efficient coding of digital signals

 by C. Helmrich

Welcome to the web site of ecodis, a project initiated by Christian Helmrich in 2005 to support and promote the development and use of efficient codecs (coders/decoders) for digital signals. Project ecodis currently focuses on digital audio and video signals such as music, speech, movies, and TV broadcasts (including still pictures) but may also address virtual reality related signals like haptic or object motion/acceleration data in the future.

   The ecodis project logo illustrates the two basic aspects of an efficient codec. First, most signals contain both redundant and irrelevant components, which are unnecessary for a perceptually accurate signal reconstruction by the decoder and can, therefore, be removed by the coder. Notice how the i-dot and the lower third of all letters in the logo can be deleted, but the text remains legible:

Second, an efficient codec divides a signal into several local segments (blocks) and each of these segments into the underlying components it consists of (using transformation). The resulting data are then processed separately. This «divide and conquer» approach is visualized by the pink i-dot in the logo, which has been segmented into four blocks:

The sub-pages of this web site contain further information on efficiency and coding.

Update Nov. 2018 Project ecodis was established for fully non-commercial, non-profit, educational purposes, and its goal is to remain independent. The sub-pages and con­tent provided thereon are, thus, not affiliated with any corporation or organization and, unless noted otherwise, solely represent the opinions and conclusions of the author.