qtmux: remove subtraction that makes PTS/DTS start from 0

As qt uses durations, it doesn't matter, only the difference
between consecutive buffers is important. Also, collectpads
already replaces PTS/DTS with the running times for them.

1 files changed, 2 insertions, 38 deletions

diff --git a/gst/isomp4/gstqtmux.c b/gst/isomp4/gstqtmux.c
index a8054a178..898d38f04 100644
--- a/gst/isomp4/gstqtmux.c
+++ b/gst/isomp4/gstqtmux.c
@@ -2330,21 +2330,6 @@ init:
   return ret;
 }
 
-static void
-check_and_subtract_ts (GstQTMux * qtmux, GstClockTime * ts_a, GstClockTime ts_b)
-{
-  if (G_LIKELY (GST_CLOCK_TIME_IS_VALID (*ts_a))) {
-    if (G_LIKELY (*ts_a >= ts_b)) {
-      *ts_a -= ts_b;
-    } else {
-      *ts_a = 0;
-      GST_WARNING_OBJECT (qtmux, "Subtraction would result in negative value, "
-          "using 0 as result");
-    }
-  }
-}
-
-
 static GstFlowReturn
 gst_qt_mux_register_and_push_sample (GstQTMux * qtmux, GstQTPad * pad,
     GstBuffer * buffer, gboolean is_last_buffer, guint nsamples,
@@ -2408,13 +2393,6 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
     buf = pad->prepare_buf_func (pad, buf, qtmux);
   }
 
-  if (G_LIKELY (buf != NULL && GST_CLOCK_TIME_IS_VALID (pad->first_ts) &&
-          pad->first_ts != 0)) {
-    buf = gst_buffer_make_writable (buf);
-    check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (buf), pad->first_ts);
-    check_and_subtract_ts (qtmux, &GST_BUFFER_PTS (buf), pad->first_ts);
-  }
-
   last_buf = pad->last_buf;
 
   /* DTS delta is used to calculate sample duration.
@@ -2429,11 +2407,7 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
         GST_BUFFER_DURATION (last_buf) : 0;
 
     buf = gst_buffer_make_writable (buf);
-    GST_BUFFER_DTS (buf) =
-        gst_segment_to_running_time (&pad->collect.segment, GST_FORMAT_TIME,
-        pad->collect.segment.start);
-    if (GST_CLOCK_TIME_IS_VALID (pad->first_ts))
-      check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (buf), pad->first_ts);
+    GST_BUFFER_DTS (buf) = 0;   /* running-time 0 */
 
     if (last_buf
         && (GST_BUFFER_DTS (last_buf) + last_buf_duration) >
@@ -2471,7 +2445,6 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
   /* if this is the first buffer, store the timestamp */
   if (G_UNLIKELY (pad->first_ts == GST_CLOCK_TIME_NONE) && last_buf) {
     if (GST_BUFFER_DTS_IS_VALID (last_buf)) {
-      /* first pad always has DTS. If it was not provided by upstream it was set to segment start */
       pad->first_ts = GST_BUFFER_DTS (last_buf);
     } else if (GST_BUFFER_PTS_IS_VALID (last_buf)) {
       pad->first_ts = GST_BUFFER_PTS (last_buf);
@@ -2479,23 +2452,14 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
 
     if (GST_CLOCK_TIME_IS_VALID (pad->first_ts)) {
       GST_DEBUG ("setting first_ts to %" G_GUINT64_FORMAT, pad->first_ts);
-      last_buf = gst_buffer_make_writable (last_buf);
-      check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (last_buf), pad->first_ts);
-      check_and_subtract_ts (qtmux, &GST_BUFFER_PTS (last_buf), pad->first_ts);
-      if (buf) {
-        buf = gst_buffer_make_writable (buf);
-        check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (buf), pad->first_ts);
-        check_and_subtract_ts (qtmux, &GST_BUFFER_PTS (buf), pad->first_ts);
-      }
     } else {
-      GST_ERROR_OBJECT (qtmux, "First buffer for pad %s has no timestamp, "
+      GST_WARNING_OBJECT (qtmux, "First buffer for pad %s has no timestamp, "
           "using 0 as first timestamp", GST_PAD_NAME (pad->collect.pad));
       pad->first_ts = 0;
     }
     GST_DEBUG_OBJECT (qtmux, "Stored first timestamp for pad %s %"
         GST_TIME_FORMAT, GST_PAD_NAME (pad->collect.pad),
         GST_TIME_ARGS (pad->first_ts));
-
   }
 
   if (last_buf && buf && GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DTS (buf)) &&