player: ensure backward playback state is propagated on track switching

Track switching doesn't run reset_playback_state(), so a track enabled
at runtime during backward playback would lead to a messed up state.

This commit just does a bad code monkey fix to this. It feels like there
needs to be a much better way to propagate this state.

4 files changed, 14 insertions, 5 deletions

diff --git a/player/audio.c b/player/audio.c
index d56b97c5ba..881d74a904 100644
--- a/player/audio.c
+++ b/player/audio.c
@@ -187,8 +187,12 @@ static void ao_chain_reset_state(struct ao_chain *ao_c)
 
 void reset_audio_state(struct MPContext *mpctx)
 {
-    if (mpctx->ao_chain)
+    if (mpctx->ao_chain) {
         ao_chain_reset_state(mpctx->ao_chain);
+        struct track *t = mpctx->ao_chain->track;
+        if (t && t->dec)
+            t->dec->play_dir = mpctx->play_dir;
+    }
     mpctx->audio_status = mpctx->ao_chain ? STATUS_SYNCING : STATUS_EOF;
     mpctx->delay = 0;
     mpctx->audio_drop_throttle = 0;
diff --git a/player/playloop.c b/player/playloop.c
index c415e5a90d..7ff82347bd 100644
--- a/player/playloop.c
+++ b/player/playloop.c
@@ -226,10 +226,9 @@ void reset_playback_state(struct MPContext *mpctx)
 
     for (int n = 0; n < mpctx->num_tracks; n++) {
         struct track *t = mpctx->tracks[n];
+        // (Often, but not always, this is redundant and also done elsewhere.)
         if (t->dec)
             t->dec->play_dir = mpctx->play_dir;
-        if (t->d_sub)
-            sub_set_play_dir(t->d_sub, mpctx->play_dir);
     }
 
     mpctx->hrseek_active = false;
diff --git a/player/sub.c b/player/sub.c
index 40e7aba30f..12a9696227 100644
--- a/player/sub.c
+++ b/player/sub.c
@@ -48,8 +48,10 @@ static int get_order(struct MPContext *mpctx, struct track *track)
 
 static void reset_subtitles(struct MPContext *mpctx, struct track *track)
 {
-    if (track->d_sub)
+    if (track->d_sub) {
         sub_reset(track->d_sub);
+        sub_set_play_dir(track->d_sub, mpctx->play_dir);
+    }
     term_osd_set_subs(mpctx, NULL);
 }
 
diff --git a/player/video.c b/player/video.c
index dd48e0a529..58115081d1 100644
--- a/player/video.c
+++ b/player/video.c
@@ -95,8 +95,12 @@ static void vo_chain_reset_state(struct vo_chain *vo_c)
 
 void reset_video_state(struct MPContext *mpctx)
 {
-    if (mpctx->vo_chain)
+    if (mpctx->vo_chain) {
         vo_chain_reset_state(mpctx->vo_chain);
+        struct track *t = mpctx->vo_chain->track;
+        if (t && t->dec)
+            t->dec->play_dir = mpctx->play_dir;
+    }
 
     for (int n = 0; n < mpctx->num_next_frames; n++)
         mp_image_unrefp(&mpctx->next_frames[n]);