#subtitle #rename #video #file #batch #operations #file-extension

app sub-batch

Match and rename subtitle files to video files and perfom other batch operations on subtitle files

13 releases (5 stable)

2.0.0 Dec 28, 2023
1.1.1 Oct 8, 2023
1.0.1 Nov 17, 2022
1.0.0 Jan 23, 2022
0.1.0 Apr 3, 2019

#327 in Command line utilities

Download history 10/week @ 2024-02-20 8/week @ 2024-02-27 1/week @ 2024-03-12 1/week @ 2024-03-19 19/week @ 2024-03-26 7/week @ 2024-04-02

80 downloads per month

MIT and LGPL-3.0

1.5K SLoC


Match and rename subtitles to videos and perform other batch operations on subtitles.


Precompiled binaries (Linux and Windows)


Nix package (credit to: https://github.com/erictapen)



cargo install sub-batch


To see all subcommands and options, run sub-batch help.

Problem: I want to rename subtitle files to match their corresponding video file

Use the sub-batch rename command to match and rename subtitles to videos. It works by scanning the subtitle and video file names for numbers, and renaming the subtitle to the video file that contains the same number. For example, if we have the following files in a directory:


run sub-batch rename:

> sub-batch rename
NameOfSeries_E01.srt -> 1_NameOfSeries.mkv
NameOfSeries_E02.srt -> 2_NameOfSeries.mkv
NameOfSeries_E03.srt -> 3_NameOfSeries.mkv

Renaming when numbers are in different positions

Running sub-batch rename on the following files will fail.


This is because the first number in each sub (1337) is not present in the video files, so no match can be made. The easiest way to solve this is to pass the --rev flag:

> sub-batch rename --rev
1337_NameOfSeries_E01.srt -> 1_NameOfSeries.mkv
1337_NameOfSeries_E02.srt -> 2_NameOfSeries.mkv
1337_NameOfSeries_E03.srt -> 3_NameOfSeries.mkv

by default, sub-batch looks for the first number form left-to-right in the file name, but --rev changes the scan direction to right-to-left. You can also use the --rs (reverse sub) and --rv (reverse video) flags to only change the direction of sub or video files.

When the episode number isn't the first or last number in the file name, you can define a subsection of the file name and sub-batch will only look for numbers in this area.

This is done with the --subarea and --videoarea options, which take a regular expression that defines the area to scan for numbers in. For example, if you have the following files:



> sub-batch rename --subarea "file.*"
1sub_file_08_xx2.srt -> video8.mp4

Note that the regex does not have to match a number, it just defines the sub area in the file name where the number scan starts at.

Problem: I want to change subtitle timings

To change the subtitle timings for all subtitles in the directory use the time subcommand, for example:

sub-batch time 100

which moves all timings forward by 100 ms, or:

sub-batch time -50

which moves all timings back by 50 ms.

Adjusting subtitle timings with alass

alass (https://github.com/kaegi/alass) can automatically adjust timings of a subtitle file and fix things such as gaps for commercial breaks given the video file of the subtitle. To run alass-cli on all subtitle/video matches in parallel, run:

sub-batch alass

Arguments to alass-cli can be given by putting them after the alass subcommand in quotes:

sub-batch alass "--split-penalty 10"

Adjusting subtitle timings interactively with mpv

If mpv (https://mpv.io) is installed sub-batch can use mpv to adjust timings interactively and have the updated subtitles auto-refresh in mpv. To enter this mode run:

sub-batch time-mpv

and follow the on-screen instructions to adjust the timings.

Note that at least one matched (same name except for extension) video file/subtilte file pair must exist in the target directory. sub-batch will only use the first matched pair it finds when adjusting, but the timing adjustment is applied to all subtitle files in the directory, same as sub-batch time command.

Problem: I want to target only certain subtitle/video files

You can give a regular expression to filter the subs/videos that should be included when running any of the subcommands. For example, to only change timings of subtitles with the .srt extension in the target directory, run:

sub-batch --filter-sub "\.srt" time -50

Any other subtile files in the target directory are ignored. Video files can be filtered the same way with the --filter-video option.

Problem: I want to match more than one subtitle to a single video file using secondary extensions

Let's say we have the following files:


Running sub-batch rename will match all three subtitle files:

> sub-batch rename
NameOfSeries_E01.en.srt -> 1_NameOfSeries.mkv
NameOfSeries_E01.jp.srt -> 1_NameOfSeries.mkv
NameOfSeries_E01.srt    -> 1_NameOfSeries.mkv

and after renaming the secondary extensions are not deleted:


Secondary extensions are treated as part of the file extension only if the following two conditions are true:

  1. The secondary extension is no longer than 3 characters long.
  2. The secondary extension doesn't contain a number.

The length check exists because mpv (by default) doesn't recognize secondary extensions longer than 3 characters, and the number check exists because a number in the secondary extension could be used as the match number.

If any of the above conditions are false, the secondary extension is treated as part of the file stem which means that the subtitle can only be uniquely matched to a single video.

You can change this default behavior with the --sec-always and --sec-never flags which can be given to the rename and alass subcommands. --sec-always unconditionally enables secondary extensions no matter how long or what characters they contain, while --sec-never disables handling of secondary extensions completely.


~560K SLoC