diff --git a/fec_manager.cpp b/fec_manager.cpp
index d571688..729a54a 100644
--- a/fec_manager.cpp
+++ b/fec_manager.cpp
@@ -172,20 +172,21 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
     		buf[i][tmp_idx++]=(unsigned char)fec_data_num;
     		buf[i][tmp_idx++]=(unsigned char)fec_redundant_num;
     		buf[i][tmp_idx++]=(unsigned char)i;
-    		output_buf[i]=buf[i]+tmp_idx;
+    		output_buf[i]=buf[i]+tmp_idx; //////caution ,trick here.
+    		output_len[i]=tmp_idx+blob_len;
     		if(i<fec_data_num)
     		{
     			memcpy(buf[i]+tmp_idx,blob_output[i],blob_len);
     			tmp_idx+=blob_len;
     		}
     	}
-    	output_len=blob_len+sizeof(u32_t)+4*sizeof(char);/////remember to change this 4,if modified the protocol
+    	//output_len=blob_len+sizeof(u32_t)+4*sizeof(char);/////remember to change this 4,if modified the protocol
 
 		rs_encode2(fec_data_num,fec_data_num+fec_redundant_num,output_buf,blob_len);
 
 		for(int i=0;i<fec_data_num+fec_redundant_num;i++)
 		{
-			output_buf[i]=buf[i];
+			output_buf[i]=buf[i];//////caution ,trick here.
 		}
 
     	ready_for_output=1;
@@ -211,12 +212,12 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
 	return 0;
 }
 
-int fec_encode_manager_t::output(int &n,char ** &s_arr,int &len)
+int fec_encode_manager_t::output(int &n,char ** &s_arr,int *&len)
 {
 	if(!ready_for_output)
 	{
 		n=-1;
-		len=-1;
+		len=0;
 		s_arr=0;
 	}
 	else
diff --git a/fec_manager.h b/fec_manager.h
index 656d358..d6a3f15 100644
--- a/fec_manager.h
+++ b/fec_manager.h
@@ -35,7 +35,7 @@ struct anti_replay_t
 
 		if(st.find(seq)!=st.end() )
 		{
-			mylog(log_trace,"seq %llx exist\n",seq);
+			mylog(log_trace,"seq %u exist\n",seq);
 			return;
 			//return 0;
 		}
@@ -101,7 +101,7 @@ class fec_encode_manager_t
 	int fec_pending_time;
 	char buf[max_fec_packet_num+5][buf_len+100];
 	char *output_buf[max_fec_packet_num+5];
-	int output_len;
+	int output_len[max_fec_packet_num+5];
 	int ready_for_output;
 	u32_t seq;
 	int counter;
@@ -116,7 +116,7 @@ public:
 	u64_t get_timer_fd64();
 	int re_init(int data_num,int redundant_num,int mtu,int pending_num,int pending_time);
 	int input(char *s,int len/*,int &is_first_packet*/);
-	int output(int &n,char ** &s_arr,int &len);
+	int output(int &n,char ** &s_arr,int *&len);
 };
 struct fec_data_t
 {
diff --git a/main.cpp b/main.cpp
index 83f4a3f..6dd2af2 100644
--- a/main.cpp
+++ b/main.cpp
@@ -121,10 +121,10 @@ int delay_send(my_time_t delay,const dest_t &dest,char *data,int len)
 int from_normal_to_fec(conn_info_t & conn_info,char *data,int len,int & out_n,char **&out_arr,int *&out_len,int *&out_delay)
 {
 	static int out_delay_buf[max_fec_packet_num+100]={0};
-	static int out_len_buf[max_fec_packet_num+100]={0};
+	//static int out_len_buf[max_fec_packet_num+100]={0};
 	static int counter=0;
 	out_delay=out_delay_buf;
-	out_len=out_len_buf;
+	//out_len=out_len_buf;
 
 	if(0)
 	{
@@ -150,14 +150,9 @@ int from_normal_to_fec(conn_info_t & conn_info,char *data,int len,int & out_n,ch
 		//char **s_arr;
 		//int s_len;
 
-		int tmp_out_len;
-		conn_info.fec_encode_manager.output(out_n,out_arr,tmp_out_len);
 
-		for(int i=0;i<out_n;i++)
-		{
-			out_len_buf[i]=tmp_out_len;
-		//	out_delay_buf[i]=100*i;
-		}
+		conn_info.fec_encode_manager.output(out_n,out_arr,out_len);
+
 
 	}
 
@@ -900,15 +895,15 @@ int unit_test()
 
 		int n;
 		char **s_arr;
-		int len;
+		int *len;
 
 
 		fec_encode_manager.output(n,s_arr,len);
-		printf("<n:%d,len:%d>",n,len);
+		printf("<n:%d,len:%d>",n,len[0]);
 
 		for(int i=0;i<n;i++)
 		{
-			fec_decode_manager.input(s_arr[i],len);
+			fec_decode_manager.input(s_arr[i],len[i]);
 		}
 
 		{
@@ -937,16 +932,16 @@ int unit_test()
 
 		int n;
 		char **s_arr;
-		int len;
+		int * len;
 
 
 		fec_encode_manager.output(n,s_arr,len);
-		printf("<n:%d,len:%d>",n,len);
+		printf("<n:%d,len:%d>",n,len[0]);
 
 		for(int i=0;i<n;i++)
 		{
 			if(i==1||i==3||i==5||i==0)
-			fec_decode_manager.input(s_arr[i],len);
+			fec_decode_manager.input(s_arr[i],len[i]);
 		}
 
 		{