_id == kAudioObjectUnknown) {
     return CUBEB_ERROR;
   }
 
@@ -1304,52 +1329,52 @@ audiounit_get_min_latency(cubeb * /* ctx
   AudioValueRange latency_range;
   if (audiounit_get_acceptable_latency_range(&latency_range) != CUBEB_OK) {
     LOG("Could not get acceptable latency range.");
     return CUBEB_ERROR;
   }
 
   *latency_frames =
       max<uint32_t>(latency_range.mMinimum, SAFE_MIN_LATENCY_FRAMES);
+  return CUBEB_OK;
 #endif
-
-  return CUBEB_OK;
 }
 
 static int
 audiounit_get_preferred_sample_rate(cubeb * /* ctx */, uint32_t * rate)
 {
 #if TARGET_OS_IPHONE
-  // TODO
-  return CUBEB_ERROR_NOT_SUPPORTED;
+  *rate = 44100;
+  return CUBEB_OK;
 #else
   UInt32 size;
   OSStatus r;
   Float64 fsamplerate;
   AudioDeviceID output_device_id;
   AudioObjectPropertyAddress samplerate_address = {
       kAudioDevicePropertyNominalSampleRate, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
 
   output_device_id = audiounit_get_default_device_id(CUBEB_DEVICE_TYPE_OUTPUT);
   if (output_device_id == kAudioObjectUnknown) {
     return CUBEB_ERROR;
   }
 
   size = sizeof(fsamplerate);
   r = AudioObjectGetPropertyData(output_device_id, &samplerate_address, 0, NULL,
                                  &size, &fsamplerate);
 
   if (r != noErr) {
     return CUBEB_ERROR;
   }
 
   *rate = static_cast<uint32_t>(fsamplerate);
+
+  return CUBEB_OK;
 #endif
-  return CUBEB_OK;
 }
 
 static cubeb_channel_layout
 audiounit_convert_channel_layout(AudioChannelLayout * layout)
 {
   // When having one or two channel, force mono or stereo. Some devices (namely,
   // Bose QC35, mark 1 and 2), expose a single channel mapped to the right for
   // some reason.
@@ -1380,16 +1405,19 @@ audiounit_convert_channel_layout(AudioCh
   }
 
   return cl;
 }
 
 static cubeb_channel_layout
 audiounit_get_preferred_channel_layout(AudioUnit output_unit)
 {
+  #if TARGET_OS_IPHONE
+    return CUBEB_LAYOUT_STEREO;
+  #else
   OSStatus rv = noErr;
   UInt32 size = 0;
   rv = AudioUnitGetPropertyInfo(
       output_unit, kAudioDevicePropertyPreferredChannelLayout,
       kAudioUnitScope_Output, AU_OUT_BUS, &size, nullptr);
   if (rv != noErr) {
     LOG("AudioUnitGetPropertyInfo/kAudioDevicePropertyPreferredChannelLayout "
         "rv=%d",
@@ -1404,16 +1432,17 @@ audiounit_get_preferred_channel_layout(A
       kAudioUnitScope_Output, AU_OUT_BUS, layout.get(), &size);
   if (rv != noErr) {
     LOG("AudioUnitGetProperty/kAudioDevicePropertyPreferredChannelLayout rv=%d",
         rv);
     return CUBEB_LAYOUT_UNDEFINED;
   }
 
   return audiounit_convert_channel_layout(layout.get());
+  #endif
 }
 
 static cubeb_channel_layout
 audiounit_get_current_channel_layout(AudioUnit output_unit)
 {
   OSStatus rv = noErr;
   UInt32 size = 0;
   rv = AudioUnitGetPropertyInfo(
@@ -1437,18 +1466,20 @@ audiounit_get_current_channel_layout(Aud
   }
 
   return audiounit_convert_channel_layout(layout.get());
 }
 
 static int
 audiounit_create_unit(AudioUnit * unit, device_info * device);
 
+#if !TARGET_OS_IPHONE
 static OSStatus
 audiounit_remove_device_listener(cubeb * context, cubeb_device_type devtype);
+#endif
 
 static void
 audiounit_destroy(cubeb * ctx)
 {
   {
     auto_lock lock(ctx->mutex);
 
     // Disabling this assert for bug 1083664 -- we seem to leak a stream
@@ -1460,23 +1491,25 @@ audiounit_destroy(cubeb * ctx)
 
