From b517b59171790fd160f14f6ef85eb055e24873b2 Mon Sep 17 00:00:00 2001
From: Thibault Saunier <tsaunier@igalia.com>
Date: Tue, 28 Apr 2020 13:28:32 -0400
Subject: [PATCH] identity,clocksync: Fix timestamping inside single segment in
 reverse playback

In reverse playback, buffers are played back from buffer.stop
(buffer.pts + buffer.duration) to buffer.pts running times which
mean that we need to use the buffer end running time as a buffer
timestsamp, not the buffer pts when using a single segment in reverse
playback.

This is now being tested in
`validate.test.identity.reverse_single_segment`

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/450>
---
 plugins/elements/gstclocksync.c | 19 +++++++++++++++----
 plugins/elements/gstidentity.c  | 19 +++++++++++++++----
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/plugins/elements/gstclocksync.c b/plugins/elements/gstclocksync.c
index 7ca1a923fd..ede3277f44 100644
--- a/plugins/elements/gstclocksync.c
+++ b/plugins/elements/gstclocksync.c
@@ -338,10 +338,21 @@ gst_clock_sync_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
     GstClockTime runtimestamp = 0;
     GstClockTime rundts, runpts;
 
-    rundts = gst_segment_to_running_time (&clocksync->segment,
-        GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
-    runpts = gst_segment_to_running_time (&clocksync->segment,
-        GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
+    if (clocksync->segment.rate > 0.0) {
+      rundts = gst_segment_to_running_time (&clocksync->segment,
+          GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
+      runpts = gst_segment_to_running_time (&clocksync->segment,
+          GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
+    } else {
+      runpts = gst_segment_to_running_time (&clocksync->segment,
+          GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
+          && GST_CLOCK_TIME_IS_VALID (buf->pts) ? buf->pts +
+          buf->duration : buf->pts);
+      rundts = gst_segment_to_running_time (&clocksync->segment,
+          GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
+          && GST_CLOCK_TIME_IS_VALID (buf->dts) ? buf->dts +
+          buf->duration : buf->dts);
+    }
 
     if (GST_CLOCK_TIME_IS_VALID (rundts))
       runtimestamp = rundts;
diff --git a/plugins/elements/gstidentity.c b/plugins/elements/gstidentity.c
index a653428c9a..ffa0756a0e 100644
--- a/plugins/elements/gstidentity.c
+++ b/plugins/elements/gstidentity.c
@@ -687,10 +687,21 @@ gst_identity_transform_ip (GstBaseTransform * trans, GstBuffer * buf)
     g_signal_emit (identity, gst_identity_signals[SIGNAL_HANDOFF], 0, buf);
 
   if (trans->segment.format == GST_FORMAT_TIME) {
-    rundts = gst_segment_to_running_time (&trans->segment,
-        GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
-    runpts = gst_segment_to_running_time (&trans->segment,
-        GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
+    if (trans->segment.rate > 0) {
+      runpts = gst_segment_to_running_time (&trans->segment,
+          GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
+      rundts = gst_segment_to_running_time (&trans->segment,
+          GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
+    } else {
+      runpts = gst_segment_to_running_time (&trans->segment,
+          GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
+          && GST_CLOCK_TIME_IS_VALID (buf->pts) ? buf->pts +
+          buf->duration : buf->pts);
+      rundts = gst_segment_to_running_time (&trans->segment,
+          GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
+          && GST_CLOCK_TIME_IS_VALID (buf->dts) ? buf->dts +
+          buf->duration : buf->dts);
+    }
   }
 
   if (GST_CLOCK_TIME_IS_VALID (rundts))