libhb: fix blinking of rendered closed captions

Rounding errors in timestamps caused single frame duration gaps


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6454 b64f7644-9d1e-0410-96f1-a4d463321fa5

1 files changed, 16 insertions, 5 deletions

diff --git a/libhb/rendersub.c b/libhb/rendersub.c
index 4d085bd9b..1ca7ac7bc 100644
--- a/libhb/rendersub.c
+++ b/libhb/rendersub.c
@@ -623,8 +623,8 @@ static void process_sub(hb_filter_private_t *pv, hb_buffer_t *sub)
     // Parse MKV-SSA packet
     // SSA subtitles always have an explicit stop time, so we
     // do not need to do special processing for stop == AV_NOPTS_VALUE
-    start = sub->s.start / 90;
-    dur = (sub->s.stop - sub->s.start) / 90;
+    start = sub->s.start;
+    dur = sub->s.stop - sub->s.start;
     ass_process_chunk(pv->ssaTrack, ssa, sub->size, start, dur);
     free(ssa);
 }
@@ -652,10 +652,20 @@ static int textsub_work(hb_filter_object_t * filter,
         return HB_FILTER_DONE;
     }
 
+    int in_start_ms = in->s.start / 90;
+
     // Get any pending subtitles and add them to the active
     // subtitle list
     while ((sub = hb_fifo_get(filter->subtitle->fifo_out)))
     {
+        // libass expects times in ms.  So to make the math easy,
+        // convert to ms immediately.
+        sub->s.start /= 90;
+        if (sub->s.stop != AV_NOPTS_VALUE)
+        {
+            sub->s.stop /= 90;
+        }
+
         // Subtitle formats such as CC can have stop times
         // that are not known until an "erase display" command
         // is encountered in the stream.  For these formats
@@ -681,6 +691,7 @@ static int textsub_work(hb_filter_object_t * filter,
             // We don't know the duration of this sub.  So we will
             // apply it to every video frame until we see a "clear" sub.
             pv->current_sub = sub;
+            pv->current_sub->s.stop = pv->current_sub->s.start;
         }
         else
         {
@@ -690,13 +701,13 @@ static int textsub_work(hb_filter_object_t * filter,
             hb_buffer_close(&sub);
         }
     }
-    if (pv->current_sub != NULL && pv->current_sub->s.start <= in->s.start)
+    if (pv->current_sub != NULL && pv->current_sub->s.start <= in_start_ms)
     {
         // We don't know the duration of this subtitle, but we know
         // that it started before the current video frame and that
         // it is still active.  So render it on this video frame.
-        pv->current_sub->s.start = in->s.start;
-        pv->current_sub->s.stop = in->s.start + 90;
+        pv->current_sub->s.start = pv->current_sub->s.stop;
+        pv->current_sub->s.stop = in_start_ms + 1;
         process_sub(pv, pv->current_sub);
     }