From e12607348918a59dcc42757a3ec293f413b70d54 Mon Sep 17 00:00:00 2001
From: Vincent Penquerc'h <vincent.penquerch@collabora.co.uk>
Date: Wed, 6 Jun 2012 17:42:36 +0100
Subject: [PATCH] oggdemux: reject opus streams with negative start time

This is used by Vorbis for sample accurate clipping, but this is
deemed an invalid stream by the opus spec.
---
 ext/ogg/gstoggdemux.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/ext/ogg/gstoggdemux.c b/ext/ogg/gstoggdemux.c
index 5f10263f22..031c25d860 100644
--- a/ext/ogg/gstoggdemux.c
+++ b/ext/ogg/gstoggdemux.c
@@ -922,10 +922,16 @@ gst_ogg_pad_submit_packet (GstOggPad * pad, ogg_packet * packet)
           return GST_FLOW_ERROR;
         }
 
-        if (granule > pad->map.accumulated_granule)
+        if (granule >= pad->map.accumulated_granule)
           start_granule = granule - pad->map.accumulated_granule;
-        else
-          start_granule = 0;
+        else {
+          if (pad->map.forbid_start_clamping) {
+            GST_ERROR_OBJECT (ogg, "Start of stream maps to negative time");
+            return GST_FLOW_ERROR;
+          } else {
+            start_granule = 0;
+          }
+        }
 
         pad->start_time = gst_ogg_stream_granule_to_time (&pad->map,
             start_granule);