audio: add --audio-spdif as new method for enabling passthrough

This provides a new method for enabling spdif passthrough. The old
method via --ad (--ad=spdif:ac3 etc.) is deprecated. The deprecated
method will probably stop working at some point.

This also supports PCM fallback. One caveat is that it will lose at
least 1 audio packet in doing so. (I don't care enough to prevent this.)

(This is named after the old S/PDIF connector, because it uses the same
underlying technology as far as the higher level protoco is concerned.
Also, the user should be renamed that passthrough is backwards.)

2 files changed, 18 insertions, 1 deletions

diff --git a/player/audio.c b/player/audio.c
index 559e194218..b354f701ae 100644
--- a/player/audio.c
+++ b/player/audio.c
@@ -190,8 +190,9 @@ void reinit_audio_chain(struct MPContext *mpctx)
         mpctx->d_audio->pool = mp_audio_pool_create(mpctx->d_audio);
         mpctx->d_audio->afilter = af_new(mpctx->global);
         mpctx->d_audio->afilter->replaygain_data = sh->audio->replaygain_data;
+        mpctx->d_audio->spdif_passthrough = true;
         mpctx->ao_buffer = mp_audio_buffer_create(NULL);
-        if (!audio_init_best_codec(mpctx->d_audio, opts->audio_decoders))
+        if (!audio_init_best_codec(mpctx->d_audio))
             goto init_error;
         reset_audio_state(mpctx);
 
@@ -264,6 +265,18 @@ void reinit_audio_chain(struct MPContext *mpctx)
         }
 
         if (!mpctx->ao) {
+            // If spdif was used, try to fallback to PCM.
+            if (AF_FORMAT_IS_SPECIAL(afs->output.format) &&
+                mpctx->d_audio->spdif_passthrough)
+            {
+                mpctx->d_audio->spdif_passthrough = false;
+                if (!audio_init_best_codec(mpctx->d_audio))
+                    goto init_error;
+                reset_audio_state(mpctx);
+                reinit_audio_chain(mpctx);
+                return;
+            }
+
             MP_ERR(mpctx, "Could not open/initialize audio device -> no sound.\n");
             mpctx->error_playing = MPV_ERROR_AO_INIT_FAILED;
             goto init_error;
diff --git a/player/main.c b/player/main.c
index bb22069bfc..06b1867ebe 100644
--- a/player/main.c
+++ b/player/main.c
@@ -278,6 +278,10 @@ static bool handle_help_options(struct MPContext *mpctx)
         talloc_free(list);
         opt_exit = 1;
     }
+    if (opts->audio_spdif && strcmp(opts->audio_spdif, "help") == 0) {
+        MP_INFO(mpctx, "Choices: ac3,dts-hd,dts (and possibly more)\n");
+        opt_exit = 1;
+    }
     if (opts->video_decoders && strcmp(opts->video_decoders, "help") == 0) {
         struct mp_decoder_list *list = video_decoder_list();
         mp_print_decoders(log, MSGL_INFO, "Video decoders:", list);