diff --git a/avconv.c b/avconv.c
index 13968da4f92263dfaea9fe7a01ff52e37254355f..0ee76285f0e9cee209ac05d3c260f4a45ba0c078 100644
--- a/avconv.c
+++ b/avconv.c
@@ -1972,6 +1972,8 @@ static int transcode_init(void)
                    "Error initializing the output stream codec context.\n");
             exit_program(1);
         }
+
+        ost->st->time_base = ost->enc_ctx->time_base;
     }
 
     /* init input streams */