Captions - Subtitle Editor and Converter

Captions can read subtitles of various formats, modify them and convert the subtitle to other formats. Currently captions supports SRT, WebVTT files.

Supported Features

• Read subtitles
• Move subtitles
• Increase duration
• Filter subtitles
• Change frame rate
• Convert to other format (SRT, WebVTT)

Features Planned

• Read subtitle properties (Font Style, Aligment, Position etc.)
• Delete subtitles
• Change subtitle fonts
• Command Line Interface
• Spell Check
• And More...

Usage

Read subtitle file:

s = Captions::SRT.new('test.srt')
s.parse

s = Captions::VTT.new('test.vtt')
s.parse

Filter subtitles:

Once the subtitle file has been parsed. Every subtitle will get start_time, end_time, duration and text. All the values are stored in milliseconds. Captions::InvalidSubtitle error will be thown if start-time or end-time cannot be found for a subtitle.

View all subtitle text:

s.cues.map { |c| c.text }

Filter subtitles based on condition:

s.cues { |c| c.start_time > 1000 }
s.cues { |c| c.end_time > 1000 }
s.cues { |c| c.duration > 1000 }

To get all subtitles:

s.cues.each { |c| puts c }

Move Subtitle:

s.move_by(1000)
s.move_by(1000) { |c| c.start_time > 3000 }

Former command moves all subtitles by 1 second. Later moves the subtitles which are starting after 3 seconds by 1 second.

Increase Duration:

s.increase_duration_by(1000)
s.increase_duration_by(1000) { |c| c.start_time > 3000 }

Former command increases duration of all subtitles by 1 second. Later increases the duration of subtitles which are starting after 3 seconds by 1 second.

Change Frame Rate:

All subtitles are parsed based on 25 frames/second by default. This can be changed by passing frame rate at the time of reading the subtitle file.

s = Captions::SRT.new('test.srt', 29.97)
s.parse

Frame rate can also be changed after parsing. This command changes all the subtitles which are parsed in different frame-rate to new frame-rate.

s.set_frame_rate(29.97)

Convert to Other Format:

Subtitles parsed in one format can be converted to other format. Currently export is supported for SRT and WebVTT. Other formats will be added soon.

s = Captions::SRT.new('test.srt')
s.parse
s.export_to_vtt('test.vtt')

Subtitles can also be filtered and those filtered subtitles can be written to a file.

s = Captions::SRT.new('test.srt')
s.parse
new_cues = s.cues { |c| c.start_time > 2000 }
s.export_to_vtt('test.vtt', new_cues)

Filter subtiltes and Export:

Subtitles can be filtered with filter option. This returns a new Captions object. Once filters new object is created and cues for that becomes the result of the filter. This can be exported to other formats easily.

new_obj = s.filter { |c| c.start_time > 2000 }
new_obj.export_to_vtt('test.vtt')

Installation

Add this line to your application's Gemfile:

gem 'captions'

Or install it yourself as:

$ gem install captions

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/navinre/captions.

License

The gem is available as open source under the terms of the MIT License.