MPEG-3 is concentrated on HDTV. It was originally designed for applications with picture sizes of up to 1920 * 1080 and bitrates of 20 - 40 Mbit/s. It was later discovered that HDTV could be done with MPEG-2 after some fine tuning. This group is not active any more because of the failure of HDTV and the work mainly done by MPEG 2 group. The HDTV is included in the "MPEG-2 High-1440 Level" - specification.
The MPEG-4 group started in Bruxelles in September 1994 and it is developing a low bitrate standard of video and audio for use in mobile environment (GSM), multimedia electronic mail, remote sensing, electronic newspapers, videophone, games, sign language captioning and various other applications.
The bitrate is from 4.8 up to 64 kbit/s. The picture size is up to 176 * 144 and up to 10 frames/sec. The very low bitrate means that new compression techniques, utilizing e.g. morphing and fractals, will have to be developed. The official proposed standard is supposed to be ready in late 1998.
