From df60e122037a7eed9604a91c9bed5abe93d1e50c Mon Sep 17 00:00:00 2001
From: Edward Hervey <edward@centricular.com>
Date: Fri, 5 May 2017 18:25:43 +0200
Subject: [PATCH] adaptivedemux: Implement GST_SEEK_TYPE_END usage for live

When dealing with live streams, we can't rely on GstSegment calculation
since it uses the segment duration to calculate the absolute values.

But since we are dealing with live *and* we know the ranges, we can
compute the absolute seeking values using the range stop (i.e. "now")
as the END position.

Allows seeking back to "live" by using start_type:GST_SEEK_TYPE_END
and start:0

https://bugzilla.gnome.org/show_bug.cgi?id=782228
---
 gst-libs/gst/adaptivedemux/gstadaptivedemux.c | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/gst-libs/gst/adaptivedemux/gstadaptivedemux.c b/gst-libs/gst/adaptivedemux/gstadaptivedemux.c
index a5e517bfef..c3f4cd65e1 100644
--- a/gst-libs/gst/adaptivedemux/gstadaptivedemux.c
+++ b/gst-libs/gst/adaptivedemux/gstadaptivedemux.c
@@ -1502,6 +1502,7 @@ gst_adaptive_demux_handle_seek_event (GstAdaptiveDemux * demux, GstPad * pad,
 
   if (gst_adaptive_demux_is_live (demux)) {
     gint64 range_start, range_stop;
+    gboolean changed = FALSE;
     if (!gst_adaptive_demux_get_live_seek_range (demux, &range_start,
             &range_stop)) {
       GST_MANIFEST_UNLOCK (demux);
@@ -1510,6 +1511,18 @@ gst_adaptive_demux_handle_seek_event (GstAdaptiveDemux * demux, GstPad * pad,
       return FALSE;
     }
 
+    /* Handle relative positioning for live streams (relative to the range_stop) */
+    if (start_type == GST_SEEK_TYPE_END) {
+      start = range_stop + start;
+      start_type = GST_SEEK_TYPE_SET;
+      changed = TRUE;
+    }
+    if (stop_type == GST_SEEK_TYPE_END) {
+      stop = range_stop + stop;
+      stop_type = GST_SEEK_TYPE_SET;
+      changed = TRUE;
+    }
+
     if (!(flags & GST_SEEK_FLAG_ACCURATE)) {
       /* If the accurate flag is not set, we allow seeking before the start
        * to map to the start for live cases, since those can return a "moving
@@ -1523,6 +1536,7 @@ gst_adaptive_demux_handle_seek_event (GstAdaptiveDemux * demux, GstPad * pad,
         start = range_start;
         if (stop != GST_CLOCK_TIME_NONE)
           stop += dt;
+        changed = TRUE;
       }
     }
 
@@ -1533,6 +1547,14 @@ gst_adaptive_demux_handle_seek_event (GstAdaptiveDemux * demux, GstPad * pad,
       gst_event_unref (event);
       return FALSE;
     }
+
+    if (changed) {
+      gst_event_unref (event);
+      event =
+          gst_event_new_seek (rate, format, flags,
+          start_type, start, stop_type, stop);
+
+    }
   }
 
   seqnum = gst_event_get_seqnum (event);