subsrt
Subtitle converter JavaScript library and command line tool.
Getting Started
Install the module
npm install -g subsrt
Command line
subsrt --help
subsrt convert sample.sub sample.srt
Using as Node.js library
var subsrt = require('subsrt');
var sub = "{14975}{104000}Hi, my name is...";
var srt = subsrt.convert(sub, { format: "srt", fps: 25 });
Supported subtitle formats
Command Line Arguments
Usage:
subsrt [command] [options]
Commands:
list List supported formats
parse [src] [json] Parse a subtitle file
build [json] [dst] Create a subtitle file from captions
detect [src] Detect subtitle file format, if supported
resync [src] [dst] Resync FPS or shift time (+/- offset)
convert [src] [dst] Converts a subtitle format
Options:
--help Print this message
--eol [chars] End of line chars, e.g. \r\n
--fps [fps] Frames per second for .sub format
--offset [time] Resync time shift offset in ms
--format [ext] Subtitle format to convert/build/parse
--verbose Enable detailed logging
--version Print version number
Examples:
subsrt parse sample.sbv
subsrt parse sample.srt output.json
subsrt parse sample.sub --fps 30
subsrt build input.json output.vtt
subsrt build input.json --format sbv
subsrt detect unknown.txt
subsrt convert sample.srt sample.vtt
subsrt convert --offset -250 sample.srt sample.ssa
subsrt resync --offset +3000 input.srt output.srt
subsrt resync --fps 25-30 input.sub output.sub
Using in JavaScript
The Node.js library supports converting, parsing and building subtitle file formats.
Subtitles can also be resynced by shifting time offset, extending duration or changing FPS.
List supported formats
var subsrt = require('subsrt');
var list = subsrt.list();
console.log(list.join(", "));
Format name is used in conversion options, e.g. { format: "srt" }
Use subsrt.format[name]
to access functions directly
var subsrt = require('subsrt');
var handler = subsrt.format['srt'];
To implement a new subtitle format handler do the following
var subsrt = require('subsrt');
subsrt.format['my'] = {
name: 'my',
parse: function(content, options) {
var captions = [ ];
return captions;
},
build: function(captions, options) {
var content = "";
return content;
},
detect: function(captions, options) {
if (content.indexOf("my") > 0) {
return true;
}
}
};
Detect
Recognizes format by content
var subsrt = require('subsrt');
var content = '';
content += '5' + '\r\n';
content += '00:00:16,700 --> 00:00:21,480' + '\r\n';
content += 'Okay, so we have all the ingredients laid out here' + '\r\n';
var format = subsrt.detect(content);
Parse
Parse a subtitle file
var fs = require('fs');
var subsrt = require('subsrt');
var content = fs.readFileSync('sample.srt', 'utf8');
var options = { verbose: true };
var captions = subsrt.parse(content, options);
console.log(captions);
Example of output
[
{
"type": "caption",
"index": 1,
"start": 599,
"end": 4160,
"duration": 3561,
"content": ">> ALICE: Hi, my name is Alice Miller and this is John Brown",
"text": "Hi, my name is Alice Miller and this is John Brown"
},
{
"type": "caption",
"index": 2,
"start": 4160,
"end": 6770,
"duration": 2610,
"content": ">> JOHN: and we're the owners of Miller Bakery.",
"text": "and we're the owners of Miller Bakery."
},
...
]
List of options
format
: explicitly select a parser, values: sub
, srt
, sbv
, vtt
, lrc
, smi
, ssa
, ass
, json
, default is undefined to auto detectverbose
: set to true for extra messages, console only, default: false
eol
: end of line character(s), default: \r\n
fps
: frames per seconds, sub
format onlypreserveSpaces
: keep white space lines, smi
format only
Build
Build a subtitle file
var fs = require('fs');
var subsrt = require('subsrt');
var captions = [
{
"start": 599,
"end": 4160,
"text": "Hi, my name is Alice Miller and this is John Brown"
},
{
"start": 4160,
"end": 6770,
"text": "and we're the owners of Miller Bakery."
}
];
var options = { format: 'vtt' };
var content = subsrt.build(captions, options);
fs.writeFileSync('generated.vtt', content);
List of options
format
: required, output subtitle format, values: sub
, srt
, sbv
, vtt
, lrc
, smi
, ssa
, ass
, json
, default: srt
verbose
: set to true for extra messages, console only, default: false
fps
: frames per seconds, sub
format onlycloseTags
: set to true to close tags, smi
format only
Convert
Using a single action to convert from one to another subtitle format
var fs = require('fs');
var subsrt = require('subsrt');
var srt = fs.readFileSync('sample.srt', 'utf8');
var sbv = subsrt.convert(srt, { format: 'sbv' });
fs.writeFileSync('converted.sbv', sbv);
List of options
format
: required, output subtitle format, values: sub
, srt
, sbv
, vtt
, lrc
, smi
, ssa
, ass
, json
, default: srt
verbose
: set to true for extra messages, console only, default: false
eol
: end of line character(s), default: \r\n
fps
: frames per seconds, sub
format onlyresync
: resync options, see below
Time shift (+/- offset)
Example to make an extra 3 second delay
var fs = require('fs');
var subsrt = require('subsrt');
var content = fs.readFileSync('sample.srt', 'utf8');
var captions = subsrt.parse(content);
var resynced = subsrt.resync(captions, { offset: 3000 });
Use minus sign to display captions earlier
var resynced = subsrt.resync(captions, { offset: -3000 });
Change FPS
The .sub format has captions saved in frame unit. To shift from 25 FPS to 30 FPS do the following
var fs = require('fs');
var subsrt = require('subsrt');
var content = fs.readFileSync('sample.sub', 'utf8');
var captions = subsrt.parse(content, { fps: 25 });
var resynced = subsrt.resync(content, { ratio: 30 / 25, frame: true });
Advanced resync options
Extend caption duration by 500 ms
var resynced = subsrt.resync(content, function(a) {
return [ a[0], a[1] + 500 ];
});
Source Code
Download the source code from GitHub repository.
Install required packages if any
npm install
Run the unit tests
npm test
Optionally create a folder output
in the test
folder before running the tests.
This will allow you to view the generated contents.