srt_tools contains utilities written to process SRT files. All utilities use the Python srt library internally.

You can call srt directly to see a list of all available utilities.

srt [utility-name] [args ...]

Arbitrary things can be done with srt process and srt lines-matching, for example:

# Strip HTML
srt process -m re -f 'lambda sub: re.sub("<[^<]+?>", "", sub)'

# Only keep Chinese subtitles
srt lines-matching -m hanzidentifier -f hanzidentifier.has_chinese

• deduplicate removes subtitles with duplicate content. If you have subtitles which mistakenly repeat the same content in different subs at roughly the same time, you can run this tool to remove them.
• fixed-timeshift does fixed time correction. For example, if you have a movie that is consistently out of sync by two seconds, you can run this tool to shift the entire subtitle two seconds ahead or behind.
• linear-timeshift does linear time correction. If you have a movie that runs slower or faster than the subtitle that you have, it will repeatedly lose sync. This tool can apply linear time corrections to all subtitles in the SRT, resyncing it with the video.
• lines-matching takes a function and removes lines that don't return true when passed to it. For example, you can keep only lines that contain Chinese by installing the hanzidentifier package, and running srt lines-matching -m hanzidentifier -f hanzidentifier.has_chinese < input.
• mux can mux multiple subtitles together into one. For example, if you have a Chinese subtitle and an English subtitle, and you want to have one subtitle file that contains both, this tool can do that for you. It also supports clamping subtitles starting or ending at similar times to the same time to avoid subtitles jumping around the screen.
• normalise standardises and cleans up SRT files. For example, it removes spurious newlines, normalises timestamps, and fixes subtitle indexing to a format that all media players should accept, with no noncompliant data.
• play plays subtitles in the terminal at the time they are scheduled to display (note: it does not clear them from the screen afterwards). If you need to fast-forward to some point, you can combine it with fixed-timeshift.
• process allows processing text freely. It takes a function, similarly to lines-matching, and changes SRT content into the return value. For example, you can naively strip some basic HTML-like markup with srt process -m re -f 'lambda sub: re.sub("<[^<]+?>", "", sub)'. HTML-like syntax is especially prevalant in SSA/ASS subtitles that have been directly converted to SRT.