From dda16ee1fbe681ad747210aaea7727a3378c9af2 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Wed, 21 Oct 2015 18:54:48 +0200
Subject: ao_coreaudio_exclusive: deal with devices return different channel
 count

If the device returns an unexpected number of channels instead of the
requested count on init, don't immediately error out. Instead, look if
there's a channel map with the given number of channels.

If there isn't, still error out, because we don't want to guess the
channel layout.
---
 audio/out/ao_coreaudio_chmap.c     | 25 +++++++++++++++++++++++++
 audio/out/ao_coreaudio_chmap.h     |  4 ++++
 audio/out/ao_coreaudio_exclusive.c |  5 ++++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/audio/out/ao_coreaudio_chmap.c b/audio/out/ao_coreaudio_chmap.c
index b1572dabd1..0405338828 100644
--- a/audio/out/ao_coreaudio_chmap.c
+++ b/audio/out/ao_coreaudio_chmap.c
@@ -265,3 +265,28 @@ coreaudio_error:
     talloc_free(ta_ctx);
     return false;
 }
+
+void ca_get_active_chmap(struct ao *ao, AudioDeviceID device, int channel_count,
+                         struct mp_chmap *out_map)
+{
+    void *ta_ctx = talloc_new(NULL);
+
+    // Apparently, we have to guess by looking back at the supported layouts,
+    // and I haven't found a property that retrieves the actual currently
+    // active channel layout.
+
+    AudioChannelLayout *ml = ca_query_layout(ao, device, ta_ctx);
+    if (ml && ca_layout_to_mp_chmap(ao, ml, out_map)) {
+        if (channel_count == out_map->num)
+            goto done;
+    }
+
+    AudioChannelLayout *sl = ca_query_stereo_layout(ao, device, ta_ctx);
+    if (sl && ca_layout_to_mp_chmap(ao, sl, out_map)) {
+        if (channel_count == out_map->num)
+            goto done;
+    }
+
+    out_map->num = 0;
+done: ;
+}
diff --git a/audio/out/ao_coreaudio_chmap.h b/audio/out/ao_coreaudio_chmap.h
index ce31975b6d..a67e1dc252 100644
--- a/audio/out/ao_coreaudio_chmap.h
+++ b/audio/out/ao_coreaudio_chmap.h
@@ -20,6 +20,10 @@
 
 #include <AudioToolbox/AudioToolbox.h>
 
+struct mp_chmap;
+
 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
diff --git a/audio/out/ao_coreaudio_exclusive.c b/audio/out/ao_coreaudio_exclusive.c
index f8aba87188..c998ee825c 100644
--- a/audio/out/ao_coreaudio_exclusive.c
+++ b/audio/out/ao_coreaudio_exclusive.c
@@ -315,7 +315,10 @@ static int init(struct ao *ao)
     ao->samplerate = p->stream_asbd.mSampleRate;
 
     if (ao->channels.num != p->stream_asbd.mChannelsPerFrame) {
-        // We really expect that ca_init_chmap() fixes the layout to the HW's.
+        ca_active_chmap(ao, p->device, p->stream_asbd.mChannelsPerFrame,
+                        &ao->channels);
+    }
+    if (!ao->channels.num) {
         MP_ERR(ao, "number of channels changed, and unknown channel layout!\n");
         goto coreaudio_error;
     }
-- 
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