     // Destroying a cubeb context with device collection callbacks registered
     // is misuse of the API, assert then attempt to clean up.
     assert(!ctx->input_collection_changed_callback &&
            !ctx->input_collection_changed_user_ptr &&
            !ctx->output_collection_changed_callback &&
            !ctx->output_collection_changed_user_ptr);
 
+    #if !TARGET_OS_IPHONE
     /* Unregister the callback if necessary. */
     if (ctx->input_collection_changed_callback) {
       audiounit_remove_device_listener(ctx, CUBEB_DEVICE_TYPE_INPUT);
     }
     if (ctx->output_collection_changed_callback) {
       audiounit_remove_device_listener(ctx, CUBEB_DEVICE_TYPE_OUTPUT);
     }
+    #endif
   }
 
   dispatch_release(ctx->serial_queue);
 
   delete ctx;
 }
 
 static void
@@ -1594,23 +1627,24 @@ audiounit_layout_init(cubeb_stream * stm
   }
 
   stm->context->layout = audiounit_get_current_channel_layout(stm->output_unit);
 
   audiounit_set_channel_layout(stm->output_unit, io_side::OUTPUT,
                                stm->context->layout);
 }
 
+#if !TARGET_OS_IPHONE
 static vector<AudioObjectID>
 audiounit_get_sub_devices(AudioDeviceID device_id)
 {
   vector<AudioDeviceID> sub_devices;
   AudioObjectPropertyAddress property_address = {
       kAudioAggregateDevicePropertyActiveSubDeviceList,
-      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMain};
   UInt32 size = 0;
   OSStatus rv = AudioObjectGetPropertyDataSize(device_id, &property_address, 0,
                                                nullptr, &size);
 
   if (rv != noErr) {
     sub_devices.push_back(device_id);
     return sub_devices;
   }
@@ -1629,17 +1663,17 @@ audiounit_get_sub_devices(AudioDeviceID 
 }
 
 static int
 audiounit_create_blank_aggregate_device(AudioObjectID * plugin_id,
                                         AudioDeviceID * aggregate_device_id)
 {
   AudioObjectPropertyAddress address_plugin_bundle_id = {
       kAudioHardwarePropertyPlugInForBundleID, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
   UInt32 size = 0;
   OSStatus r = AudioObjectGetPropertyDataSize(
       kAudioObjectSystemObject, &address_plugin_bundle_id, 0, NULL, &size);
   if (r != noErr) {
     LOG("AudioObjectGetPropertyDataSize/"
         "kAudioHardwarePropertyPlugInForBundleID, rv=%d",
         r);
     return CUBEB_ERROR;
@@ -1659,17 +1693,17 @@ audiounit_create_blank_aggregate_device(
     LOG("AudioObjectGetPropertyData/kAudioHardwarePropertyPlugInForBundleID, "
         "rv=%d",
         r);
     return CUBEB_ERROR;
   }
 
   AudioObjectPropertyAddress create_aggregate_device_address = {
       kAudioPlugInCreateAggregateDevice, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
   r = AudioObjectGetPropertyDataSize(
       *plugin_id, &create_aggregate_device_address, 0, nullptr, &size);
   if (r != noErr) {
     LOG("AudioObjectGetPropertyDataSize/kAudioPlugInCreateAggregateDevice, "
         "rv=%d",
         r);
     return CUBEB_ERROR;
   }
@@ -1731,17 +1765,17 @@ audiounit_create_blank_aggregate_device(
 // object is increased.
 static CFStringRef
 get_device_name(AudioDeviceID id)
 {
   UInt32 size = sizeof(CFStringRef);
   CFStringRef UIname = nullptr;
   AudioObjectPropertyAddress address_uuid = {kAudioDevicePropertyDeviceUID,
                                              kAudioObjectPropertyScopeGlobal,
-                                             kAudioObjectPropertyElementMaster};
+                                             kAudioObjectPropertyElementMain};
   OSStatus err =
       AudioObjectGetPropertyData(id, &address_uuid, 0, nullptr, &size, &UIname);
   return (err == noErr) ? UIname : NULL;
 }
 
 static int
 audiounit_set_aggregate_sub_device_list(AudioDeviceID aggregate_device_id,
                                         AudioDeviceID input_device_id,
@@ -1774,17 +1808,17 @@ audiounit_set_aggregate_sub_device_list(
       return CUBEB_ERROR;
     }
     CFArrayAppendValue(aggregate_sub_devices_array, ref);
     CFRelease(ref);
   }
 
