From 523e98396fa05282ca8e9d98a48426edf72c0023 Mon Sep 17 00:00:00 2001
From: Vincent Penquerc'h <vincent.penquerch@collabora.co.uk>
Date: Fri, 5 May 2017 12:48:41 +0100
Subject: [PATCH] oggdemux: fix clipping more samples than exist in the first
 packet

This can happen in Opus (and maybe other codecs ?), and would cause
failure to play.

https://bugzilla.gnome.org/show_bug.cgi?id=782157
---
 ext/ogg/gstoggdemux.c  | 24 ++++++++++++++++++------
 ext/ogg/gstoggstream.c | 14 +++-----------
 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/ext/ogg/gstoggdemux.c b/ext/ogg/gstoggdemux.c
index 5307521fba..6825f89708 100644
--- a/ext/ogg/gstoggdemux.c
+++ b/ext/ogg/gstoggdemux.c
@@ -736,9 +736,15 @@ gst_ogg_demux_chain_peer (GstOggPad * pad, ogg_packet * packet,
           }
           if (pad->map.audio_clipping
               && pad->current_granule - duration < -pad->map.granule_offset) {
-            if (pad->current_granule >= -pad->map.granule_offset)
-              clip_start = -pad->map.granule_offset;
-            else
+            if (pad->current_granule >= -pad->map.granule_offset) {
+              guint64 already_removed =
+                  pad->current_granule >
+                  duration ? pad->current_granule - duration : 0;
+              clip_start =
+                  already_removed >
+                  -pad->map.granule_offset ? 0 : -pad->map.granule_offset -
+                  already_removed;
+            } else
               clip_start = pad->current_granule;
           }
         } else {
@@ -747,9 +753,15 @@ gst_ogg_demux_chain_peer (GstOggPad * pad, ogg_packet * packet,
 
           if (pad->map.audio_clipping
               && pad->current_granule - duration < -pad->map.granule_offset) {
-            if (pad->current_granule >= -pad->map.granule_offset)
-              clip_start = -pad->map.granule_offset;
-            else
+            if (pad->current_granule >= -pad->map.granule_offset) {
+              guint64 already_removed =
+                  pad->current_granule >
+                  duration ? pad->current_granule - duration : 0;
+              clip_start =
+                  already_removed >
+                  -pad->map.granule_offset ? 0 : -pad->map.granule_offset -
+                  already_removed;
+            } else
               clip_start = pad->current_granule;
           }
         }
diff --git a/ext/ogg/gstoggstream.c b/ext/ogg/gstoggstream.c
index 34df107be1..042f102d18 100644
--- a/ext/ogg/gstoggstream.c
+++ b/ext/ogg/gstoggstream.c
@@ -2030,21 +2030,13 @@ granulepos_to_granule_opus (GstOggStream * pad, gint64 granulepos)
   if (granulepos == -1)
     return -1;
 
-  /* We must reject some particular cases for the first granpos */
-
   if (pad->first_granpos < 0 || granulepos < pad->first_granpos)
     pad->first_granpos = granulepos;
 
-  if (pad->first_granpos == granulepos) {
-    if (granulepos < -pad->granule_offset) {
-      GST_ERROR ("Invalid Opus stream: first granulepos (%" G_GINT64_FORMAT
-          ") less than preskip (%" G_GINT64_FORMAT ")", granulepos,
-          -pad->granule_offset);
-      return -1;
-    }
-  }
+  if (granulepos < -pad->granule_offset)
+    return 0;
 
-  return granulepos;
+  return granulepos + pad->granule_offset;
 }
 
 static gint64