Almost perfect. Only two features lack:
1) Prolong subtitles. It would be great to be able to prolong subtitles for, say, 2-3 seconds when there is no next line, or just until the next line begins otherwise.
2) Always use subtitles stored with the video if available. Currently, if the timestamps in two languages differ, you show one stored and one translated subtitle, even if the video has stored subtitles in the second language (but the timestamps do not match the first subtitle).