You can hint the video player with metadata. To make the first subtitle track default: -disposition:s:0 default Or you can make it forced: -disposition:

You can hint the video player with metadata. To make the first subtitle track default: -disposition:s:0 default Or you can make it forced: -disposition:s:0 forced And to clear the disposition of the second subtitle track (if it was default in the source stream) -disposition:s:1 The problem is that video players are inconsistent in term of how they honour these parameters.