video-thumb-grid

Generates a sprite grid of video thumbnails using ffmpeg.

How to use

var fs = require('fs');
var thumbs = require('video-thumb-grid');
var grid = thumbs(fs.createReadStream('video.mov'));
grid.count(100);
grid.interval(4);
grid.start(0);
grid.render(function(err, buf){
  if (err) throw err;
  fs.writeFileSync('grid.jpg', buf);
});

API

Grid(Stream input)

Constructs a new Grid with the given input Readable stream.

Grid(String input)

Constructs a new Grid with the given input fs path.

Grid#count()

Returns the number of thumbnails to generate. Defaults to 100.

Grid#count(Number count)

• Sets the number of thumbnails to generate to count.
• Returns the Grid instance object.

Grid#rows()

Returns the number of rows in the grid. Defaults to the creating a "square" by calculating the square root of count.

Grid#rows(Number count)

• Sets the number of thumbnails to generate to count.
• Returns the Grid instance object.

Grid#interval()

Returns how many seconds to wait between thumbs. Defaults to 1.

Grid#interval(Number int)

• Sets how many seconds to wait between thumbs to int.
• Returns the Grid instance object.

Grid#start()

Returns the number of seconds at which we start capturing thumbs. Defaults to 0.

Grid#start(Number secs)

• Sets how many seconds to seek to.
• Returns the grid instance object.

Grid#width()

Returns the width of each individual thumb in the grid. Defaults to 192.

Grid#width(Number w)

• Sets width of each individual thumb to w.
• Returns the Grid instance object.

Grid#height()

Returns the height of each individual thumb in the grid. Defaults to 144.

Grid#height(Number h)

• Sets height of each individual thumb to h.
• Returns the Grid instance object.

Grid#quality()

Returns the quality of the resulting JPEG. Defaults to 50.

Grid#quality(Number q)

• Sets the quality of the resulting JPEG to q.
• Returns the Grid instance object.

Grid#vquality()

Returns the quality of frames returned by ffmpeg. This corresponds to the q option, which takes a value from 1 (highest) to 31 (lowest). Defaults to 1.

Grid#vquality(Number q)

• Sets the ffmpeg video quality.
• Returns the Grid instance object.

Grid#debugprefix()

Returns the prefix used for debug messages. Defaults to an empty string.

Grid#debugprefix(String prefix)

• Sets the prefix for dedugging to prefix.
• Returns the Grid instance object.

Grid#render(Function fn)

• Triggers the thumbnailing process
• Calls fn with err, buf, buf being the resulting JPEG grid.
• Can be aborted by calling Grid#abort.
• Returns the Grid instance object.

Grid#abort

• Aborts the ffmpeg process, if ongoing, or the grid composition.
• Returns the Grid instance object.

Grid#cmd()

Returns the program that will be called. Defaults to ffmpeg.

Grid#cmd(String cmd)

• Sets the program that will be run to cmd.
• Returns the Grid instance object.

Grid#proc

• Property that holds the ffmpeg ChildProcess.

Grid#debug(String msg, String type)

• Outputs the debugging msg to stdout when DEBUG is enabled. The type can be info or ffmpeg which helps separate the noise.

Notes:

• If the interval and start combination can't possibly meet count due to the length of the video, the grid will be populated with empty spaces.

Requirements

• ffmpeg must be installed an available in $PATH
• libjpeg needs to be installed for the picha dependency to build

Authors

• Nick Momrik (@nickmomrik)
• Guillermo Rauch (@guille)

License

MIT – Copyright (c) 2014 Automattic, Inc.