From c2de6fdf345b72a0f69f9b4b9618599a7287c2c8 Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <stefano.pigozzi@gmail.com>
Date: Mon, 8 Jul 2013 22:58:01 +0200
Subject: ao_coreaudio: set channel layout based on hardware query

this is a wip
---
 audio/out/ao_coreaudio.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 106 insertions(+), 2 deletions(-)

(limited to 'audio')

diff --git a/audio/out/ao_coreaudio.c b/audio/out/ao_coreaudio.c
index 65e51bce7d..6c1cdb9150 100644
--- a/audio/out/ao_coreaudio.c
+++ b/audio/out/ao_coreaudio.c
@@ -313,11 +313,115 @@ static int init(struct ao *ao, char *params)
     }
 
     if (!supports_digital) {
+        uint32_t size;
+        AudioObjectPropertyAddress p_addr = (AudioObjectPropertyAddress) {
+            .mSelector = kAudioDevicePropertyPreferredChannelLayout,
+            .mScope    = kAudioDevicePropertyScopeOutput,
+            .mElement  = kAudioObjectPropertyElementMaster,
+        };
+
+        err = AudioObjectGetPropertyDataSize(selected_device, &p_addr, 0, NULL,
+                                             &size);
+        CHECK_CA_ERROR("could not get audio device prefered layouts size");
+        size_t n_layouts = size / sizeof(AudioChannelLayout);
+
+        AudioChannelLayout *layouts = (AudioChannelLayout *) malloc(size);
+        err = AudioObjectGetPropertyData(selected_device, &p_addr, 0, NULL,
+                                         &size, layouts);
+        CHECK_CA_ERROR("could not get audio device prefered layouts");
+
+        uint32_t bitmaps[n_layouts];
+        size_t   n_bitmaps = 0;
+
+        for (int i=0; i < n_layouts; i++) {
+            ca_msg(MSGL_WARN, "channel layout %d:\n", i);
+
+            switch (layouts[i].mChannelLayoutTag) {
+            case kAudioChannelLayoutTag_UseChannelBitmap:
+                // This is the best case. CoreAudio's representation of the
+                // layout is the same of what mpv uses internally.
+                ca_msg(MSGL_WARN, "channel layout !\n");
+                bitmaps[n_bitmaps++] = layouts[i].mChannelBitmap;
+            case kAudioChannelLayoutTag_UseChannelDescriptions: {
+                // If the channel layout uses channel descriptions, from my
+                // exepriments there are there three possibile cases:
+                // * The description has a label kAudioChannelLabel_Unknown:
+                //   Can't do anything about this (looks like non surround
+                //   layouts are like this).
+                // * The description uses positional information: this in
+                //   theory could be used but one would have to map spatial
+                //   positions to labels which is not really feasible.
+                // * The description has a well known label which can be mapped
+                //   to the waveextensible definition: this is the kind of
+                //   descriptions we process here.
+                ca_msg(MSGL_WARN, "descriptions!\n");
+                size_t ch_num = layouts[i].mNumberChannelDescriptions;
+
+                uint32_t bitmap = 0;
+                bool all_channels_valid = true;
+
+                for (int j=0; j < ch_num && all_channels_valid; j++) {
+                    AudioChannelLabel label =
+                        layouts[i].mChannelDescriptions[j].mChannelLabel;
+
+                    if (label == kAudioChannelLabel_UseCoordinates ||
+                        label == kAudioChannelLabel_Unknown ||
+                        label > kAudioChannelLabel_TopBackRight) {
+                        ca_msg(MSGL_WARN,
+                                "channel label=%d unusable to build channel "
+                                "bitmap, skipping layout\n", label);
+                        all_channels_valid = false;
+                    } else {
+                        bitmap |= 1ULL << (label - 1);
+                    }
+                }
+
+                if (all_channels_valid)
+                    bitmaps[n_bitmaps++] = bitmap;
+
+                break;
+            }
+            default: {
+                ca_msg(MSGL_WARN, "some tag!\n");
+                // This layout is defined exclusively by it's tag. Use the Audio
+                // Format Services API to try and convert it to a bitmap that
+                // mpv can use.
+                uint32_t bitmap;
+                uint32_t bitmap_size = sizeof(uint32_t);
+                AudioChannelLayoutTag tag = layouts[i].mChannelLayoutTag;
+                err = AudioFormatGetProperty(
+                    kAudioFormatProperty_BitmapForLayoutTag,
+                    sizeof(AudioChannelLayoutTag), &tag,
+                    &bitmap_size, &bitmap);
+                if (err != noErr) {
+                    ca_msg(MSGL_WARN,
+                            "channel layout tag=%d unusable to build channel "
+                            "bitmap, skipping layout\n", tag);
+                } else {
+                    bitmaps[n_bitmaps++] = bitmap;
+                }
+            }
+            }
+        } // closes for
+
         struct mp_chmap_sel chmap_sel = {0};
-        mp_chmap_sel_add_waveext(&chmap_sel);
+
+        for (int i=0; i < n_bitmaps; i++) {
+            struct mp_chmap chmap = {0};
+            mp_chmap_from_lavc(&chmap, bitmaps[i]);
+            mp_chmap_sel_add_map(&chmap_sel, &chmap);
+        }
+
+        if (n_bitmaps < 1)
+            // Could not get from the hardware any usable bitmap, default to
+            // waveext...
+            mp_chmap_sel_add_waveext(&chmap_sel);
+
         if (!ao_chmap_sel_adjust(ao, &chmap_sel, &ao->channels))
             goto coreaudio_error;
-    }
+
+        free(layouts);
+    } // closes if (!supports_digital)
 
     // Build ASBD for the input format
     AudioStreamBasicDescription asbd;
-- 
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