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ISO/IEC JTC 1/SC 29/WG 11

CODING OF MOVING PICTURES AND AUDIO

ISO/IEC JTC 1/SC 29/WG 11 N6832

October 2004, Palma de Mallorca, ES

Source:

Requirements

Title:

MPEG-A Multimedia Application Format Overview and Requirements (v.2)

Editor:

Wo Chang

MPEG-A Multimedia Application Format Overview

Table of Contents

1      Introduction.

2      Requirements for Multimedia Application Formats in general.

2.1        Requirements for Starting a new MAF

3      Requirements for Individual MAFs.

3.1        3on4

3.2        Jon4.

4      Technical Description of MAFs under Development.

4.1        3on4.

4.2        Jon4.

5      References.

1                  Introduction

This document presents an overview of MPEG’s Multimedia Application Formats (MAF), which provide the framework for integration of elements from several MPEG standards into a single specification that is suitable for specific, but widely usable applications. Typically, MAFs specify how to combine metadata with timed media information for a presentation in a well-defined format that facilitates interchange, management, editing, and presentation of the media. The presentation may be ‘local’ to the system or may be via a network or other stream delivery mechanism. 

The goal of this overview is to explain the general concepts behind the Multimedia Application Formats, their requirements, and to explain which ones are under development in MPEG

Note: Which file format to use (MPEG-4 or MPEG-21) is subject to an ongoing discussion

2                  Requirements for Multimedia Application Formats in general

MAF specifications shall integrate elements from different MPEG standards into a single specification that is useful for specific but very widely used applications. Examples are delivering music, pictures or home videos. MAF specifications may use elements from MPEG-1, MPEG-2, MPEG-4, MPEG-7 and MPEG-21. Typically, MAF specifications include:

MAFs may specify use of:

MAF Specifications can contain elements from all existing MPEG Standards. MAF specification shall use existing Profiles whenever practical, and at a certain Level if applicable. In exceptional circumstances, non-Profile tool sets may be used.

MAF Specifications shall fully specify the elements that are used from the MPEG standards (and other standards if applicable) with all their constraints, so that full interoperability can be achieved.

MAF Specifications shall specify a core metadata set to be supported by any implementation of that MAF, and may enable private extensions.

MAF Specifications shall be made available in the form of text and Reference Software. The Reference SW shall enable a rapid uptake of the MAF in question.

2.1           Requirements for Starting a new MAF

3                  Requirements for Individual MAFs

3.1           3on4

The 3on4 MAF shall specify a simple and uniform way to carry MP3 content in an MPEG version of the ISO Media File Format augmented by simple MPEG-7 metadata.  Specific MPEG-7 Metadata shall represent data commonly expressed in IDv3 as follows:

3.2           Jon4

The Jon4 MAF shall specify a simple and uniform way to carry JPEG pictures in an MPEG-4/21 File Format augmented by simple MPEG-7 metadata.

The MPEG-7 Metadata shall represent data commonly expressed in EXIF.  Specific MPEG-7 Metadata shall represent data commonly expressed in EXIF as follows:

4                  Technical Description of MAFs under Development

MAF uses the ISO/IEC MPEG-4/21 File Format to provide a \format for management and presentation of the media.

Figure- SEQ Figure \* ARABIC 1: Example of a simple ISO file used for interchange, containing two streams

MP21FF is derived from the ISO Base Media File Format (ISO/BMFF).  It uses object-oriented as its structure shown in Figure-1 so that a file can be decomposed into constituent objects very simply, and the structure of the objects inferred directly from their type. The file format is designed to be independent of any particular network protocol while enabling efficient support for them in general.

Static metadata in the ISO/BMFF File Format is provided in the form of ‘user data boxes – udta’ as shown in Figure-2. Only copyright is defined in the current specification, but other ‘udta’ boxes may be defined using unique user id extension mechanism (UUID). The scope of ‘udta’ boxes applies to the entire presentation or to the entire stream.

