ao_alsa: if possible, reorder device maps to std layouts

Channel maps reported by the device as SND_CHMAP_TYPE_VAR can be freely
reordered. We don't use this much (out of laziness), but in this case
it's a simple way to reduce necessary reordering (which would be an
extra libavresample invocation), and to make debug output more readable.

1 files changed, 2 insertions, 0 deletions

diff --git a/audio/out/ao_alsa.c b/audio/out/ao_alsa.c
index 316bdc0b3c..6ff39ffcb2 100644
--- a/audio/out/ao_alsa.c
+++ b/audio/out/ao_alsa.c
@@ -306,6 +306,8 @@ static bool query_chmaps(struct ao *ao, struct mp_chmap *chmap)
         mp_chmap_from_alsa(&entry, &maps[i]->map);
 
         if (mp_chmap_is_valid(&entry)) {
+            if (maps[i]->type == SND_CHMAP_TYPE_VAR)
+                mp_chmap_reorder_norm(&entry);
             MP_VERBOSE(ao, "Got supported channel map: %s (type %s)\n",
                        mp_chmap_to_str(&entry),
                        snd_pcm_chmap_type_name(maps[i]->type));