grunt-video-slicer

Grunt task for cutting video into sections by specified time ranges

Getting Started

This plugin requires Grunt ~0.4.1

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-video-slicer --save-dev

Additionally, this plugin requries ffmpeg with libx264 and libvpx to encode .mp4 and .webm, which are common HTML5 codecs.

brew install ffmpeg --with-libvorbis --with-nonfree --with-gpl --with-libvpx --with-pthreads --with-libx264 --with-libfaac --with-theora --with-libogg

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-video-slicer');

The "video_slicer" task

Overview

The video_slicer task will take the source video file and cut it in any number of clips you defined in the options. Clips will be encoded in *.mp4 and *.webm and optimized to be fully supported with web browser.

In your project's Gruntfile, add a section named video_slicer to the data object passed into grunt.initConfig().

grunt.initConfig({
  video_slicer: {
    options: {
      // Task-specific options go here.
    },
    my_target: {
      src: 'src/video.mp4',
      dest: 'dest_folder/'
    }
  }
})

Options

options.sections

Type: Array

Default value:

[{
  name: 'section' + i,
  time: [],
  filters: [],
  codecs: ['mp4', 'webm'],
  skip: false
}]

An array of objects containing the time range we want to cut our video into.

If a name is specified, then output video clip will be named with this name. e.g. super-movie.mp4

If a name is not specified, then output video clip will be named with default pattern section<index>. e.g. section0.mp4, section1.mp4, etc.

If a time is specified, then the video clip will be cut from time specified in the first value and will end in the time specified at second value.

If a time is not specified, then task will encode full length source file into specified codecs with specified name.

If time is specified as time: [1, 10], then the video clip will start at 1sec and will end at 10sec.

If time is specified as time: [10] or time: 10, then the video clip will start at 10sec and will end at the end of the source video file.

If codecs are specified, then the video clip will be encoded to specified formats.

If codecs are not specified, then the video clip will be encoded to default formats ['mp4', 'webm'].

If codecs is specified as codecs: 'json', then the video clip will be encoded to only json format.

If skip is specified, then the section will be excluded from the converting batch.

If filters are specified, then the video clip will be encoded with applied image filters. Available filters:

1. grayscale – will turn video black and white.

Example:

[{
  time: [0, 1.5]
}, {
  time: [1.5, 2.2],
  codecs: ['json', 'webm']
}, {
  time: [1.5, 3]
}, {
  name: 'last_part',
  time: 3,
  codecs: 'mp4'
}, {
  name: 'skipped_section',
  time: 4,
  skip: true
}]

options.emptyDestBeforeStart

Type: Boolean

Default value: false

If the value is specified, then task will empty the destination folder before starting encoding.

The value that specifies should task empty destination folder before start encoding.

Usage Examples

Default Options

The default options will generate .mp4 and .webm versions of source files. They will be named section0.mp4 and section0.webm.

grunt.initConfig({
  video_slicer: {
    options: {},
    my_target: {
      src: 'src/video.mp4',
      dest: 'dest_folder/'
    }
  }
})

Custom Options

In this example, we specify sections and a source path. We'll generate 5 video files. First, third and forth files will be encoded to mp4 and webm formats only. The second file will be encoded into json array with base64 encoded frames. The last file with full_video name will be full length source files encoded into mp4, webm and json formats.

grunt.initConfig({
  video_slicer: {
    options: {
      sections: [{
        time: [0, 1.5]
      }, {
        time: [1.5, 2.2],
        codecs: 'json'
      }, {
        time: [1.5, 3]
      }, {
        time: 3
      }, {
        name: 'full_video',
        codecs: ['mp4', 'webm', 'json'],
      }],
      emptyDestBeforeStart: true
    },
    video: {
      src: 'videos/video.mp4',
      dest: 'sections/'
  }
}
})

Release History

0.3.3

• Increased json encode default quality

0.3.2

• Added filters options

0.2.1

• Console loging improvements

0.2.0

• Section's encodeToJSON parameter changed to json codec format.
• Section's name is not required parameter anymore.
• Made refactoring to simplify code and bug fixes.

0.1.1

• Section's sequence time array changed to section's encodeToJSON parameter.

0.1.0

• Initial Release.