diff --git a/ChangeLog b/ChangeLog
index 38979e5b1a..65ba81c4db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2006-05-23  Tim-Philipp Müller  <tim at centricular dot net>
+
+	* ext/theora/theoradec.c: (theora_dec_chain):
+	  Make work with time-stamped input buffers that do not
+	  have a granulepos in BUFFER_OFFSET_END (like theora
+	  buffers coming from matroskademux). Fixes #342448.
+
 2006-05-22  Tim-Philipp Müller  <tim at centricular dot net>
 
 	Patch by: Peter Kjellerstedt  <pkj at axis com>
diff --git a/ext/theora/theoradec.c b/ext/theora/theoradec.c
index 77ba63ce23..f813aef9b2 100644
--- a/ext/theora/theoradec.c
+++ b/ext/theora/theoradec.c
@@ -1134,6 +1134,8 @@ theora_dec_chain (GstPad * pad, GstBuffer * buf)
     } else if (dec->last_timestamp != -1) {
       dec->last_timestamp = _theora_granule_time (dec, dec->granulepos);
     }
+    if (dec->last_timestamp == -1 && GST_BUFFER_TIMESTAMP_IS_VALID (buf))
+      dec->last_timestamp = GST_BUFFER_TIMESTAMP (buf);
   } else {
     dec->last_timestamp = -1;
   }