From 81446d90715c8a6bc47cd090d0c0a104149e656c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 20 Apr 2016 11:46:19 +0300
Subject: [PATCH] baseparse: Remember if we interpolated DTS from PTS and
 refresh it whenever we update the PTS

Otherwise PTS and DTS will come out of sync if upstream continues to provide
PTS and not DTS, and we have to skip some data from the stream or PTS are not
exactly increasing with the duration of each packet.

https://bugzilla.gnome.org/show_bug.cgi?id=765260
---
 libs/gst/base/gstbaseparse.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/libs/gst/base/gstbaseparse.c b/libs/gst/base/gstbaseparse.c
index a5c3a2943c..50499a4b14 100644
--- a/libs/gst/base/gstbaseparse.c
+++ b/libs/gst/base/gstbaseparse.c
@@ -273,6 +273,7 @@ struct _GstBaseParsePrivate
   GstClockTime next_dts;
   GstClockTime prev_pts;
   GstClockTime prev_dts;
+  gboolean prev_dts_from_pts;
   GstClockTime frame_duration;
   gboolean seen_keyframe;
   gboolean is_video;
@@ -1308,6 +1309,7 @@ gst_base_parse_sink_event_default (GstBaseParse * parse, GstEvent * event)
       parse->priv->last_dts = GST_CLOCK_TIME_NONE;
       parse->priv->prev_pts = GST_CLOCK_TIME_NONE;
       parse->priv->prev_dts = GST_CLOCK_TIME_NONE;
+      parse->priv->prev_dts_from_pts = FALSE;
       parse->priv->discont = TRUE;
       parse->priv->seen_keyframe = FALSE;
       parse->priv->skip = 0;
@@ -2772,6 +2774,7 @@ gst_base_parse_start_fragment (GstBaseParse * parse)
   parse->priv->prev_pts = GST_CLOCK_TIME_NONE;
   parse->priv->next_dts = GST_CLOCK_TIME_NONE;
   parse->priv->prev_dts = GST_CLOCK_TIME_NONE;
+  parse->priv->prev_dts_from_pts = FALSE;
   /* prevent it hanging around stop all the time */
   parse->segment.position = GST_CLOCK_TIME_NONE;
   /* mark next run */
@@ -3142,6 +3145,7 @@ gst_base_parse_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
   /* Stop either when adapter is empty or we are flushing */
   while (!parse->priv->flushing) {
     gint flush = 0;
+    gboolean updated_prev_pts = FALSE;
 
     /* note: if subclass indicates MAX fsize,
      * this will not likely be available anyway ... */
@@ -3166,11 +3170,15 @@ gst_base_parse_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
      * but interpolate in between */
     pts = gst_adapter_prev_pts (parse->priv->adapter, NULL);
     dts = gst_adapter_prev_dts (parse->priv->adapter, NULL);
-    if (GST_CLOCK_TIME_IS_VALID (pts) && (parse->priv->prev_pts != pts))
+    if (GST_CLOCK_TIME_IS_VALID (pts) && (parse->priv->prev_pts != pts)) {
       parse->priv->prev_pts = parse->priv->next_pts = pts;
+      updated_prev_pts = TRUE;
+    }
 
-    if (GST_CLOCK_TIME_IS_VALID (dts) && (parse->priv->prev_dts != dts))
+    if (GST_CLOCK_TIME_IS_VALID (dts) && (parse->priv->prev_dts != dts)) {
       parse->priv->prev_dts = parse->priv->next_dts = dts;
+      parse->priv->prev_dts_from_pts = FALSE;
+    }
 
     /* we can mess with, erm interpolate, timestamps,
      * and incoming stuff has PTS but no DTS seen so far,
@@ -3178,9 +3186,12 @@ gst_base_parse_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
     if (parse->priv->infer_ts &&
         parse->priv->pts_interpolate &&
         !GST_CLOCK_TIME_IS_VALID (dts) &&
-        !GST_CLOCK_TIME_IS_VALID (parse->priv->prev_dts) &&
-        GST_CLOCK_TIME_IS_VALID (pts))
+        (!GST_CLOCK_TIME_IS_VALID (parse->priv->prev_dts)
+            || (parse->priv->prev_dts_from_pts && updated_prev_pts))
+        && GST_CLOCK_TIME_IS_VALID (pts)) {
       parse->priv->prev_dts = parse->priv->next_dts = pts;
+      parse->priv->prev_dts_from_pts = TRUE;
+    }
 
     /* always pass all available data */
     tmpbuf = gst_adapter_get_buffer (parse->priv->adapter, av);
@@ -4847,8 +4858,10 @@ gst_base_parse_set_ts_at_offset (GstBaseParse * parse, gsize offset)
   if (GST_CLOCK_TIME_IS_VALID (pts) && (parse->priv->prev_pts != pts))
     parse->priv->prev_pts = parse->priv->next_pts = pts;
 
-  if (GST_CLOCK_TIME_IS_VALID (dts) && (parse->priv->prev_dts != dts))
+  if (GST_CLOCK_TIME_IS_VALID (dts) && (parse->priv->prev_dts != dts)) {
     parse->priv->prev_dts = parse->priv->next_dts = dts;
+    parse->priv->prev_dts_from_pts = FALSE;
+  }
 }
 
 /**