lua: add playback-start event

player/command.c

@@ -3223,6 +3223,7 @@ void mp_flush_events(struct MPContext *mpctx)
             switch (event) {
             case MP_EVENT_TICK:             name = "tick"; break;
             case MP_EVENT_TRACKS_CHANGED:   name = "track-layout"; break;
+            case MP_EVENT_PLAYBACK_START:   name = "playback-start"; break;
             case MP_EVENT_START_FILE:       name = "start"; break;
             case MP_EVENT_END_FILE:         name = "end"; break;
             default: ;

player/command.h

@@ -40,6 +40,7 @@ enum mp_event {
     MP_EVENT_PROPERTY,          // char*, property that is changed
     MP_EVENT_TRACKS_CHANGED,
     MP_EVENT_START_FILE,
+    MP_EVENT_PLAYBACK_START,
     MP_EVENT_END_FILE,
 };
 

player/loadfile.c

@@ -1332,6 +1332,8 @@ goto_reopen_demuxer: ;
     if (mpctx->opts->pause)
         pause_player(mpctx);
 
+    mp_notify(mpctx, MP_EVENT_PLAYBACK_START, NULL);
+
     playback_start = mp_time_sec();
     mpctx->error_playing = false;
     while (!mpctx->stop_play)