   AudioObjectPropertyAddress aggregate_sub_device_list = {
       kAudioAggregateDevicePropertyFullSubDeviceList,
-      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMain};
   UInt32 size = sizeof(CFMutableArrayRef);
   OSStatus rv = AudioObjectSetPropertyData(
       aggregate_device_id, &aggregate_sub_device_list, 0, nullptr, size,
       &aggregate_sub_devices_array);
   CFRelease(aggregate_sub_devices_array);
   if (rv != noErr) {
     LOG("AudioObjectSetPropertyData/"
         "kAudioAggregateDevicePropertyFullSubDeviceList, rv=%d",
@@ -1796,17 +1830,17 @@ audiounit_set_aggregate_sub_device_list(
 }
 
 static int
 audiounit_set_master_aggregate_device(const AudioDeviceID aggregate_device_id)
 {
   assert(aggregate_device_id != kAudioObjectUnknown);
   AudioObjectPropertyAddress master_aggregate_sub_device = {
       kAudioAggregateDevicePropertyMasterSubDevice,
-      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMain};
 
   // Master become the 1st output sub device
   AudioDeviceID output_device_id =
       audiounit_get_default_device_id(CUBEB_DEVICE_TYPE_OUTPUT);
   const vector<AudioDeviceID> output_sub_devices =
       audiounit_get_sub_devices(output_device_id);
   CFStringRef master_sub_device = get_device_name(output_sub_devices[0]);
 
@@ -1829,17 +1863,17 @@ audiounit_set_master_aggregate_device(co
 
 static int
 audiounit_activate_clock_drift_compensation(
     const AudioDeviceID aggregate_device_id)
 {
   assert(aggregate_device_id != kAudioObjectUnknown);
   AudioObjectPropertyAddress address_owned = {
       kAudioObjectPropertyOwnedObjects, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
 
   UInt32 qualifier_data_size = sizeof(AudioObjectID);
   AudioClassID class_id = kAudioSubDeviceClassID;
   void * qualifier_data = &class_id;
   UInt32 size = 0;
   OSStatus rv = AudioObjectGetPropertyDataSize(
       aggregate_device_id, &address_owned, qualifier_data_size, qualifier_data,
       &size);
@@ -1861,17 +1895,17 @@ audiounit_activate_clock_drift_compensat
   if (rv != noErr) {
     LOG("AudioObjectGetPropertyData/kAudioObjectPropertyOwnedObjects, rv=%d",
         rv);
     return CUBEB_ERROR;
   }
 
   AudioObjectPropertyAddress address_drift = {
       kAudioSubDevicePropertyDriftCompensation, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
 
   // Start from the second device since the first is the master clock
   for (UInt32 i = 1; i < subdevices_num; ++i) {
     UInt32 drift_compensation_value = 1;
     rv = AudioObjectSetPropertyData(sub_devices[i], &address_drift, 0, nullptr,
                                     sizeof(UInt32), &drift_compensation_value);
     if (rv != noErr) {
       LOG("AudioObjectSetPropertyData/"
@@ -1930,17 +1964,17 @@ audiounit_workaround_for_airpod(cubeb_st
         &output_min_rate, &output_max_rate, &output_nominal_rate);
     LOG("(%p) Output device %u, name: %s, min: %u, max: %u, nominal rate: %u",
         stm, stm->output_device.id, output_device_info.friendly_name,
         output_min_rate, output_max_rate, output_nominal_rate);
 
     Float64 rate = input_nominal_rate;
     AudioObjectPropertyAddress addr = {kAudioDevicePropertyNominalSampleRate,
                                        kAudioObjectPropertyScopeGlobal,
-                                       kAudioObjectPropertyElementMaster};
+                                       kAudioObjectPropertyElementMain};
 
