diff --git a/libavformat/tcp.c b/libavformat/tcp.c
index a2426117c8..9585dc08d1 100644
--- a/libavformat/tcp.c
+++ b/libavformat/tcp.c
@@ -43,8 +43,8 @@ typedef struct TCPContext {
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "listen",          "Listen for incoming connections",  OFFSET(listen),         AV_OPT_TYPE_INT, { .i64 = 0 },     0,       1,       .flags = D|E },
-    { "timeout",         "Connection timeout",               OFFSET(timeout),        AV_OPT_TYPE_INT, { .i64 = 10000 }, INT_MIN, INT_MAX, .flags = D|E },
-    { "listen_timeout",  "Bind timeout",                     OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },    INT_MIN, INT_MAX, .flags = D|E },
+    { "timeout",         "Connection timeout (in milliseconds)", OFFSET(timeout),    AV_OPT_TYPE_INT, { .i64 = 10000 }, INT_MIN, INT_MAX, .flags = D|E },
+    { "listen_timeout",  "Bind timeout (in milliseconds)",   OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },    INT_MIN, INT_MAX, .flags = D|E },
     { NULL }
 };