audio: change playback restart and resyncing

This commit makes audio decoding non-blocking. If e.g. the network is
too slow the playloop will just go to sleep, instead of blocking until
enough data is available.

For video, this was already done with commit 7083f88c. For audio, it's
unfortunately much more complicated, because the audio decoder was used
in a blocking manner. Large changes are required to get around this.
The whole playback restart mechanism must be turned into a statemachine,
especially since it has close interactions with video restart. Lots of
video code is thus also changed.

(For the record, I don't think switching this code to threads would
make this conceptually easier: the code would still have to deal with
external input while blocked, so these in-between states do get visible
[and thus need to be handled] anyway. On the other hand, it certainly
should be possible to modularize this code a bit better.)

This will probably cause a bunch of regressions.

1 files changed, 4 insertions, 3 deletions

diff --git a/audio/decode/dec_audio.h b/audio/decode/dec_audio.h
index f9269b5272..6d2c61d862 100644
--- a/audio/decode/dec_audio.h
+++ b/audio/decode/dec_audio.h
@@ -51,15 +51,16 @@ struct dec_audio {
 enum {
     AD_OK = 0,
     AD_ERR = -1,
-    AD_NEW_FMT = -2,
-    AD_ASYNC_PLAY_DONE = -3,
-    AD_EOF = -4,
+    AD_EOF = -2,
+    AD_NEW_FMT = -3,
+    AD_WAIT = -4,
 };
 
 struct mp_decoder_list *audio_decoder_list(void);
 int audio_init_best_codec(struct dec_audio *d_audio, char *audio_decoders);
 int audio_decode(struct dec_audio *d_audio, struct mp_audio_buffer *outbuf,
                  int minsamples);
+int initial_audio_decode(struct dec_audio *d_audio);
 void audio_reset_decoding(struct dec_audio *d_audio);
 void audio_uninit(struct dec_audio *d_audio);