     OSStatus rv = AudioObjectSetPropertyData(stm->aggregate_device_id, &addr, 0,
                                              nullptr, sizeof(Float64), &rate);
     if (rv != noErr) {
       LOG("Non fatal error, "
           "AudioObjectSetPropertyData/kAudioDevicePropertyNominalSampleRate, "
           "rv=%d",
           rv);
@@ -2014,17 +2048,17 @@ audiounit_create_aggregate_device(cubeb_
 static int
 audiounit_destroy_aggregate_device(AudioObjectID plugin_id,
                                    AudioDeviceID * aggregate_device_id)
 {
   assert(aggregate_device_id && *aggregate_device_id != kAudioDeviceUnknown &&
          plugin_id != kAudioObjectUnknown);
   AudioObjectPropertyAddress destroy_aggregate_device_addr = {
       kAudioPlugInDestroyAggregateDevice, kAudioObjectPropertyScopeGlobal,
-      kAudioObjectPropertyElementMaster};
+      kAudioObjectPropertyElementMain};
   UInt32 size;
   OSStatus rv = AudioObjectGetPropertyDataSize(
       plugin_id, &destroy_aggregate_device_addr, 0, NULL, &size);
   if (rv != noErr) {
     LOG("AudioObjectGetPropertyDataSize/kAudioPlugInDestroyAggregateDevice, "
         "rv=%d",
         rv);
     return CUBEB_ERROR;
@@ -2037,16 +2071,17 @@ audiounit_destroy_aggregate_device(Audio
         rv);
     return CUBEB_ERROR;
   }
 
   LOG("Destroyed aggregate device %d", *aggregate_device_id);
   *aggregate_device_id = kAudioObjectUnknown;
   return CUBEB_OK;
 }
+#endif
 
 static int
 audiounit_new_unit_instance(AudioUnit * unit, device_info * device)
 {
   AudioComponentDescription desc;
   AudioComponent comp;
   OSStatus rv;
 
@@ -2173,16 +2208,19 @@ audiounit_init_input_linear_buffer(cubeb
   assert(stream->input_linear_buffer->length() == 0);
 
   return CUBEB_OK;
 }
 
 static uint32_t
 audiounit_clamp_latency(cubeb_stream * stm, uint32_t latency_frames)
 {
+  #if TARGET_OS_IPHONE
+  return latency_frames;
+  #else
   // For the 1st stream set anything within safe min-max
   assert(audiounit_active_streams(stm->context) > 0);
   if (audiounit_active_streams(stm->context) == 1) {
     return max(min<uint32_t>(latency_frames, SAFE_MAX_LATENCY_FRAMES),
                SAFE_MIN_LATENCY_FRAMES);
   }
   assert(stm->output_unit);
 
@@ -2233,18 +2271,20 @@ audiounit_clamp_latency(cubeb_stream * s
   } else if (output_buffer_size != 0) {
     upper_latency_limit = output_buffer_size;
   } else {
     upper_latency_limit = SAFE_MAX_LATENCY_FRAMES;
   }
 
   return max(min<uint32_t>(latency_frames, upper_latency_limit),
              SAFE_MIN_LATENCY_FRAMES);
+  #endif
 }
 
+#if !TARGET_OS_IPHONE
 /*
  * Change buffer size is prone to deadlock thus we change it
  * following the steps:
  * - register a listener for the buffer size property
  * - change the property
  * - wait until the listener is executed
  * - property has changed, remove the listener
  * */
@@ -2285,21 +2325,25 @@ buffer_size_changed_callback(void * inCl
           "= %d for scope %d",
           stm, au_type, new_buffer_size, inScope);
     }
     stm->buffer_size_change_state = true;
     break;
   }
   }
 }
+#endif
 
 static int
 audiounit_set_buffer_size(cubeb_stream * stm, uint32_t new_size_frames,
                           io_side side)
 {
+  #if TARGET_OS_IPHONE
+  return CUBEB_OK;
+  #else
   AudioUnit au = stm->output_unit;
   AudioUnitScope au_scope = kAudioUnitScope_Input;
   AudioUnitElement au_element = AU_OUT_BUS;
 
   if (side == io_side::INPUT) {
     au = stm->input_unit;
     au_scope = kAudioUnitScope_Output;
     au_element = AU_IN_BUS;
@@ -2377,16 +2421,17 @@ audiounit_set_buffer_size(cubeb_stream *
   if (!stm->buffer_size_change_state && count >= 30) {
     LOG("(%p) Error, did not get buffer size change callback ...", stm);
     return CUBEB_ERROR;
   }
 
   LOG("(%p) %s buffer size changed to %u frames.", stm, to_string(side),
       new_size_frames);
   return CUBEB_OK;
+  #endif
 }
 
 static int
 audiounit_configure_input(cubeb_stream * stm)
 {
   assert(stm && stm->input_unit);
 
   int r = 0;
@@ -2593,16 +2638,17 @@ audiounit_setup_stream(cubeb_stream * st
     return CUBEB_ERROR_NOT_SUPPORTED;
   }
 
   int r = 0;
 
   device_info in_dev_info = stm->input_device;
   device_info out_dev_info = stm->output_device;
 
