audio/out: add AudioUnit output driver for iOS

audio/out/ao.c

@@ -35,6 +35,7 @@
 #include "common/global.h"
 
 extern const struct ao_driver audio_out_oss;
+extern const struct ao_driver audio_out_audiounit;
 extern const struct ao_driver audio_out_coreaudio;
 extern const struct ao_driver audio_out_coreaudio_exclusive;
 extern const struct ao_driver audio_out_rsound;
@@ -52,6 +53,9 @@ extern const struct ao_driver audio_out_sdl;
 
 static const struct ao_driver * const audio_out_drivers[] = {
 // native:
+#if HAVE_AUDIOUNIT
+    &audio_out_audiounit,
+#endif
 #if HAVE_COREAUDIO
     &audio_out_coreaudio,
 #endif

audio/out/ao_audiounit.m

@@ -0,0 +1,201 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mpv 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+#include "ao.h"
+#include "internal.h"
+#include "audio/format.h"
+#include "osdep/timer.h"
+#include "options/m_option.h"
+#include "misc/ring.h"
+#include "common/msg.h"
+#include "ao_coreaudio_utils.h"
+#include "ao_coreaudio_chmap.h"
+
+#import <AudioUnit/AudioUnit.h>
+#import <CoreAudio/CoreAudioTypes.h>
+#import <AudioToolbox/AudioToolbox.h>
+#import <AVFoundation/AVFoundation.h>
+#import <mach/mach_time.h>
+
+struct priv {
+    AudioUnit audio_unit;
+    double device_latency;
+};
+
+static OSStatus render_cb_lpcm(void *ctx, AudioUnitRenderActionFlags *aflags,
+                              const AudioTimeStamp *ts, UInt32 bus,
+                              UInt32 frames, AudioBufferList *buffer_list)
+{
+    struct ao *ao = ctx;
+    struct priv *p = ao->priv;
+    void *planes[MP_NUM_CHANNELS] = {0};
+
+    for (int n = 0; n < ao->num_planes; n++)
+        planes[n] = buffer_list->mBuffers[n].mData;
+
+    int64_t end = mp_time_us();
+    end += ca_frames_to_us(ao, frames);
+    end += p->device_latency * 1e6;
+    ao_read_data(ao, planes, frames, end);
+    return noErr;
+}
+
+static bool init_audiounit(struct ao *ao)
+{
+    AudioStreamBasicDescription asbd;
+    OSStatus err;
+    uint32_t size;
+    struct priv *p = ao->priv;
+    AVAudioSession *instance = AVAudioSession.sharedInstance;
+    AVAudioSessionPortDescription *port = nil;
+    NSInteger maxChannels = instance.maximumOutputNumberOfChannels;
+    NSInteger prefChannels = MIN(maxChannels, ao->channels.num);
+
+    [instance setCategory:AVAudioSessionCategoryPlayback error:nil];
+    [instance setMode:AVAudioSessionModeMoviePlayback error:nil];
+    [instance setActive:YES error:nil];
+    [instance setPreferredOutputNumberOfChannels:prefChannels error:nil];
+
+    AudioComponentDescription desc = (AudioComponentDescription) {
+        .componentType         = kAudioUnitType_Output,
+        .componentSubType      = kAudioUnitSubType_RemoteIO,
+        .componentManufacturer = kAudioUnitManufacturer_Apple,
+        .componentFlags        = 0,
+        .componentFlagsMask    = 0,
+    };
+
+    AudioComponent comp = AudioComponentFindNext(NULL, &desc);
+    if (comp == NULL) {
+        MP_ERR(ao, "unable to find audio component\n");
+        goto coreaudio_error;
+    }
+
+    err = AudioComponentInstanceNew(comp, &(p->audio_unit));
+    CHECK_CA_ERROR("unable to open audio component");
+
+    err = AudioUnitInitialize(p->audio_unit);
+    CHECK_CA_ERROR_L(coreaudio_error_component,
+                     "unable to initialize audio unit");
+
+    if (af_fmt_is_spdif(ao->format) || instance.outputNumberOfChannels <= 2) {
+        ao->channels = (struct mp_chmap)MP_CHMAP_INIT_STEREO;
+    } else {
+        port = instance.currentRoute.outputs.firstObject;
+        if (port.channels.count == 2 &&
+            port.channels[0].channelLabel == kAudioChannelLabel_Unknown) {
+            // Special case when using an HDMI adapter. The iOS device will
+            // perform SPDIF conversion for us, so send all available channels
+            // using the AC3 mapping.
+            ao->channels = (struct mp_chmap)MP_CHMAP6(FL, FC, FR, SL, SR, LFE);
+        } else {
+            ao->channels.num = (uint8_t)port.channels.count;
+            for (AVAudioSessionChannelDescription *ch in port.channels) {
+              ao->channels.speaker[ch.channelNumber - 1] =
+                  ca_label_to_mp_speaker_id(ch.channelLabel);
+            }
+        }
+    }
+
+    ca_fill_asbd(ao, &asbd);
+    size = sizeof(AudioStreamBasicDescription);
+    err = AudioUnitSetProperty(p->audio_unit,
+                               kAudioUnitProperty_StreamFormat,
+                               kAudioUnitScope_Input, 0, &asbd, size);
+
+    CHECK_CA_ERROR_L(coreaudio_error_audiounit,
+                     "unable to set the input format on the audio unit");
+
+    AURenderCallbackStruct render_cb = (AURenderCallbackStruct) {
+        .inputProc       = render_cb_lpcm,
+        .inputProcRefCon = ao,
+    };
+
+    err = AudioUnitSetProperty(p->audio_unit,
+                               kAudioUnitProperty_SetRenderCallback,
+                               kAudioUnitScope_Input, 0, &render_cb,
+                               sizeof(AURenderCallbackStruct));
+
+    CHECK_CA_ERROR_L(coreaudio_error_audiounit,
+                     "unable to set render callback on audio unit");
+
+    return true;
+
+coreaudio_error_audiounit:
+    AudioUnitUninitialize(p->audio_unit);
+coreaudio_error_component:
+    AudioComponentInstanceDispose(p->audio_unit);
+coreaudio_error:
+    return false;
+}
+
+static void stop(struct ao *ao)
+{
+    struct priv *p = ao->priv;
+    OSStatus err = AudioOutputUnitStop(p->audio_unit);
+    CHECK_CA_WARN("can't stop audio unit");
+}
+
+static void start(struct ao *ao)
+{
+    struct priv *p = ao->priv;
+    AVAudioSession *instance = AVAudioSession.sharedInstance;
+
+    p->device_latency = [instance outputLatency];
+
+    OSStatus err = AudioOutputUnitStart(p->audio_unit);
+    CHECK_CA_WARN("can't start audio unit");
+}
+
+static void uninit(struct ao *ao)
+{
+    struct priv *p = ao->priv;
+    AudioOutputUnitStop(p->audio_unit);
+    AudioUnitUninitialize(p->audio_unit);
+    AudioComponentInstanceDispose(p->audio_unit);
+
+    [AVAudioSession.sharedInstance
+        setActive:NO
+        withOptions:AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation
+        error:nil];
+}
+
+static int init(struct ao *ao)
+{
+    if (!init_audiounit(ao))
+        goto coreaudio_error;
+
+    return CONTROL_OK;
+
+coreaudio_error:
+    return CONTROL_ERROR;
+}
+
+#define OPT_BASE_STRUCT struct priv
+
+const struct ao_driver audio_out_audiounit = {
+    .description    = "AudioUnit (iOS)",
+    .name           = "audiounit",
+    .uninit         = uninit,
+    .init           = init,
+    .pause          = stop,
+    .resume         = start,
+    .priv_size      = sizeof(struct priv),
+    .options = (const struct m_option[]){
+        {0}
+    },
+};

