Always keep a -c copy backup of the original untouched audio track. The 5.1 mix of Ramin Djawadi’s "The Lannister Send Their Regards" deserves lossless preservation.
ffmpeg -i original_s03e04.mkv -map 0:s:m:forced? -c copy forced_subtitles.ass game of thrones season 03 ffmpeg
By a Video Encoding Archivist