sync: fix delayed subtitles when burned-in

sync was delaying delivery of subtitles which caused burn-in late.

1 files changed, 14 insertions, 0 deletions

diff --git a/libhb/sync.c b/libhb/sync.c
index 23e96a964..9f95c3c53 100644
--- a/libhb/sync.c
+++ b/libhb/sync.c
@@ -801,6 +801,20 @@ static void OutputBuffer( sync_common_t * common )
             if (hb_list_count(stream->in_queue) > stream->min_len)
             {
                 buf = hb_list_item(stream->in_queue, 0);
+                if (stream->type == SYNC_TYPE_SUBTITLE)
+                {
+                    // Forward subtitles immediately instead of interleaving.
+                    //
+                    // Normally, we interleave output by PTS in order to
+                    // optimize sync recovery.  This results in queueing
+                    // stream data that may not get delivered to it's
+                    // respecitive output fifo until the next input data
+                    // is received for that stream.  This isn't a problem
+                    // for continuous streams like audio and video, but
+                    // it delays subtitles unacceptably.
+                    out_stream = stream;
+                    break;
+                }
                 if (buf->s.start < pts)
                 {
                     pts = buf->s.start;