+  #if !TARGET_OS_IPHONE
   if (has_input(stm) && has_output(stm) &&
       stm->input_device.id != stm->output_device.id) {
     r = audiounit_create_aggregate_device(stm);
     if (r != CUBEB_OK) {
       stm->aggregate_device_id = kAudioObjectUnknown;
       LOG("(%p) Create aggregate devices failed.", stm);
       // !!!NOTE: It is not necessary to return here. If it does not
       // return it will fallback to the old implementation. The intention
@@ -2610,16 +2656,20 @@ audiounit_setup_stream(cubeb_stream * st
       // it after a couple of weeks.
       return r;
     } else {
       in_dev_info.id = out_dev_info.id = stm->aggregate_device_id;
       in_dev_info.flags = DEV_INPUT;
       out_dev_info.flags = DEV_OUTPUT;
     }
   }
+  #else
+  in_dev_info.flags = DEV_SYSTEM_DEFAULT | DEV_INPUT;
+  out_dev_info.flags = DEV_SYSTEM_DEFAULT | DEV_OUTPUT;
+  #endif
 
   if (has_input(stm)) {
     r = audiounit_create_unit(&stm->input_unit, &in_dev_info);
     if (r != CUBEB_OK) {
       LOG("(%p) AudioUnit creation for input failed.", stm);
       return r;
     }
   }
@@ -2751,18 +2801,20 @@ audiounit_setup_stream(cubeb_stream * st
 
   if (stm->output_unit != NULL) {
     r = AudioUnitInitialize(stm->output_unit);
     if (r != noErr) {
       LOG("AudioUnitInitialize/output rv=%d", r);
       return CUBEB_ERROR;
     }
 
+    #if !TARGET_OS_IPHONE
     stm->current_latency_frames = audiounit_get_device_presentation_latency(
         stm->output_device.id, kAudioDevicePropertyScopeOutput);
+    #endif
 
     Float64 unit_s;
     UInt32 size = sizeof(unit_s);
     if (AudioUnitGetProperty(stm->output_unit, kAudioUnitProperty_Latency,
                              kAudioUnitScope_Global, 0, &unit_s,
                              &size) == noErr) {
       stm->current_latency_frames +=
           static_cast<uint32_t>(unit_s * stm->output_desc.mSampleRate);
@@ -2772,20 +2824,22 @@ audiounit_setup_stream(cubeb_stream * st
   if (stm->input_unit && stm->output_unit) {
     // According to the I/O hardware rate it is expected a specific pattern of
     // callbacks for example is input is 44100 and output is 48000 we expected
     // no more than 2 out callback in a row.
     stm->expected_output_callbacks_in_a_row =
         ceilf(stm->output_hw_rate / stm->input_hw_rate);
   }
 
+  #if !TARGET_OS_IPHONE
   r = audiounit_install_device_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not install all device change callback.", stm);
   }
+  #endif
 
   return CUBEB_OK;
 }
 
 cubeb_stream::cubeb_stream(cubeb * context)
     : context(context), resampler(nullptr, cubeb_resampler_destroy),
       mixer(nullptr, cubeb_mixer_destroy)
 {
@@ -2823,51 +2877,57 @@ audiounit_stream_init(cubeb * context, c
   stm->latency_frames = latency_frames;
 
   if ((input_device && !input_stream_params) ||
       (output_device && !output_stream_params)) {
     return CUBEB_ERROR_INVALID_PARAMETER;
   }
   if (input_stream_params) {
     stm->input_stream_params = *input_stream_params;
+  #if !TARGET_OS_IPHONE
     r = audiounit_set_device_info(
         stm.get(), reinterpret_cast<uintptr_t>(input_device), io_side::INPUT);
     if (r != CUBEB_OK) {
       LOG("(%p) Fail to set device info for input.", stm.get());
       return r;
     }
+  #endif
   }
   if (output_stream_params) {
     stm->output_stream_params = *output_stream_params;
+  #if !TARGET_OS_IPHONE
     r = audiounit_set_device_info(
         stm.get(), reinterpret_cast<uintptr_t>(output_device), io_side::OUTPUT);
     if (r != CUBEB_OK) {
       LOG("(%p) Fail to set device info for output.", stm.get());
       return r;
     }
+  #endif
   }
 
   {
     // It's not critical to lock here, because no other thread has been started
     // yet, but it allows to assert that the lock has been taken in
     // `audiounit_setup_stream`.
     auto_lock lock(stm->mutex);
     r = audiounit_setup_stream(stm.get());
   }
 
   if (r != CUBEB_OK) {
     LOG("(%p) Could not setup the audiounit stream.", stm.get());
     return r;
   }
 
