ao_alsa: implement device listing & selection

Unfortunately, ALSA is particularly bad with this, because mpv has to
add all sorts of magic crap to the device name to make things work. The
device selection overrides this, so explicitly selecting devices will
most likely break your audio. This has yet to be solved.

1 files changed, 27 insertions, 0 deletions

diff --git a/audio/out/ao_alsa.c b/audio/out/ao_alsa.c
index 52f410cf5e..1b0703cea6 100644
--- a/audio/out/ao_alsa.c
+++ b/audio/out/ao_alsa.c
@@ -365,6 +365,8 @@ static int init(struct ao *ao)
             device = talloc_asprintf(ao, "plug:%s", device);
         }
     }
+    if (ao->device)
+        device = ao->device;
     if (p->cfg_device && p->cfg_device[0])
         device = p->cfg_device;
 
@@ -731,6 +733,30 @@ alsa_error:
     return -1;
 }
 
+static void list_devs(const struct ao_driver *d, struct ao_device_list *list)
+{
+    void **hints;
+    if (snd_device_name_hint(-1, "pcm", &hints) < 0)
+        return;
+
+    for (int n = 0; hints[n]; n++) {
+        char *name = snd_device_name_get_hint(hints[n], "NAME");
+        char *desc = snd_device_name_get_hint(hints[n], "DESC");
+        char *io = snd_device_name_get_hint(hints[n], "IOID");
+        if (io && strcmp(io, "Output") != 0)
+            continue;
+        char desc2[1024];
+        snprintf(desc2, sizeof(desc2), "%s", desc ? desc : "");
+        for (int i = 0; desc2[i]; i++) {
+            if (desc2[i] == '\n')
+                desc2[i] = '/';
+        }
+        ao_device_list_add(list, d, &(struct ao_device_desc){name, desc2});
+    }
+
+    snd_device_name_free_hint(hints);
+}
+
 #define OPT_BASE_STRUCT struct priv
 
 const struct ao_driver audio_out_alsa = {
@@ -748,6 +774,7 @@ const struct ao_driver audio_out_alsa = {
     .drain     = drain,
     .wait      = audio_wait,
     .wakeup    = ao_wakeup_poll,
+    .list_devs = list_devs,
     .priv_size = sizeof(struct priv),
     .priv_defaults = &(const struct priv) {
         .cfg_block = 1,