You add the .idx file as the subtitle file. The .idx file itself points to the associated .sub file, so you don't have to tell ffmpegX about the .sub file. Note: this only works for encodings with the 'DVD mpeg2enc' preset and 'Decode with mplayer' activated.
Tonight is the night- Game of Thrones, season 6, premieres on HBO. The show begins at 8 p.m. CST, and will last for one hour.
Often heralded as not only one of the best shows on HBO, but also one of the best series of all time, Game of Thrones is an epic tale of royal feuds, dynastic conflict, and the struggle for ultimate control in the Seven Kingdoms of Westeros.