subs: restore support for sub_step command with libass

This was destroyed by Uoti Urpala in commit "subs: always use sub...".
Features should be either kept working or completely removed, but not
just crippled, which only inflates the code and frustrates users.

1 files changed, 10 insertions, 0 deletions

diff --git a/sub/sd_ass.c b/sub/sd_ass.c
index 67bbd4665e..37c220a4b5 100644
--- a/sub/sd_ass.c
+++ b/sub/sd_ass.c
@@ -192,3 +192,13 @@ struct sh_sub *sd_ass_create_from_track(struct ass_track *track,
     };
     return sh;
 }
+
+struct ass_track *sub_get_ass_track(struct osd_state *osd)
+{
+    struct sh_sub *sh = osd ? osd->sh_sub : NULL;
+    if (sh && sh->sd_driver == &sd_ass && sh->context) {
+        struct sd_ass_priv *ctx = sh->context;
+        return ctx->ass_track;
+    }
+    return NULL;
+}