Ytdyklly

In bash I don't know how to do that. I need to do a bash-script. At stdin I have .srt file of subtitles in this format:

num

HH:MM:SS,SSS --> HH:MM:SS,SSS

text line 1

text line 2

...

HH:MM:SS,SSS start and finish of title for text.

Script must shift seconds. (it can be + or -)

Example:

$cat bmt.srt

5

00:01:02,323 --> 00:01:05,572

Hello, my frieds!

6

....



$./shifter.sh +3<mbt.srt

5

00:01:05,323 --> 00:01:08,572

Hello, my frieds!

6

I need to grab all HH:MM:SS and convert them to seconds firstly. Is somebody able do this without sed?

Unless the subtitle file spans more than 24 hours, you can use date for this:

#!/usr/bin/env bash



set -o errexit -o noclobber -o nounset -o pipefail



date_offset="$1"



shift_date() {

    date --date="$1 $date_offset" +%T,%N | cut -c 1-12

}



while read -r line

do

    if [[ $line =~ ^[0-9][0-9]:[0-9][0-9]:[0-9][0-9],[0-9][0-9][0-9] --> [0-9][0-9]:[0-9][0-9]:[0-9][0-9],[0-9][0-9][0-9]$ ]]

    then

        read -r start_date separator end_date <<<"$line"

        new_start_date="$(shift_date "$start_date")"

        new_end_date="$(shift_date "$end_date")"

        printf "%s %s %sn" "$new_start_date" "$separator" "$new_end_date"

        echo "New date"

    else

        printf "%sn" "$line"

    fi

done

For some reason you need to use decimal numbers with this, but it works:

$ ./shifter.sh "+3.0 seconds" < bmt.srt

5

00:01:05,323 --> 00:01:08,572

New date

Hello, my frieds!

6

Perl solution. I did not use any classical time handling module, as miliseconds handling is generally poorly supported.

#!/usr/bin/perl

use warnings;

use strict;



use constant FACTORS => (60 * 60 * 1000,

                              60 * 1000,

                                   1000,

                                      1);



sub time2ms {

    my $time = shift;

    my ($ms, $i) = (0, 0);

    $ms += (FACTORS)[$i++] * $_ for split /[^0-9]/, $time;

    return $ms;

}





sub ms2time {

    my $ms = shift;

    my $str = q();

    for my $i (0 .. 3) {

                $str .= sprintf +($i == 3 ? '%03d' : '%02d')

                                    . (':', ':', ',', q())[$i],

                                $ms / (FACTORS)[$i];

        $ms = $ms % (FACTORS)[$i];

    }

    return $str;

}





my $diff   = 1000 * shift;

my $TIME_R = qr/[0-9]{2}:[0-9]{2}:[0-9]{2},[0-9]{3}/;

while (<>) {

    if (my ($from, $to) = /($TIME_R) --> ($TIME_R)/) {

        my $i = 0;

        for my $time ($from, $to) {

            $time = time2ms($time) + $diff;

            print ms2time($time), (' --> ', "n")[$i++];

        }

    } else {

        print;

    }

}