From b8b2946e03305cc60ac17b7df9437aad58c22a03 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 22 Mar 2017 12:04:35 +0200
Subject: [PATCH] dashdemux: In reverse playback mode, if seeking to the
 beginning of a fragment, start with the previous one instead

There's no point to start downloading a fragment just to output 1ns.
---
 ext/dash/gstdashdemux.c | 4 ++++
 ext/dash/gstmpdparser.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/ext/dash/gstdashdemux.c b/ext/dash/gstdashdemux.c
index 461ec7fab2..0af18c2bb1 100644
--- a/ext/dash/gstdashdemux.c
+++ b/ext/dash/gstdashdemux.c
@@ -1290,6 +1290,10 @@ gst_dash_demux_stream_sidx_seek (GstDashDemuxStream * dashstream,
 
   /* FIXME in reverse mode, if we are exactly at a fragment start it makes more
    * sense to start from the end of the previous fragment */
+  if (!forward && idx > 0 && entry->pts == ts) {
+    idx--;
+    entry = &sidx->entries[idx];
+  }
 
   /* Now entry->pts <= ts < entry->pts + entry->duration, need to adjust for
    * snapping */
diff --git a/ext/dash/gstmpdparser.c b/ext/dash/gstmpdparser.c
index a1d4cdace1..9443701913 100644
--- a/ext/dash/gstmpdparser.c
+++ b/ext/dash/gstmpdparser.c
@@ -4864,6 +4864,11 @@ gst_mpd_client_stream_seek (GstMpdClient * client, GstActiveStream * stream,
       ts = 0;
 
     index = ts / duration;
+
+    /* At the end of a segment in reverse mode, start from the previous fragment */
+    if (!forward && index > 0 && ts % duration == 0)
+      index--;
+
     index_time = index * duration;
 
     if ((flags & GST_SEEK_FLAG_SNAP_NEAREST) == GST_SEEK_FLAG_SNAP_NEAREST) {