GAIA Image Transcoder


Requirements
Licensing
Download
Installation
Usage

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GAIA Image Transcoder
The image transcoder for mobile applications

Transcoding is the process by which a data object in one representation is converted into another representation. Typical examples include conversion between different formats of the same media type (e.g., an image encoded in a certain format is transcoded into an image encoded in a second format), as well as conversion between media types (e.g., speech to text). In addition to format conversion, transcoding also allows a data object to be compressed or transformed.

GAIA Image Transcoder (GIT) is an open source library that operates image transcoding, with a special focus on mobile applications. GIT was originally developed by Open Reply team as a part of a content adaptation and delivery framework and its publication under LGPL license is the first step of the entire framework release process.

GIT comes in two parts:

  • a transformation and transcoding library that performs image adaptation to mobile device using information retrieved from WURFL file
  • a very simple JSP tag library that enables library utilization into a J2EE environment

The transcoding library works as a transformation pipeline. The pipeline is composed by a set of filters. A filter could operate directly on the image body or indirectly on the associated meta-information. GIT architecture supports the management cycle of such pipes while GIT tag libraries simplifies their definition.

At present GIT supports the following set of filters:

Device adapter receives in input the device capabilities and resizes the image to conform it to width and height of the screen
Color quantizer optimizes the colour depth of the supplied image on the bases of the device capabilities
Transcoder
receives in input the device capabilities and encodes the image to conform it to supported formats
Textoverlay overlays some texts to the image (e.g. copyright messages)
MediaRetriver
given an URI (Universal Resource Identifier) returns the associated image

The set of filters can be extended in the future, adding for example:

ROI (Region of Interest) allows the definition of regions of interest (useful for previewing)
DRM (Digital Rights Management) helps to preserve intellectual properties associated to an image (forwardlock)


Requirements
GIT can work both as a transcoding library to be used in any kind of applications (not only mobile) and as JSP tag library.
GIT has the following dependencies, which are bundled with the current distribution:

Licensing
The Gaia Image Transcoder is distributed under the LGPL license.

Download
Gaia Image Transcoder can be downloaded here.

Installation
Copy the content of the directory "webdeploy" under your application server. If you need to modify, recompile and repackage we suggest you to use the provided build.xml file. In this case make sure that you had defined the CATALINA_HOME enviroment variable or update the script with the location of your server libraries.

Usage
You can find a detailed user guide reference inside the package you download. You can also refer to the transcoding library API reference inside doc directory.


For more information about GAIA Reply please visit www.gaiareply.eu.