add-time-to-srt

Name

add-time-to-srt.sh - Add time stamps to a subtitle file in srt format

Purpose

When the subtitles of a subtitle file (in .srt format) are not in synch with the movie, one might want to resynchronize the subtitle file using some tool like the SubFix application.

Synopsis

    add-time-to-srt.sh [option] [file]

Description

This shell script takes as input a subtitle file (in .srt format) and writes it on the standard output with some additions.

• It inserts:

  • in each existing subtitle,
  • the precise beginning time of this subtitle,
  • at some place in the existing subtitle, either:
    • above its first line,
    • or to the left of its first line,
    • or to the right of its first line,
    • or below its last line (by default).

• It inserts:

  • a new subtitle with the current time,
  • every 1/10 s (by default),
  • between existing subtitles.

Install

Clone this repository or copy its files in some directory.

Both files "add-time-to-srt.sh" and "add-time-to-srt.awk" must be in the same directory.

If this directory is referenced in the variable "$PATH" of your shell, you can launch the command with add-time-to-srt.sh ... otherwise, you'll have to type the full path path/to/dir/add-time-to-srt.sh ....

Requirements

This script should run on any machine with bash and awk (macOS, linux, un*x, cygwin...).

It has originally been developped under OSX El Capitan 10.11.6 with GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin15) and awk version 20070501. As it does not use any known bashism, it could be run from any shell.

Global usage

• Save the original subtitle file:

    mv the-movie.srt the-movie-sav.srt

• Add timetags:

    add-time-to-srt.sh -v end_time='01:30:00,000' the-movie-sav.srt > the-movie.srt

• Open the movie file (with VLC, for example)

  • find the beginning time of the first subtitle (using the pause button)
  • find the beginning time of the last subtitle (using the pause button)

• Remove the file with superfluous subtitles:

    rm the-movie.srt

• Launch the SubFix application.
  • Open the original subtitle file the-movie-sav.srt.
  • Fix the first and last subtitle times.
  • Save the fixed subtitle file:
    menu File > Save as... the-movie.srt

Script options

• -v style=[top | left | right | bottom] (default: 'bottom')

Choose the place to insert its timetag in an existing subtitle: - top: above its first line, - left: to the left of its first line, - right: to the right of its first line, - bottom: below its last line (by default).

• -v delta='hh:mm:ss,xxx' (default: '00:00:00,100' = 1/10th sec)

Choose the delay between new pure timetag subtitles.

• -v end_time='hh:mm:ss,xxx'

When this option is present, insert new pure timetag subtitles after the last existing subtitle until the specified end_time.

• -v first_st_index=<n> (default: 1)

Start the numbering of subtitles from the specified index.

• -v start_time='hh:mm:ss,xxx' (default: '00:00:00,000')

Start the new timetags from the specified time.

Examples:

• Minimal command

add-time-to-srt.sh < file.srt > file_t.srt

• Print just five timetags with no input

add-time-to-srt.sh -v style=left -v start_time='00:00:01,000' \
  -v delta='00:00:00,200' -v end_time='00:00:02,000'  < /dev/null