diff --git a/libavformat/tcp.c b/libavformat/tcp.c
index 0aabc9db07..4016c0e1ac 100644
--- a/libavformat/tcp.c
+++ b/libavformat/tcp.c
@@ -46,7 +46,7 @@ typedef struct TCPContext {
 static const AVOption options[] = {
     { "listen",          "Listen for incoming connections",  OFFSET(listen),         AV_OPT_TYPE_INT, { .i64 = 0 },     0,       1,       .flags = D|E },
     { "timeout",     "set timeout (in microseconds) of socket I/O operations", OFFSET(rw_timeout),     AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
-    { "listen_timeout",  "Connection awaiting timeout",      OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
+    { "listen_timeout",  "Connection awaiting timeout (in milliseconds)",      OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
     { NULL }
 };