audio/out/ao_coreaudio_chmap.c

@@ -56,7 +56,7 @@ static const int speaker_map[][2] = {
     { 0,                                       -1                 },
 };
 
-static int ca_label_to_mp_speaker_id(AudioChannelLabel label)
+int ca_label_to_mp_speaker_id(AudioChannelLabel label)
 {
     for (int i = 0; speaker_map[i][1] >= 0; i++)
         if (speaker_map[i][0] == label)
@@ -64,6 +64,7 @@ static int ca_label_to_mp_speaker_id(AudioChannelLabel label)
     return -1;
 }
 
+#if HAVE_COREAUDIO
 static void ca_log_layout(struct ao *ao, int l, AudioChannelLayout *layout)
 {
     if (!mp_msg_test(ao->log, l))
@@ -327,3 +328,4 @@ void ca_get_active_chmap(struct ao *ao, AudioDeviceID device, int channel_count,
     MP_WARN(ao, "mismatching channels - falling back to %s\n",
             mp_chmap_to_str(out_map));
 }
+#endif

audio/out/ao_coreaudio_chmap.h

@@ -22,8 +22,12 @@
 
 struct mp_chmap;
 
+int ca_label_to_mp_speaker_id(AudioChannelLabel label);
+
+#if HAVE_COREAUDIO
 bool ca_init_chmap(struct ao *ao, AudioDeviceID device);
 void ca_get_active_chmap(struct ao *ao, AudioDeviceID device, int channel_count,
                          struct mp_chmap *out_map);
+#endif
 
 #endif

audio/out/ao_coreaudio_utils.c

@@ -22,15 +22,17 @@
  * on CoreAudio but not the AUHAL (such as using AudioQueue services).
  */
 
-#include <CoreAudio/HostTime.h>
-
 #include "audio/out/ao_coreaudio_utils.h"
-#include "audio/out/ao_coreaudio_properties.h"
 #include "osdep/timer.h"
 #include "osdep/endian.h"
 #include "osdep/semaphore.h"
 #include "audio/format.h"
 
