EVD stands for Enhanced Versatile Disc. It was developed by Beijing E-World, a consortium of companies. It was created to rival the DVD-Video format mainly in China because the licensing fees associated with DVD-Video are considered quite high, about $13–$20 per hardware video player. EVD was made to expand on the DVD-Video format, in terms of what video and audio codecs it used and of course, its ability to offer high definition video content.
The disc is the same size as CDs and DVDs and uses the same file system as DVD (UDF). On2 Technologies was to provide the video codecs for the format, VP5 and VP6, which are more efficient than the MPEG-2 video format used with DVD-Video. These codecs would also allow the storage of content at high resolutions. Royalties that would be paid to On2 Technologies for the use of the video technology was relatively low, around $2 (considerably lower than using MPEG-2)
For audio, the format would use an audio codec called "EAC" from Coding Technologies. EAC stands for Enhanced Audio Codec. It supports mono, 2.0 stereo audio and 5.1 surround. The Chinese Government backed the development of the format, as it would reduce the country's tech industry's dependence on technology from foreign countries and lower the costs for manufacturers.
A legal dispute broke out between Beijing E-World and On2 Technologies over claims the On2 was not being properly paid. However, On2's claims were dismissed by an arbitrator. Since this legal dispute there hasn't been any major developments with the EVD format.