The ISO/BMFF also provides support in the form of ‘meta’ boxes at the File, Presentation and Stream level. This allows support for static (un-timed) meta-data. Figure-3 illustrates the use of un-timed MPEG-7 Metadata in binary and text form, and the use of a code-point for other ID3 Metadata.

 

Figure- SEQ Figure \* ARABIC 3: Support of Static un-timed Metadata in MP4 Files

4.1           3on4

MPEG-1/2 Audio Layer III, also known as MP3, is one of the most widely used MPEG standards.  Currently, the ID3, which was created by simply appending simple metadata tags such as Artist, Album, Song Title, etc. at the end of the MP3 and turned out to be very positive thing to do since they provide useful content description about the music clip. 

Since that time MPEG has developed a number of standards, all of which strive to serve the needs of consumers and industry. Among those are MPEG-4, a next-generation suite of standards for media compression, and MPEG-7, a suite of standards for meta-data representation. MPEG-4 specifies what MPEG expects to be another very successful specification, the MPEG-4 File Format, while MPEG-7 specifies not only signal-derived meta-data, but also archival meta-data such as Artist, Album and Song Title.

As such, MPEG-4 and MPEG-7 represent an ideal environment to support the current “MP3 music library” user experience, and, moreover, to extend that experience in new directions.

4.2           Jon4

Digital Camera is one of the most popular consumer digital devices, with estimates showing over 100 million units sold worldwide (2001). In the next two years the sales of digital cameras are expected to overtake sales of their analogue counterparts in Japan, US and Europe. JPEG is the common data format used in the great majority of the cameras. 

Consumers appreciate the ease with which digital photographs can be taken, copied, post-processed and shared. However, only few months use of a digital camera will typically generate a library with few thousands of digital photographs.  Performing many common tasks, such as search for photographs of interest, becomes a tedious and time-consuming exercise. As a consequence, there is a growing demand for provision of suitable metadata, such as information about the photo content (e.g. the subject being photographed), author, shoot location, imaging parameters, etc. Such metadata needs to be stored in a standardized format, which can be easily interchanged between various digital devices.

The need to store metadata generated early in the acquisition process has been reflected in the EXIF standard, which is commonly adopted by the camera manufacturers. However, while very useful, the EXIF standard is limited in scope to basic “acquisition” related information and does not support more advanced metadata.

MPEG has developed standard (MPEG-7) defining rich metadata descriptions for still images, audio and also provides associated systems tools (file formats, etc).

As such, MPEG-7 and MPEG-4 file format represent an ideal environment to support the current “Digital Photos Library” user experience, and, moreover, to extend that experience in new directions.

5                  References

1.      ISO/IEC 14496-12:2003   Information technology -- Coding of audio-visual objects -- Part 12: ISO Base Media File Format (available in English only)

2.      http://www.id3.org/id3v1.html

3.      http://www.3gpp.org/

4.      Exchangeable image file format for digital still cameras: EXIF Version2.2, JEITA CP-3451, Standard of Japan Electronics and Information Technology Industries Association

5.      ISO/IEC 11172-3:1993   Information technology -- Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s -- Part 3: Audio

6.      ISO/IEC 11172-3:1993/Cor 1:1996   (available in English only)

7.      ISO/IEC 13818-3:1998   Information technology -- Generic coding of moving pictures and associated audio information -- Part 3: Audio (available in English only)

8.      ISO/IEC 14496-3:2001   Information technology -- Coding of audio-visual objects -- Part 3: Audio (available in English only)

9.      ISO/IEC 14496-3:2001/Cor 1:2002   (available in English only)

10.  ISO/IEC 14496-3:2001/Amd 3 (MP3onMP4)

11.  ISO/IEC 14496-14:2003   Information technology -- Coding of audio-visual objects -- Part 14: MPEG-4 File Format (available in English only)

12.  ISO/IEC TR 15938-8:2002   Information technology -- Multimedia content description interface -- Part 8: Extraction and use of MPEG-7 descriptions (available in English only)

13.  ISO/IEC 15938-9:CD   Information technology -- Multimedia content description interface -- Part 9: Profiles and levels (available in English only)