Overview
ISO/IEC 14496-2:2004 - Part 2: Visual defines the coded representation and decoding of visual information for object‑based video. The standard specifies video coding tools, bitstream syntax and semantics, and the complete decoding process for a wide range of visual objects - from rectangular pictures to arbitrarily shaped video objects, still textures, face/body animation, and animated 2D warping meshes. The Visual specification covers bitstream structure and decoder behavior; it does not mandate encoder implementations.
Key Topics
- Visual bitstream syntax and semantics: detailed definitions of bitstream elements, their meaning and parsing rules for decoder implementations.
- Object-based coding: support for video objects and Video Object Planes (VOPs) enabling content-based access and manipulation (seek, composition).
- Shape, texture and motion coding: representation of object shape, texture and motion information to exploit spatial and temporal redundancy.
- Scalable bitstreams & error resilience: tools and profiles to create scalable layered streams (base + enhancements) and mechanisms for robust decoding over lossy channels.
- Specialized object types:
- Still texture mapping into scenes
- Face & Body Animation (FBA) using Facial/Body Definition and Animation Parameters (FDP/FAP, BDP/BAP) for low-bandwidth animation
- 2D warping grid animation (uniform and irregular topologies) and mesh object decoding
- Decoding processes: full decoder algorithms for video, interlaced content, sprites, generalized scalability, FGS (fine-grain scalability) and studio profiles.
- Profiles & levels: defined subsets and constraints to ensure interoperability across devices and application classes.
- Normative annexes: coding transforms, VLCs/arithmetic decoding, FBA tables, Video Buffering Verifier (VBV) and profile/level restrictions.
Applications
ISO/IEC 14496-2:2004 is intended for applications that need interoperable, object-aware visual coding across networks and storage:
- Internet multimedia and streaming services
- Interactive video games and multimedia authoring
- Videoconferencing, videophone and interpersonal communications
- Interactive and optical storage media distribution
- Wireless multimedia and low-bandwidth face animation for broadcast/interactive systems
- Surveillance systems and networked video databases
Practical benefits include object-level access and editing, scalable delivery (adaptation to bitrate/resolution), bandwidth‑efficient face/body animation, and decoder interoperability.
Who should use it
- Codec implementers and decoder developers
- Device manufacturers (set-top boxes, mobile terminals)
- Media/file format vendors and content distributors
- Broadcast and streaming system architects
- Researchers and standards engineers building interoperable multimedia systems
Related standards
Relevant parts of the ISO/IEC 14496 family include:
- Part 1: Systems (stream composition and delivery)
- Part 3: Audio
- Part 10: Advanced Video Coding (AVC)
- Part 12 / 14: ISO base media file format / MP4 file format
Keywords: ISO/IEC 14496-2:2004, visual bitstream, video object, VOP, scalable bitstreams, error-resilient encoding, face and body animation, 2D warping grids, bitstream syntax, decoding process, profiles and levels.
