jpeg-js

A pure javascript JPEG encoder and decoder for node.js

Installation

This module is installed via npm:

$ npm install jpeg-js

Example Usage

Decoding JPEGs

var jpegData = fs.readFileSync('grumpycat.jpg');
var rawImageData = jpeg.decode(jpegData);

Encoding JPEGs

var width = 320, height = 180;
var frameData = new Buffer(width * height * 4);
var i = 0;
while (i < frameData.length) {
  frameData[i++] = 0xFF; // red
  frameData[i++] = 0x00; // green
  frameData[i++] = 0x00; // blue
  frameData[i++] = 0xFF; // alpha - ignored in JPEGs
}
var rawImageData = {
  data: frameData,
  width: width,
  height: height
};
var jpegImageData = jpeg.encode(rawImageData, 50);

License

Decoding

This library builds on the work of two other JPEG javascript libraries, namely jpgjs for the decoding which is licensed under the Apache 2.0 License below:

Copyright 2011 notmasteryet

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Encoding

The encoding is based off a port of the JPEG encoder in as3corelib.

The port to Javascript was done by by Andreas Ritter, www.bytestrom.eu, 11/2009.

The Adobe License for the encoder is:

Adobe

Copyright (c) 2008, Adobe Systems Incorporated All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name of Adobe Systems Incorporated nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.