+#if HAVE_COREAUDIO
+#include "audio/out/ao_coreaudio_properties.h"
+#include <CoreAudio/HostTime.h>
+#endif
+
 CFStringRef cfstr_from_cstr(char *str)
 {
     return CFStringCreateWithCString(NULL, str, CA_CFSTR_ENCODING);
@@ -46,6 +48,7 @@ char *cfstr_get_cstr(CFStringRef cfstr)
     return buffer;
 }
 
+#if HAVE_COREAUDIO
 static bool ca_is_output_device(struct ao *ao, AudioDeviceID dev)
 {
     size_t n_buffers;
@@ -142,6 +145,7 @@ OSStatus ca_select_device(struct ao *ao, char* name, AudioDeviceID *device)
 coreaudio_error:
     return err;
 }
+#endif
 
 bool check_ca_st(struct ao *ao, int level, OSStatus code, const char *message)
 {
@@ -306,6 +310,7 @@ int64_t ca_frames_to_us(struct ao *ao, uint32_t frames)
     return frames / (float) ao->samplerate * 1e6;
 }
 
+#if HAVE_COREAUDIO
 int64_t ca_get_latency(const AudioTimeStamp *ts)
 {
     uint64_t out = AudioConvertHostTimeToNanos(ts->mHostTime);
@@ -522,4 +527,4 @@ coreaudio_error:
     sem_destroy(&wakeup);
     return format_set;
 }
-
+#endif

audio/out/ao_coreaudio_utils.h

@@ -49,7 +49,9 @@ bool check_ca_st(struct ao *ao, int level, OSStatus code, const char *message);
     } while (0)
 
 void ca_get_device_list(struct ao *ao, struct ao_device_list *list);
+#if HAVE_COREAUDIO
 OSStatus ca_select_device(struct ao *ao, char* name, AudioDeviceID *device);
+#endif
 
 bool ca_formatid_is_compressed(uint32_t formatid);
 void ca_fill_asbd(struct ao *ao, AudioStreamBasicDescription *asbd);
@@ -63,8 +65,11 @@ bool ca_asbd_is_better(AudioStreamBasicDescription *req,
                        AudioStreamBasicDescription *new);
 
 int64_t ca_frames_to_us(struct ao *ao, uint32_t frames);
+#if HAVE_COREAUDIO
 int64_t ca_get_latency(const AudioTimeStamp *ts);
+#endif
 
+#if HAVE_COREAUDIO
 bool ca_stream_supports_compressed(struct ao *ao, AudioStreamID stream);
 OSStatus ca_lock_device(AudioDeviceID device, pid_t *pid);
 OSStatus ca_unlock_device(AudioDeviceID device, pid_t *pid);
@@ -73,5 +78,6 @@ OSStatus ca_enable_mixing(struct ao *ao, AudioDeviceID device, bool changed);
 int64_t ca_get_device_latency_us(struct ao *ao, AudioDeviceID device);
 bool ca_change_physical_format_sync(struct ao *ao, AudioStreamID stream,
                                     AudioStreamBasicDescription change_format);
+#endif
 
 #endif /* MPV_COREAUDIO_UTILS_H */

waftools/fragments/audiounit.c

@@ -0,0 +1,15 @@
+#include <AudioToolbox/AudioToolbox.h>
+#include <AudioUnit/AudioUnit.h>
+#include <CoreAudio/CoreAudioTypes.h>
+
+int main(int argc, char **argv)
+{
+    AudioComponentDescription desc = (AudioComponentDescription) {
+        .componentType         = kAudioUnitType_Output,
+        .componentSubType      = kAudioUnitSubType_RemoteIO,
+        .componentManufacturer = kAudioUnitManufacturer_Apple,
+    };
+
+    AudioComponentFindNext(NULL, &desc);
+    return 0;
+}

wscript

@@ -606,6 +606,13 @@ audio_output_features = [
         'func': check_cc(
             fragment=load_fragment('coreaudio.c'),
             framework_name=['CoreFoundation', 'CoreAudio', 'AudioUnit', 'AudioToolbox'])
+    }, {
+        'name': '--audiounit',
+        'desc': 'AudioUnit output for iOS',
+        'deps': ['atomics'],
+        'func': check_cc(
+            fragment=load_fragment('audiounit.c'),
+            framework_name=['Foundation', 'AudioToolbox'])
     }, {
         'name': '--wasapi',
         'desc': 'WASAPI audio output',

wscript_build.py

@@ -127,6 +127,9 @@ def build(ctx):
         ( "audio/filter/tools.c" ),
         ( "audio/out/ao.c" ),
         ( "audio/out/ao_alsa.c",                 "alsa" ),
+        ( "audio/out/ao_audiounit.m",            "audiounit" ),
+        ( "audio/out/ao_coreaudio_chmap.c",      "audiounit" ),
+        ( "audio/out/ao_coreaudio_utils.c",      "audiounit" ),
         ( "audio/out/ao_coreaudio.c",            "coreaudio" ),
         ( "audio/out/ao_coreaudio_chmap.c",      "coreaudio" ),
         ( "audio/out/ao_coreaudio_exclusive.c",  "coreaudio" ),