The WebVTT format is a standard captionning format used for HTML5 videos and HTTP Live Streaming (HLS).
Add this line to your application's Gemfile:
gem 'webvtt-ruby'
And then execute:
$ bundle
Or install it yourself as:
$ gem install webvtt-ruby
To parse a webvtt file:
require "webvtt"
webvtt = WebVTT.read("path/sub.vtt")
webvtt.cues.each do |cue|
puts "identifier: #{cue.identifier}"
puts "Start: #{cue.start}"
puts "End: #{cue.end}"
puts "Style: #{cue.style.inspect}"
puts "Text: #{cue.text}"
puts "--"
endYou can also convert an SRT file to a standard WebVTT file:
webvtt = WebVTT.convert_from_srt("path/sub.srt", "path/sub.vtt")
puts webvtt.to_webvttSegmenting is required to work with HLS videos.
WebVTT.segment("subtitles/en.vtt", :length => 10, :output => "subtitles/en-%05d.vtt", :playlist => "subtitles/en.m3u8")It will also generate the playlist in m3u8:
#EXTM3U
#EXT-X-TARGETDURATION:17
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXTINF:13,
en-00000.vtt
#EXTINF:17,
en-00001.vtt
#EXTINF:12,
en-00002.vtt
#EXT-X-ENDLIST
To use the segmented webvtt files with your HLS playlist:
#EXTM3U
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="English",DEFAULT=NO,AUTOSELECT=YES,FORCED=NO,LANGUAGE="en",URI="subtitles/en.m3u8"
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=300000,SUBTITLES="subs"
demo-300000.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=600000,SUBTITLES="subs"
demo-600000.m3u8
You can also segment webvtt files using the command line webvtt-segmenter:
$ webvtt-segmenter -i subtitles/en.vtt -t 10 -m subtitles/en.m3u8 -o "subtitles/en-%05d.vtt"
$ webvtt-segmenter -h
Usage: bin/webvtt-segmenter [--arg]
-i, --input [PATH] WebVTT or SRT file
-b, --base-url [URL] Base URL
-t, --target-duration [DUR] Duration of each segments. Default: 10
-o, --output [PATH] Path where WebVTT segments will be saved. Default: fileSequence-%05d.vtt
-m, --playlist [PATH] Path where the playlist in m3u8 will be saved. Default: prog_index.m3u8
webvtt-ruby was written in a few hours because there was no open source tool to segment webvtt files. It's not perfect at all but it does the job.
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Added some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request
Bruno Celeste