sub: add sd_spu.c to wrap spudec, cleanup mplayer.c

This unifies the subtitle rendering path. Now all subtitle rendering
goes through sd_ass.c/sd_lavc.c/sd_spu.c.

Before that commit, the spudec.h functions were used directly in
mplayer.c, which introduced many special cases. Add sd_spu.c, which is
just a small wrapper connecting the new subtitle render API with the
dusty old vobsub decoder in spudec.c.

One detail that changes is that we always pass the palette as extra
data, instead of passing the libdvdread palette as pointer to spudec
directly. This is a bit roundabout, but actually makes the code simpler
and more elegant: the difference between DVD and non-DVD dvdsubs is
reduced.

Ideally, we would just delete spudec.c and use libavcodec's DVD sub
decoder. However, DVD playback with demux_mpg produces packets
incompatible to lavc. There are incompatibilities the other way around
as well: packets from libavformat's vobsub demuxer are incompatible to
spudec.c. So we define a new subtitle codec name for demux_mpg subs,
"dvd_subtitle_mpg", which only sd_spu can decode.

There is actually code in spudec.c to "assemble" fragments into complete
packets, but using the whole spudec.c is easier than trying to move this
code into demux_mpg to fix subtitle packets.

As additional complication, Libav 9.x can't decode DVD subs correctly,
so use sd_spu in that case as well.

1 files changed, 19 insertions, 9 deletions

diff --git a/sub/dec_sub.c b/sub/dec_sub.c
index 3de7d1223d..36ba25edd2 100644
--- a/sub/dec_sub.c
+++ b/sub/dec_sub.c
@@ -29,6 +29,16 @@
 
 extern const struct sd_functions sd_ass;
 extern const struct sd_functions sd_lavc;
+extern const struct sd_functions sd_spu;
+
+static const struct sd_functions *sd_list[] = {
+#ifdef CONFIG_ASS
+    &sd_ass,
+#endif
+    &sd_lavc,
+    &sd_spu,
+    NULL
+};
 
 bool is_text_sub(const char *t)
 {
@@ -46,20 +56,20 @@ bool is_ass_sub(const char *t)
 
 bool is_dvd_sub(const char *t)
 {
-    return t && strcmp(t, "dvd_subtitle") == 0;
+    return t && (strcmp(t, "dvd_subtitle") == 0 ||
+                 strcmp(t, "dvd_subtitle_mpg") == 0);
 }
 
 void sub_init(struct sh_sub *sh, struct osd_state *osd)
 {
-    const char *format = sh->gsh->codec;
+    sh->sd_driver = NULL;
+    for (int n = 0; sd_list[n]; n++) {
+        if (sd_list[n]->supports_format(sh->gsh->codec)) {
+            sh->sd_driver = sd_list[n];
+            break;
+        }
+    }
 
-    assert(!osd->sh_sub);
-    if (sd_lavc.supports_format(format))
-        sh->sd_driver = &sd_lavc;
-#ifdef CONFIG_ASS
-    if (sd_ass.supports_format(format))
-        sh->sd_driver = &sd_ass;
-#endif
     if (sh->sd_driver) {
         if (sh->sd_driver->init(sh, osd) < 0)
             return;