ffmpeg
Useful Commands
Embed the subtitles and compress a movie produced by final cut pro to a mp4.
ffmpeg -i movie.m4v subtitles.srt -c:s mov_text output.mp4
Compression
ffmpeg -i input.mp4 -vcodec libx264 -crf 23 -preset slow -c:a aac -b:a 128k output.mp4