MPEG-4 Part 20

Last updated

MPEG-4 Part 20, or MPEG-4 Lightweight Application Scene Representation (LASeR) is a rich media standard dedicated to the mobile, embedded and consumer electronics industries specified by the MPEG standardization group. LASeR is based on SVG Tiny and adds methods for sending dynamic updates and a binary compression format.

Contents

The ISO document defining LASeR is ISO 14496-20, Lightweight Application Scene Representation (LASeR) and Simple Aggregation Format (SAF). [1]

Introduction

MPEG-4 Part 20 is a specification designed for representing and delivering rich-media services to resource-constrained devices such as mobile phones. It defines two binary formats: LASeR, Lightweight Application Scene Representation, a binary format for encoding 2D scenes, including vector graphics, and timed modifications of the scene; and SAF, Simple Aggregation Format, a binary format for aggregating in a single stream LASeR content with audio/video streams.

LASeR, a binary format for representing rich-media services content

The LASeR specification has been designed to allow the efficient representation of 2D scenes describing rich-media services for constraint devices. A rich-media service is a dynamic and interactive presentation comprising 2D vector graphics, images, text and audiovisual material. The representation of such a presentation includes describing the spatial and temporal organization of its different elements as well as its possible interactions and animations.

MPEG evaluated the state-of-art technologies in the field of composition coding. Seeing that none were satisfactory for constraint devices like mobiles phones, MPEG decided to create the LASeR standard. The LASeR requirements included compression efficiency, code and memory footprint. The LASeR standard fulfills these requirements by building upon the existing Scalable Vector Graphics (SVG) format defined by the World Wide Web Consortium and particularly on its Tiny profile already adopted in the mobile industry. LASeR complements SVG by defining a small set of compatible key extensions tuned according to the requirements. These key extensions permit among others: the frame-accurate synchronization of the scene with the audio-visual elements, the streaming and efficient compression of SVG content. The workflow of LASeR content from creation based on SVG to consumption is depicted in Figure 1.

The streaming capability of LASeR is a benefit of the concept of LASeR stream, inspired from the MPEG-4 BIFS standard. A LASeR stream is the concatenation of an initial scene and the timed modifications of it, which can be sent in a streaming mode from a server to a client in a timed manner.

Efficient compression improves delivery and decoding times, as well as storage size and is achieved by a compact binary representation of the SVG scene tree. This compact representation is tailored for the efficient compression of SVG content. Specific encoding techniques have been designed for simple yet efficient encoding of SVG specific data.

SAF, the aggregation of LASeR and audiovisual material

The delivery of Rich Media content to constraint devices is a challenging task which consists in delivering the representation of the presentation along with all the audiovisual material used in it. Efficient delivery, especially on mobile low bandwidth networks, requires reactivity and fluidity.

The SAF specification defines tools to enable the transport of LASeR content along with its attached audiovisual material according to these requirements. The SAF specification defines a binary format for a SAF stream, made of a LASeR stream with any type of media stream. SAF streams are low overhead multiplexed streams which can be successfully delivered using any delivery mechanism: download-and-play, progressive download, streaming or broadcasting. To achieve reactivity, the SAF specification defines the concept of cache unit which allows sending in advance sub-content which will be used later on in the presentation.

SAF streams may be: [2]

Target applications

Mobile interactive portals (as depicted in Figure 1), Mobile TV (over 3G, DVB-H, DMB, …), 2D cartoons, interactive vector graphics maps, 2D widgets, etc.

Related Research Articles

<span class="mw-page-title-main">Moving Picture Experts Group</span> Alliance of working groups to set standards for multimedia coding

The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and file formats for various applications. Together with JPEG, MPEG is organized under ISO/IEC JTC 1/SC 29 – Coding of audio, picture, multimedia and hypermedia information.

MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496 – Coding of audio-visual objects. Uses of MPEG-4 include compression of audiovisual data for Internet video and CD distribution, voice and broadcast television applications. The MPEG-4 standard was developed by a group led by Touradj Ebrahimi and Fernando Pereira.

Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium since 1999.

OpenType is a format for scalable computer fonts. Derived from TrueType, it retains TrueType's basic structure but adds many intricate data structures for describing typographic behavior. OpenType is a registered trademark of Microsoft Corporation.

Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves higher sound quality than MP3 encoders at the same bit rate.

X3D is a set of royalty-free ISO/IEC standards for declaratively representing 3D computer graphics. X3D includes multiple graphics file formats, programming-language API definitions, and run-time specifications for both delivery and integration of interactive network-capable 3D data. X3D version 4.0 has been approved by Web3D Consortium, and is under final review by ISO/IEC as a revised International Standard (IS).

<span class="mw-page-title-main">Advanced Video Coding</span> Most widely used standard for video compression

Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 Part 10, is a video compression standard based on block-oriented, motion-compensated coding. It is by far the most commonly used format for the recording, compression, and distribution of video content, used by 91% of video industry developers as of September 2019. It supports a maximum resolution of 8K UHD.

MPEG-4 Part 3 or MPEG-4 Audio is the third part of the ISO/IEC MPEG-4 international standard developed by Moving Picture Experts Group. It specifies audio coding methods. The first version of ISO/IEC 14496-3 was published in 1999.

Computer Graphics Metafile (CGM) is a free and open international standard file format for 2D vector graphics, raster graphics, and text, and is defined by ISO/IEC 8632.

<span class="mw-page-title-main">High-Efficiency Advanced Audio Coding</span> Audio codec

High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio defined as an MPEG-4 Audio profile in ISO/IEC 14496–3. It is an extension of Low Complexity AAC (AAC-LC) optimized for low-bitrate applications such as streaming audio. The usage profile HE-AAC v1 uses spectral band replication (SBR) to enhance the modified discrete cosine transform (MDCT) compression efficiency in the frequency domain. The usage profile HE-AAC v2 couples SBR with Parametric Stereo (PS) to further enhance the compression efficiency of stereo signals.

The Extensible MPEG-4 Textual Format (XMT) is a high-level, XML-based file format for storing MPEG-4 data in a way suitable for further editing. In contrast, the more common MPEG-4 Part 14 (MP4) format is less flexible and used for distributing finished content.

MPEG-4 Part 11Scene description and application engine was published as ISO/IEC 14496-11 in 2005. MPEG-4 Part 11 is also known as BIFS, XMT, MPEG-J. It defines:

An image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may be compressed or uncompressed. If the data is compressed, it may be done so using lossy compression or lossless compression. For graphic design applications, vector formats are often used. Some image file formats support transparency.

QuickTime File Format (QTFF) is a computer file format used natively by the QuickTime framework.

MPEG-4 Audio Lossless Coding, also known as MPEG-4 ALS, is an extension to the MPEG-4 Part 3 audio standard to allow lossless audio compression. The extension was finalized in December 2005 and published as ISO/IEC 14496-3:2005/Amd 2:2006 in 2006. The latest description of MPEG-4 ALS was published as subpart 11 of the MPEG-4 Audio standard in December 2019.

<span class="mw-page-title-main">MP4 file format</span> Digital format for storing video and audio

MPEG-4 Part 14 or MP4 is a digital multimedia container format most commonly used to store video and audio, but it can also be used to store other data such as subtitles and still images. Like most modern container formats, it allows streaming over the Internet. The only filename extension for MPEG-4 Part 14 files as defined by the specification is .mp4. MPEG-4 Part 14 is a standard specified as a part of MPEG-4.

BiM is an international standard defining a generic binary format for encoding XML documents.

<span class="mw-page-title-main">GPAC Project on Advanced Content</span>

GPAC Project on Advanced Content is an implementation of the MPEG-4 Systems standard written in ANSI C. GPAC provides tools for media playback, vector graphics and 3D rendering, MPEG-4 authoring and distribution.

The ISO base media file format (ISOBMFF) is a container file format that defines a general structure for files that contain time-based multimedia data such as video and audio. It is standardized in ISO/IEC 14496-12, a.k.a. MPEG-4 Part 12, and was formerly also published as ISO/IEC 15444-12, a.k.a. JPEG 2000 Part 12.

References

  1. ↑ ISO. "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. Retrieved 2009-10-30.
  2. ↑ "Technical Overview". mpeg-laser.org. Archived from the original on 2010-09-26. Retrieved 2010-04-11.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.