sub: remove vobsub reader in favor of ffmpeg vobsub demuxer

ffmpeg recently added a demuxer that can read vobsubs (pairs of .sub and
.idx files). Get rid of the internal vobsub reader, and use the ffmpeg
demuxer instead.

Sneak in an unrelated manpage change (autosub default).

1 files changed, 10 insertions, 0 deletions

diff --git a/demux/demux.c b/demux/demux.c
index f765b2ae87..41b74b20c4 100644
--- a/demux/demux.c
+++ b/demux/demux.c
@@ -459,6 +459,16 @@ void free_demuxer(demuxer_t *demuxer)
 
 void ds_add_packet(demux_stream_t *ds, demux_packet_t *dp)
 {
+    // demux API can't handle 0-sized packets, but at least some vobsubs
+    // generate them. Skipping them seems to work fine. Not skipping them will
+    // stop demuxing with external vobsubs. See FATE sub/vobsub.{idx,sub} at
+    // pts=185.91.
+    if (dp->len == 0 && ds->stream_type == STREAM_SUB) {
+        mp_dbg(MSGT_DEMUXER, MSGL_INFO, "Discarding empty subtitle packet.\n");
+        free_demux_packet(dp);
+        return;
+    }
+
     // append packet to DS stream:
     ++ds->packs;
     ds->bytes += dp->len;