fix help page

main.cpp

@@ -41,8 +41,9 @@ static void print_help()
 	printf("                                          mode 1 usually introduces less latency, but you have to care about mtu.\n");
 	printf("    --mtu                 <number>        mtu. for mode 0, the program will split packet to segment smaller than mtu value.\n");
 	printf("                                          for mode 1, no packet will be split, the program just check if the mtu is exceed.\n");
+	printf("                                          default value: 1250. you typically shouldnt change this value.\n");
     printf("    -q,--queue-len        <number>        fec queue len, only for mode 0, fec will be performed immediately after queue is full.\n");
-	printf("                                          default value: 1250\n");
+	printf("                                          default value: 200. \n");
 	printf("    -j,--jitter           <number>        simulated jitter. randomly delay first packet for 0~<number> ms, default value: 0.\n");
 	printf("                                          do not use if you dont know what it means.\n");
 	printf("    -i,--interval         <number>        scatter each fec group to a interval of <number> ms, to protect burst packet loss.\n");