+  #if !TARGET_OS_IPHONE
   r = audiounit_install_system_changed_callback(stm.get());
   if (r != CUBEB_OK) {
     LOG("(%p) Could not install the device change callback.", stm.get());
     return r;
   }
+  #endif
 
   *stream = stm.release();
   LOG("(%p) Cubeb stream init successful.", *stream);
   return CUBEB_OK;
 }
 
 static void
 audiounit_close_stream(cubeb_stream * stm)
@@ -2886,54 +2946,60 @@ audiounit_close_stream(cubeb_stream * st
     AudioUnitUninitialize(stm->output_unit);
     AudioComponentInstanceDispose(stm->output_unit);
     stm->output_unit = nullptr;
   }
 
   stm->resampler.reset();
   stm->mixer.reset();
 
+  #if !TARGET_OS_IPHONE
   if (stm->aggregate_device_id != kAudioObjectUnknown) {
     audiounit_destroy_aggregate_device(stm->plugin_id,
                                        &stm->aggregate_device_id);
     stm->aggregate_device_id = kAudioObjectUnknown;
   }
+  #endif
 }
 
 static void
 audiounit_stream_destroy_internal(cubeb_stream * stm)
 {
   stm->context->mutex.assert_current_thread_owns();
 
+#if !TARGET_OS_IPHONE
   int r = audiounit_uninstall_system_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not uninstall the device changed callback", stm);
   }
   r = audiounit_uninstall_device_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not uninstall all device change listeners", stm);
   }
+#endif
 
   auto_lock lock(stm->mutex);
   audiounit_close_stream(stm);
   assert(audiounit_active_streams(stm->context) >= 1);
   audiounit_decrement_active_streams(stm->context);
 }
 
 static void
 audiounit_stream_destroy(cubeb_stream * stm)
 {
+  #if !TARGET_OS_IPHONE
   int r = audiounit_uninstall_system_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not uninstall the device changed callback", stm);
   }
   r = audiounit_uninstall_device_changed_callback(stm);
   if (r != CUBEB_OK) {
     LOG("(%p) Could not uninstall all device change listeners", stm);
   }
+  #endif
 
   if (!stm->shutdown.load()) {
     auto_lock context_lock(stm->context->mutex);
     audiounit_stream_stop_internal(stm);
     stm->shutdown = true;
   }
 
   stm->destroy_pending = true;
@@ -3081,16 +3147,17 @@ convert_uint32_into_string(UInt32 data)
   // Reverse 0xWXYZ into 0xZYXW.
   str[0] = (char)(data >> 24);
   str[1] = (char)(data >> 16);
   str[2] = (char)(data >> 8);
   str[3] = (char)(data);
   return str;
 }
 
+#if !TARGET_OS_IPHONE
 int
 audiounit_get_default_device_datasource(cubeb_device_type type, UInt32 * data)
 {
   AudioDeviceID id = audiounit_get_default_device_id(type);
   if (id == kAudioObjectUnknown) {
     return CUBEB_ERROR;
   }
 
@@ -3102,38 +3169,43 @@ audiounit_get_default_device_datasource(
                                       : &OUTPUT_DATA_SOURCE_PROPERTY_ADDRESS,
       0, NULL, &size, data);
   if (r != noErr) {
     *data = 0;
   }
 
   return CUBEB_OK;
 }
+#endif
 
 int
 audiounit_get_default_device_name(cubeb_stream * stm,
                                   cubeb_device * const device,
                                   cubeb_device_type type)
 {
+#if TARGET_OS_IPHONE
+  return CUBEB_ERROR_NOT_SUPPORTED;
+#else
   assert(stm);
   assert(device);
 
   UInt32 data;
   int r = audiounit_get_default_device_datasource(type, &data);
   if (r != CUBEB_OK) {
     return r;
   }
   char ** name = type == CUBEB_DEVICE_TYPE_INPUT ? &device->input_name
                                                  : &device->output_name;
   *name = convert_uint32_into_string(data).release();
   if (!strlen(*name)) { // empty string.
     LOG("(%p) name of %s device is empty!", stm,
         type == CUBEB_DEVICE_TYPE_INPUT ? "input" : "output");
   }
   return CUBEB_OK;
+  #endif
 }
 
 int
 audiounit_stream_get_current_device(cubeb_stream * stm,
                                     cubeb_device ** const device)
 {
 #if TARGET_OS_IPHONE
   // TODO
@@ -3178,16 +3250,17 @@ audiounit_stream_register_device_changed
   auto_lock dev_cb_lock(stream->device_changed_callback_lock);
   /* Note: second register without unregister first causes 'nope' error.
    * Current implementation requires unregister before register a new cb. */
   assert(!device_changed_callback || !stream->device_changed_callback);
   stream->device_changed_callback = device_changed_callback;
   return CUBEB_OK;
 }
 
