diff --git a/libmpdemux/demuxer.c b/libmpdemux/demuxer.c
index 7f95bf8f8f..1fa819ffa4 100644
--- a/libmpdemux/demuxer.c
+++ b/libmpdemux/demuxer.c
@@ -67,6 +67,12 @@ demuxer_t* new_demuxer(stream_t *stream,int type,int a_id,int v_id,int s_id){
 }
 
 sh_audio_t* new_sh_audio(demuxer_t *demuxer,int id){
+    if(id > MAX_A_STREAMS-1)
+    {
+	mp_msg(MSGT_DEMUXER,MSGL_WARN,"Requested audio stream id overflow (%d > %d)\n",
+	    id, MAX_A_STREAMS);
+	return NULL;
+    }
     if(demuxer->a_streams[id]){
         mp_msg(MSGT_DEMUXER,MSGL_WARN,MSGTR_AudioStreamRedefined,id);
     } else {
@@ -85,6 +91,12 @@ void free_sh_audio(sh_audio_t* sh){
 }
 
 sh_video_t* new_sh_video(demuxer_t *demuxer,int id){
+    if(id > MAX_V_STREAMS-1)
+    {
+	mp_msg(MSGT_DEMUXER,MSGL_WARN,"Requested video stream id overflow (%d > %d)\n",
+	    id, MAX_V_STREAMS);
+	return NULL;
+    }
     if(demuxer->v_streams[id]){
         mp_msg(MSGT_DEMUXER,MSGL_WARN,MSGTR_VideoStreamRedefined,id);
     } else {
diff --git a/libmpdemux/demuxer.h b/libmpdemux/demuxer.h
index 89d08af141..b9389f7704 100644
--- a/libmpdemux/demuxer.h
+++ b/libmpdemux/demuxer.h
@@ -71,6 +71,9 @@ typedef struct demuxer_info_st {
   char *copyright;
 } demuxer_info_t;
 
+#define MAX_A_STREAMS 256
+#define MAX_V_STREAMS 256
+
 typedef struct demuxer_st {
   stream_t *stream;
   int synced;  // stream synced (used by mpeg)
@@ -86,8 +89,8 @@ typedef struct demuxer_st {
   demux_stream_t *sub;   // dvd subtitle buffer/demuxer
 
   // stream headers:
-  void* a_streams[256]; // audio streams (sh_audio_t)
-  void* v_streams[256]; // video sterams (sh_video_t)
+  void* a_streams[MAX_A_STREAMS]; // audio streams (sh_audio_t)
+  void* v_streams[MAX_V_STREAMS]; // video sterams (sh_video_t)
   char s_streams[32];   // dvd subtitles (flag)
   
   void* priv;  // fileformat-dependent data