Section Two: Video Encoding Standards
MPEG-4 (ISO/IEC 14496 MPEG-4)

MPEG-4 ISO/IEC 14496 MPEG-4, the latest encoding standard from MPEG, was finalized in October 1998 and should be ratified as a standard in the first half of 1999. MPEG-4 arose from a need to have a scalable standard supporting a wide bandwidth range from streaming video at less than 64 Kbit/sec, suitable for Internet applications, to approximately 4 Mbit/sec for higher-bandwidth video needs. MPEG-4 also arose from a desire, as digital encoding matures, to advance beyond simple conversion and compression to object recognition and encoding, as well as the provision of synchronized text and metadata tracks, to create a digital file that carries a meaning greater than the sum of its individual parts.

MPEG-4 supports both progressive and interlaced video encoding. The standard is object-based, coding multiple video object planes into images of arbitrary shape. Successive video object planes (VOPs) belonging to the same object in the same scene are encoded as video objects. MPEG-4 supports both natural ("analog") and synthetic ("computer-generated") data coding. Some VRML technology is incorporated to encode dimensionality.

MPEG-4 compression provides temporal scalability utilizing object recognition, providing higher compression for background objects, such as trees and scenery, and lower compression for foreground objects, such as an actor or speaker-much as the human eye filters information by focusing on the most significant object in view, such as the other party in a conversation. Object encoding provides great potential for object or visual recognition indexing, based on discrete objects within a frame rather than requiring a separate text-based or storyboard indexing database. In addition, MPEG-4 provides a synchronized text tract for courseware development and a synchronized metadata track for indexing and access at the frame level.