+#if !TARGET_OS_IPHONE
 static char *
 audiounit_strref_to_cstr_utf8(CFStringRef strref)
 {
   CFIndex len, size;
   char * ret;
   if (strref == NULL) {
     return NULL;
   }
@@ -3199,22 +3272,24 @@ audiounit_strref_to_cstr_utf8(CFStringRe
 
   if (!CFStringGetCString(strref, ret, size, kCFStringEncodingUTF8)) {
     delete[] ret;
     ret = NULL;
   }
 
   return ret;
 }
-
+#endif
+
+#if !TARGET_OS_IPHONE
 static uint32_t
 audiounit_get_channel_count(AudioObjectID devid, AudioObjectPropertyScope scope)
 {
   AudioObjectPropertyAddress adr = {0, scope,
-                                    kAudioObjectPropertyElementMaster};
+                                    kAudioObjectPropertyElementMain};
   UInt32 size = 0;
   uint32_t i, ret = 0;
 
   adr.mSelector = kAudioDevicePropertyStreamConfiguration;
 
   if (AudioObjectGetPropertyDataSize(devid, &adr, 0, NULL, &size) == noErr &&
       size > 0) {
     AudioBufferList * list = static_cast<AudioBufferList *>(alloca(size));
@@ -3230,17 +3305,17 @@ audiounit_get_channel_count(AudioObjectI
 
 static void
 audiounit_get_available_samplerate(AudioObjectID devid,
                                    AudioObjectPropertyScope scope,
                                    uint32_t * min, uint32_t * max,
                                    uint32_t * def)
 {
   AudioObjectPropertyAddress adr = {0, scope,
-                                    kAudioObjectPropertyElementMaster};
+                                    kAudioObjectPropertyElementMain};
 
   adr.mSelector = kAudioDevicePropertyNominalSampleRate;
   if (AudioObjectHasProperty(devid, &adr)) {
     UInt32 size = sizeof(Float64);
     Float64 fvalue = 0.0;
     if (AudioObjectGetPropertyData(devid, &adr, 0, NULL, &size, &fvalue) ==
         noErr) {
       *def = fvalue;
@@ -3272,17 +3347,17 @@ audiounit_get_available_samplerate(Audio
   }
 }
 
 static UInt32
 audiounit_get_device_presentation_latency(AudioObjectID devid,
                                           AudioObjectPropertyScope scope)
 {
   AudioObjectPropertyAddress adr = {0, scope,
-                                    kAudioObjectPropertyElementMaster};
+                                    kAudioObjectPropertyElementMain};
   UInt32 size, dev, stream = 0;
   AudioStreamID sid[1];
 
   adr.mSelector = kAudioDevicePropertyLatency;
   size = sizeof(UInt32);
   if (AudioObjectGetPropertyData(devid, &adr, 0, NULL, &size, &dev) != noErr) {
     dev = 0;
   }
@@ -3297,28 +3372,32 @@ audiounit_get_device_presentation_latenc
 
   return dev + stream;
 }
 
 static int
 audiounit_create_device_from_hwdev(cubeb_device_info * dev_info,
                                    AudioObjectID devid, cubeb_device_type type)
 {
-  AudioObjectPropertyAddress adr = {0, 0, kAudioObjectPropertyElementMaster};
+  AudioObjectPropertyAddress adr = {0, 0, kAudioObjectPropertyElementMain};
   UInt32 size;
 
   if (type == CUBEB_DEVICE_TYPE_OUTPUT) {
     adr.mScope = kAudioDevicePropertyScopeOutput;
   } else if (type == CUBEB_DEVICE_TYPE_INPUT) {
     adr.mScope = kAudioDevicePropertyScopeInput;
   } else {
     return CUBEB_ERROR;
   }
 
+  #if TARGET_OS_IPHONE
+  UINT32 ch = 2;
+  #else
   UInt32 ch = audiounit_get_channel_count(devid, adr.mScope);
+  #endif
   if (ch == 0) {
     return CUBEB_ERROR;
   }
 
