coreaudio: add the AudioUnit latency to the device latency

Sanjukademani · Dec 2, 2022 · 88fd1e6 · 88fd1e6
1 parent 9793d06
commit 88fd1e6
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Showing 2 changed files with 32 additions and 2 deletions.
diff --git a/modules/audio_output/coreaudio_common.c b/modules/audio_output/coreaudio_common.c
@@ -140,8 +140,30 @@ static vlc_tick_t
 GetLatency(audio_output_t *p_aout)
 {
     struct aout_sys_common *p_sys = (struct aout_sys_common *) p_aout->sys;
-    return p_sys->get_latency != NULL ? p_sys->get_latency(p_aout)
-                                      : p_sys->i_dev_latency_ticks;
+
+    vlc_tick_t dev_latency_ticks =
+        p_sys->get_latency != NULL ? p_sys->get_latency(p_aout)
+                                   : p_sys->i_dev_latency_ticks;
+
+    /* Add the AudioUnit latency to the auhal/audiounit_ios latency */
+    if (p_sys->au != NULL)
+    {
+        Float64 unit_s;
+        if (AudioUnitGetProperty(p_sys->au, kAudioUnitProperty_Latency,
+                                 kAudioUnitScope_Global, 0, &unit_s,
+                                 &(UInt32) { sizeof(unit_s) }) != noErr)
+            unit_s = 0;
+        vlc_tick_t us = vlc_tick_from_sec(unit_s);
+        if (us != p_sys->au_latency_ticks)
+        {
+            msg_Dbg(p_aout, "Adding AudioUnit latency: %" PRId64 "us", us);
+            p_sys->au_latency_ticks = us;
+        }
+
+        dev_latency_ticks += us;
+    }
+
+    return dev_latency_ticks;
 }
 
 /* Called from render callbacks. No lock, wait, and IO here */
@@ -339,6 +361,8 @@ ca_Initialize(audio_output_t *p_aout, const audio_sample_format_t *fmt,
 {
     struct aout_sys_common *p_sys = (struct aout_sys_common *) p_aout->sys;
 
+    p_sys->au = NULL;
+    p_sys->au_latency_ticks = 0;
     p_sys->i_underrun_size = 0;
     p_sys->b_paused = false;
     p_sys->started = false;
@@ -725,6 +749,7 @@ au_Initialize(audio_output_t *p_aout, AudioUnit au, audio_sample_format_t *fmt,
               const AudioChannelLayout *outlayout, vlc_tick_t i_dev_latency_ticks,
               get_latency_cb get_latency, bool *warn_configuration)
 {
+    struct aout_sys_common *p_sys = (struct aout_sys_common *) p_aout->sys;
     int ret;
     AudioChannelLayout *inlayout_buf = NULL;
     const AudioChannelLayout *inlayout = NULL;
@@ -852,6 +877,7 @@ au_Initialize(audio_output_t *p_aout, AudioUnit au, audio_sample_format_t *fmt,
         AudioUnitUninitialize(au);
         return VLC_EGENERIC;
     }
+    p_sys->au = au;
 
     return VLC_SUCCESS;
 }

diff --git a/modules/audio_output/coreaudio_common.h b/modules/audio_output/coreaudio_common.h
@@ -51,6 +51,8 @@ struct aout_sys_common
 {
     /* The following is owned by common.c (initialized from ca_Open) */
 
+    AudioUnit au; /* Can be NULL (pass-through) */
+
     mach_timebase_info_data_t tinfo;
 
     size_t              i_underrun_size;
@@ -71,6 +73,8 @@ struct aout_sys_common
     size_t timing_report_last_written_bytes;
     /* Number of bytes to write before sending a timing report */
     size_t timing_report_delay_bytes;
+    /* Last AudioUnit Latency, for debug/log purpose */
+    vlc_tick_t au_latency_ticks;
 
     union lock
     {