diff --git a/syncplay/constants.py b/syncplay/constants.py
index 980bfb5..f20d44e 100644
--- a/syncplay/constants.py
+++ b/syncplay/constants.py
@@ -138,7 +138,7 @@ USERLIST_GUI_USERNAME_COLUMN = 0
 USERLIST_GUI_FILENAME_COLUMN = 3
 
 MPLAYER_SLAVE_ARGS = ['-slave', '--hr-seek=always', '-nomsgcolor', '-msglevel', 'all=1:global=4:cplayer=4', '-af-add', 'scaletempo']
-MPV_ARGS = ['--force-window', '--idle', '--hr-seek=always', '--keep-open', '--af-add=scaletempo']
+MPV_ARGS = ['--force-window', '--idle', '--hr-seek=always', '--keep-open', '--af-add=scaletempo', '--demuxer-mkv-probe-video-duration=yes']
 MPV_SLAVE_ARGS = ['--quiet', '--input-terminal=no', '--input-file=/dev/stdin']
 MPV_SLAVE_ARGS_NEW = ['--term-playing-msg=<SyncplayUpdateFile>\nANS_filename=${filename}\nANS_length=${=length}\nANS_path=${path}\n</SyncplayUpdateFile>', '--terminal=yes']
 MPV_NEW_VERSION = False
@@ -175,4 +175,4 @@ FILEITEM_SWITCH_STREAM_SWITCH = 2
 
 SYNCPLAY_UPDATE_URL = u"http://syncplay.pl/checkforupdate?{}" # Params
 SYNCPLAY_DOWNLOAD_URL = "http://syncplay.pl/download/"
-SYNCPLAY_PUBLIC_SERVER_LIST_URL = u"http://syncplay.pl/listpublicservers?{}" # Params
\ No newline at end of file
+SYNCPLAY_PUBLIC_SERVER_LIST_URL = u"http://syncplay.pl/listpublicservers?{}" # Params