SMPlayer 17.1 added support for Chromecast. Now SMPlayer 17.3 has just added the possibility to display subtitles on Chromecast (still an experimental feature).

However currently there are some limitations:

• Only external subtitles are supported.
• The subtitles must be in the same folder of the video.
• The subtitles must be in vtt format.

How to use subtitles, step by step

• First you need to convert the subtitles to vtt. You can convert subtitles in srt format to the vtt format here: http://chromecast.smplayer.info/convert-srt-to-vtt. Or just use any other tool you may find on the Internet. Store the vtt file in the same folder of the video.
• Play the video in SMPlayer and select the vtt subtitle from the menu Subtitles -> Primary track.
• Select the option Play on Chromecast from the Play menu.

Now connect to Chromecast and start playback as usual. The subtitles should be displayed on the TV screen.

Note: you can actually select a subtitle in srt or any other format in SMPlayer, but the SMPlayer Chromecast Control will try to use a subtitle file with the same name but with the vtt extension.