diff --git a/src/videostream.c b/src/videostream.c
index 5ab9af3..d2ee0a5 100644
--- a/src/videostream.c
+++ b/src/videostream.c
@@ -142,7 +142,7 @@ void video_stream_iterate(VideoStream *stream){
 		ms_filter_call_method_noarg(stream->output,
 			MS_VIDEO_OUT_HANDLE_RESIZING);
 	*/
-	if (stream->evq){
+	if ((stream!= NULL) && (stream->evq!=NULL)){
 		OrtpEvent *ev=ortp_ev_queue_get(stream->evq);
 		if (ev!=NULL){
 			if (ortp_event_get_type(ev)==ORTP_EVENT_RTCP_PACKET_RECEIVED){
@@ -208,6 +208,7 @@ int video_stream_start (VideoStream *stream, RtpProfile *profile, const char *re
 	pt=rtp_profile_get_payload(profile,payload);
 	if (pt==NULL){
 		ms_error("videostream.c: undefined payload type.");
+		video_stream_free(stream);
 		return -1;
 	}
 	stream->encoder=ms_filter_create_encoder(pt->mime_type);
@@ -215,6 +216,7 @@ int video_stream_start (VideoStream *stream, RtpProfile *profile, const char *re
 	if ((stream->encoder==NULL) || (stream->decoder==NULL)){
 		/* big problem: we have not a registered codec for this payload...*/
 		ms_error("videostream.c: No codecs available for payload %i:%s.",payload,pt->mime_type);
+		video_stream_free(stream);
 		return -1;
 	}
 	
@@ -513,7 +515,7 @@ int video_stream_send_only_start(VideoStream* stream, RtpProfile *profile, const
 }
 
 void video_stream_send_only_stop(VideoStream *stream){
-	if (stream->ticker){
+	if ((stream != NULL) && (stream->ticker != NULL)){
 		ms_ticker_detach (stream->ticker, stream->source);
 		ms_filter_unlink(stream->source,0,stream->pixconv,0);
 		ms_filter_unlink (stream->pixconv, 0, stream->sizeconv, 0);
@@ -546,12 +548,14 @@ int video_stream_recv_only_start (VideoStream *stream, RtpProfile *profile, cons
 	pt=rtp_profile_get_payload(profile,payload);
 	if (pt==NULL){
 		ms_error("videostream.c: undefined payload type.");
+		video_stream_free(stream);
 		return -1;
 	}
 	stream->decoder=ms_filter_create_decoder(pt->mime_type);
 	if (stream->decoder==NULL){
 		/* big problem: we have not a registered codec for this payload...*/
 		ms_error("videostream.c: No codecs available for payload %i:%s.",payload,pt->mime_type);
+		video_stream_free(stream);
 		return -1;
 	}
 #ifndef WIN32