From 7c032bde3e6473902bbda2aea65be4bfb9d68802 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Mon, 6 Jul 2015 17:49:28 +0200
Subject: ao_coreaudio: fix device latency, share the code

ao_coreaudio (using AudioUnit) accounted only for part of the latency -
move the code in ao_coreaudio_exclusive to utils, and use that for the
AudioUnit code.

(There's still the question why CoreAudio and AudioUnit require you to
jump through hoops this much, but apparently that's how it is.)
---
 audio/out/ao_coreaudio.c           |  6 +-----
 audio/out/ao_coreaudio_exclusive.c | 19 +------------------
 audio/out/ao_coreaudio_utils.c     | 22 ++++++++++++++++++++++
 audio/out/ao_coreaudio_utils.h     |  1 +
 4 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/audio/out/ao_coreaudio.c b/audio/out/ao_coreaudio.c
index 1cf38326a2..c592c0ef84 100644
--- a/audio/out/ao_coreaudio.c
+++ b/audio/out/ao_coreaudio.c
@@ -56,12 +56,8 @@ static int64_t ca_get_hardware_latency(struct ao *ao) {
             &size);
     CHECK_CA_ERROR("cannot get audio unit latency");
 
-    uint32_t frames = 0;
-    err = CA_GET_O(p->device, kAudioDevicePropertyLatency, &frames);
-    CHECK_CA_ERROR("cannot get device latency");
-
     uint64_t audiounit_latency_us = audiounit_latency_sec * 1e6;
-    uint64_t device_latency_us    = ca_frames_to_us(ao, frames);
+    uint64_t device_latency_us    = ca_get_device_latency_us(ao, p->device);
 
     MP_VERBOSE(ao, "audiounit latency [us]: %lld\n", audiounit_latency_us);
     MP_VERBOSE(ao, "device latency [us]: %lld\n", device_latency_us);
diff --git a/audio/out/ao_coreaudio_exclusive.c b/audio/out/ao_coreaudio_exclusive.c
index 031bc67b9e..f8aba87188 100644
--- a/audio/out/ao_coreaudio_exclusive.c
+++ b/audio/out/ao_coreaudio_exclusive.c
@@ -320,24 +320,7 @@ static int init(struct ao *ao)
         goto coreaudio_error;
     }
 
-    uint32_t latency_frames = 0;
-    uint32_t latency_properties[] = {
-        kAudioDevicePropertyLatency,
-        kAudioDevicePropertyBufferFrameSize,
-        kAudioDevicePropertySafetyOffset,
-    };
-    for (int n = 0; n < MP_ARRAY_SIZE(latency_properties); n++) {
-        uint32_t temp;
-        err = CA_GET_O(p->device, latency_properties[n], &temp);
-        CHECK_CA_WARN("cannot get device latency");
-        if (err == noErr) {
-            latency_frames += temp;
-            MP_VERBOSE(ao, "Latency property %s: %d frames\n",
-                       fourcc_repr(latency_properties[n]), (int)temp);
-        }
-    }
-
-    p->hw_latency_us = ca_frames_to_us(ao, latency_frames);
+    p->hw_latency_us = ca_get_device_latency_us(ao, p->device);
     MP_VERBOSE(ao, "base latency: %d microseconds\n", (int)p->hw_latency_us);
 
     err = enable_property_listener(ao, true);
diff --git a/audio/out/ao_coreaudio_utils.c b/audio/out/ao_coreaudio_utils.c
index 2c3a5b4c50..f6463a314a 100644
--- a/audio/out/ao_coreaudio_utils.c
+++ b/audio/out/ao_coreaudio_utils.c
@@ -448,6 +448,28 @@ OSStatus ca_enable_mixing(struct ao *ao, AudioDeviceID device, bool changed)
     return noErr;
 }
 
+int64_t ca_get_device_latency_us(struct ao *ao, AudioDeviceID device)
+{
+    uint32_t latency_frames = 0;
+    uint32_t latency_properties[] = {
+        kAudioDevicePropertyLatency,
+        kAudioDevicePropertyBufferFrameSize,
+        kAudioDevicePropertySafetyOffset,
+    };
+    for (int n = 0; n < MP_ARRAY_SIZE(latency_properties); n++) {
+        uint32_t temp;
+        OSStatus err = CA_GET_O(device, latency_properties[n], &temp);
+        CHECK_CA_WARN("cannot get device latency");
+        if (err == noErr) {
+            latency_frames += temp;
+            MP_VERBOSE(ao, "Latency property %s: %d frames\n",
+                       fourcc_repr(latency_properties[n]), (int)temp);
+        }
+    }
+
+    return ca_frames_to_us(ao, latency_frames);
+}
+
 static OSStatus ca_change_format_listener(
     AudioObjectID object, uint32_t n_addresses,
     const AudioObjectPropertyAddress addresses[],
diff --git a/audio/out/ao_coreaudio_utils.h b/audio/out/ao_coreaudio_utils.h
index 477531e9f2..a0b5aa002c 100644
--- a/audio/out/ao_coreaudio_utils.h
+++ b/audio/out/ao_coreaudio_utils.h
@@ -74,6 +74,7 @@ OSStatus ca_lock_device(AudioDeviceID device, pid_t *pid);
 OSStatus ca_unlock_device(AudioDeviceID device, pid_t *pid);
 OSStatus ca_disable_mixing(struct ao *ao, AudioDeviceID device, bool *changed);
 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);
 
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