Most recent

ISO/IEC 14496-20:2008

Information technology - Coding of audio-visual objects - Part 20: Lightweight Application Scene Representation (LASeR) and Simple Aggregation Format (SAF)


ISO/IEC 14496-20:2008 defines a scene description format (LASeR) and an aggregation format (SAF) respectively suitable for representing and delivering rich-media services to resource-constrained devices such as mobile phones.

LASeR aims at fulfilling all the requirements of rich-media services at the scene description level. LASeR supports:

  • an optimized set of objects inherited from SVG to describe rich-media scenes,
  • a small set of key compatible extensions over SVG,
  • the ability to encode and transmit a LASeR stream and then reconstruct SVG content,
  • dynamic updating of the scene to achieve a reactive, smooth and continuous service,
  • simple yet efficient compression to improve delivery and parsing times, as well as storage size, one of the design goals being to allow both for a direct implementation of the SDL as documented, as well as for a decoder compliant with ISO/IEC 23001-1 to decode the LASeR bitstream,
  • an efficient interface with audio and visual streams with frame-accurate synchronization,
  • use of any font format, including the OpenType industry standard, and
  • easy conversion from other popular rich-media formats in order to leverage existing content and developer communities.

Technology selection criteria for LASeR included compression efficiency, but also code and memory footprint and performance. Other aims included: scalability, adaptability to the user context, extensibility of the format, ability to define small profiles, feasibility of a J2ME implementation, error resilience and safety of implementations.

SAF aims at fulfilling all the requirements of rich-media services at the interface between media/scene description and existing transport protocols:

  • simple aggregation of any type of stream,
  • signaling of MPEG and non-MPEG streams,
  • optimized packet headers for bandwidth-limited networks,
  • easy mapping to popular streaming formats,
  • cache management capability, and
  • extensibility.

SAF has been designed to complement LASeR for simple, interactive services, bringing:

  • efficient and dynamic packaging to cope with high latency networks,
  • media interleaving, and
  • synchronization support with a very low overhead.

ISO/IEC 14496-20:2008 defines the usage of SAF for LASeR content; however, LASeR can be used independently from SAF.


CONTENT PROVIDER
International Organization for Standardization [iso]

Included in Packages
This standard is not included in any packages.
Document History