   PodZero(dev_info, 1);
 
   CFStringRef device_id_str = nullptr;
   size = sizeof(CFStringRef);
@@ -3412,17 +3491,26 @@ audiounit_create_device_from_hwdev(cubeb
 
 bool
 is_aggregate_device(cubeb_device_info * device_info)
 {
   assert(device_info->friendly_name);
   return !strncmp(device_info->friendly_name, PRIVATE_AGGREGATE_DEVICE_NAME,
                   strlen(PRIVATE_AGGREGATE_DEVICE_NAME));
 }
-
+#endif
+
+#if TARGET_OS_IPHONE
+static int
+audiounit_enumerate_devices(cubeb * /* context */, cubeb_device_type type,
+                            cubeb_device_collection * collection)
+{
+  return CUBEB_ERROR_NOT_SUPPORTED;
+}
+#else
 static int
 audiounit_enumerate_devices(cubeb * /* context */, cubeb_device_type type,
                             cubeb_device_collection * collection)
 {
   vector<AudioObjectID> input_devs;
   vector<AudioObjectID> output_devs;
 
   // Count number of input and output devices.  This is not
@@ -3478,29 +3566,35 @@ audiounit_enumerate_devices(cubeb * /* c
 
 static void
 audiounit_device_destroy(cubeb_device_info * device)
 {
   delete[] device->device_id;
   delete[] device->friendly_name;
   delete[] device->vendor_name;
 }
+#endif
 
 static int
 audiounit_device_collection_destroy(cubeb * /* context */,
                                     cubeb_device_collection * collection)
 {
+  #if TARGET_OS_IPHONE
+  return CUBEB_ERROR_NOT_SUPPORTED;
+  #else
   for (size_t i = 0; i < collection->count; i++) {
     audiounit_device_destroy(&collection->device[i]);
   }
   delete[] collection->device;
 
   return CUBEB_OK;
+  #endif
 }
 
+#if !TARGET_OS_IPHONE
 static vector<AudioObjectID>
 audiounit_get_devices_of_type(cubeb_device_type devtype)
 {
   UInt32 size = 0;
   OSStatus ret = AudioObjectGetPropertyDataSize(
       kAudioObjectSystemObject, &DEVICES_PROPERTY_ADDRESS, 0, NULL, &size);
   if (ret != noErr) {
     return vector<AudioObjectID>();
@@ -3653,17 +3747,28 @@ audiounit_remove_device_listener(cubeb *
       context->output_collection_changed_callback) {
     return noErr;
   }
   /* Note: unregister a non registered cb is not a problem, not checking. */
   return AudioObjectRemovePropertyListener(
       kAudioObjectSystemObject, &DEVICES_PROPERTY_ADDRESS,
       audiounit_collection_changed_callback, context);
 }
-
+#endif
+
+#if TARGET_OS_IPHONE
+int
+audiounit_register_device_collection_changed(
+    cubeb * context, cubeb_device_type devtype,
+    cubeb_device_collection_changed_callback collection_changed_callback,
+    void * user_ptr)
+{
+  return CUBEB_ERROR_NOT_SUPPORTED;
+}
+#else
 int
 audiounit_register_device_collection_changed(
     cubeb * context, cubeb_device_type devtype,
     cubeb_device_collection_changed_callback collection_changed_callback,
     void * user_ptr)
 {
   if (devtype == CUBEB_DEVICE_TYPE_UNKNOWN) {
     return CUBEB_ERROR_INVALID_PARAMETER;
@@ -3673,16 +3778,17 @@ audiounit_register_device_collection_cha
   if (collection_changed_callback) {
     ret = audiounit_add_device_listener(context, devtype,
                                         collection_changed_callback, user_ptr);
   } else {
     ret = audiounit_remove_device_listener(context, devtype);
   }
   return (ret == noErr) ? CUBEB_OK : CUBEB_ERROR;
 }
+#endif
 
 cubeb_ops const audiounit_ops = {
     /*.init =*/audiounit_init,
     /*.get_backend_id =*/audiounit_get_backend_id,
     /*.get_max_channel_count =*/audiounit_get_max_channel_count,
     /*.get_min_latency =*/audiounit_get_min_latency,
     /*.get_preferred_sample_rate =*/audiounit_get_preferred_sample_rate,
     /*.get_supported_input_processing_params =*/NULL,