Caption And Subtitle Converter for PHP

Convert and edit subtitles and captions.

Supported formats

Format	Extension
SubRip	.srt
WebVTT	.vtt
Spruce Technologies SubTitles	.stl
Youtube Subtitles	.sbv
SubViewer	.sub
Advanced Sub Station	.ass
DFXP	.dfxp
TTML	.ttml
QuickTime	.qt.txt

Installation

composer require mantas-done/subtitles

Usage

Convert .srt file to .vtt:

// add namespace
use \Done\Subtitles\Subtitles;

Subtitles::convert('subtitles.srt', 'subtitles.vtt');

Manually create file

$subtitles = new Subtitles();
$subtitles->add(0, 5, 'This text is shown in the beggining of video for 5 seconds');
$subtitles->save('subtitles.vtt');

Load subtitles from existing file

$subtitles = Subtitles::load('subtitles.srt');

Load subtitles from string

$string = "
1
00:02:17,440 --> 00:02:20,375
Senator, we're making our final approach
";  

$subtitles = Subtitles::load($string, 'srt');

Save subtitles to file

$subtitles->save('subtitler.vtt');

Get file content without saving to file

echo $subtitles->content('vtt');

Add subtitles

$subtitles->add(0, 5, 'some text'); // from 0, till 5 seconds  

// Add multiline text
$subtitles->add(0, 5, [
    'first line',
    'second line',
]);

Remove subtitles

$subtitles->remove(0, 5); // from 0, till 5 seconds

Add 1 second to all subtitles

$subtitles->shiftTime(1);

Subtract 0.5 second

$subtitles->shiftTime(-0.5);

Add 5 second to subtitles starting from 1 minute till 2 mintes

$subtitles->shiftTime(5, 60, 120);

Example: shift time gradually by 2 seconds over 1 hour video. At the beginning of the video don't change time, in the middle shift time by 1 second. By the end of video, shift time by 2 seconds.

$subtitles->shiftTimeGradually(2, 0, 3600);

How to add new subtitle format?

You need to implement ConverterContract.php interface. It has two methods.

fileContentToInternalFormat($file_content)  
  
internalFormatToFileContent($internal_format)

Basically what your implementation should be able to do, is convert subtitle file to "internal library's format", and from internal library's format back to subtitle file.

"Internal library's" format is used like middle ground, to be able to convert between different formats.

Best example is to look how SrtConverter.php is implemented.
And this is example of .srt file.

"Internal Format"

"Internal Format" is just a PHP array. It is used internally in library to be able to convert between different formats.

Array
(
    [0] => Array
        (
            [start] => 137.44
            [end] => 140.375
            [lines] => Array
                (
                    [0] => Senator, we're making
                    [1] => our final approach into Coruscant.
                )
        )
    [1] => Array
        (
            [start] => 140.476
            [end] => 142.501
            [lines] => Array
                (
                    [0] => Very good, Lieutenant.
                )
        )
)

[start] - when to start showing text (float - seconds)
[end] - when to stop showing text (float -seconds)
[lines] - one or more text lines (array)

Running Tests

Simplest way is to download and put phpunit.phar file into the main directory of the project. Then run the command:

php phpunit.phar

Contribution

You can contribute in any way you want. If you need some guidance, choose something from this table:

Task	Difficulty	Description
Add new formats	Medium	Supporting more formats is nice. Some popular formats: .mcc, .cap
Refactor StlConverter.php file	Easy	.stl format is very similar to .srt. The only problem is that StlConverter.php code can be simplified a lot (check SrtConverter.php as example)
Add .scc format	Hard	Format description

For now library should support only basic features (several lines of text). No need to support different text styles or positioning of text.

Report Bugs

If some file is not working with the library, please create and issue and attach the file.

hopeseekr-contribs/subtitles