MPEG-4 Industry Forum announced

MP4 Files optimized for streaming; tests confirm quality MPEG-4 Video

Vancouver, BC, Canada, July 17, 1999 – At the 48th MPEG meeting in Vancouver, BC, Canada, prospective members of the MPEG-4 Industry Forum (M4IF) met for the first time. The Forum, which will be created outside ISO/IEC MPEG, aims at bootstrapping the adoption of the MPEG-4 standard, which is now final in Version 1.

Extensive subjective testing has demonstrated the excellent quality of the MPEG-4 Video coding. At bitrates below 1 Mbit, bitrate savings of about 30%, sometimes up to 50%, can be achieved over MPEG-1. A decision was taken to add normative ‘hint tracks’ to the MP4 file format, for streaming over commonly used transport layers (UDP, RTP and MPEG-2 Transport Stream). Part 5 of the MPEG-4 standard, the software implementation, is now ready, and will, after a final two-month ballot, be made available. This part gives a complete implementation of MPEG-4 in source code, to be used free from copyright for implementations that conform to the standard. MPEG-4’s very high quality extension, tentatively called ‘Simple Studio Profile’, was promoted to Working Draft. It supports arbitrary shaped objects at bitrates up to 600 Mbit/s. MPEG is working on recommendations for displaying MPEG-2 encoded material on progressive displays. To develop a part of the MPEG-7 Multimedia Description standard, a new ‘Multimedia Description Scheme’ group was created in MPEG. Prof. Philippe Salembier of the Technical University of Catalonia (UPC), Spain, will chair the new group.

The 48th MPEG meeting was held at the kind invitation of the Canadian National Body, and hosted by the University of British Columbia and Image Power, Inc.

Version 2 of MPEG-4, a backward compatible extension of the existing MPEG-4 standard, was promoted to Final Committee Draft. The next step to Final Draft International Standard will happen in December, and after that the text of Version 2 is fixed. MPEG-4 Version 2 adds new Visual profiles that have demonstrated better coding efficiency, have more scalability options and have increased error resiliency and real time performance. MPEG-4 V.2 Audio also adds low delay and error resiliency. Part 5 of MPEG-4 Version q was also finalized.

Studies are ongoing for optimizing MPEG-2 quality on progressive displays. The proposed MPEG-4 Simple Studio Profile (tentative name), with bitrates up 600 Mbit, was promoted to Working Draft. The Simple Studio Profile employs only I frames (intra-coded Video Object Planes -VOP’s- in MPEG-4 terminology), with the possibility to attach multiple shape planes to each VOP. New people eager to implement mpeg-4

The initiative for an MPEG-4 Industry Forum was well received. "Estimates for the investment in the development of MPEG-4 range from $300 to $500 million. Everyone acknowledges that the standard has enormous potential, but at the moment, companies are basically waiting to see what others do. And if you do want to implement the standard, good information is sometimes hard to get. The idea is to make just that little extra bit of effort that is necessary to make MPEG-4 fly", said Rob Koenen, chair of MPEG’s Requirements group and initiator of the forum. Koenen added that the forum was started as a separate organization because a standards committee is not the right place for commercial actions. This first step will be setting up a central site with information, as good information about the standard is currently hard to get. The site should also contain demonstrations, MPEG-4 content, and the Forum is trying to make free software available.

An impressive demonstration was shown of the power of MPEG-4’s ‘lower layers’: Systems (providing synchronization) and DMIF (an interface to transport systems). An audio stream pulled from a local storage was played lip-sync with a video stream pushed from a remote server. Severe transmission error conditions affecting the video data, including a temporary break-down of the link, could not break the synchronization. Guido Franceschini of CSELT, It, parting chairman of MPEG’s delivery group, said that this was a good demonstration of the power of MPEG-4: it is more than just best effort. "We really want to be able to guarantee the quality of multimedia content when it plays on your device - regardless of the delivery medium", said Franceschini.

Video works on MPEG-2 on non-interlaced displays

A study of the MPEG-2 specification was initiated to assess encoding and decoding issues surrounding the display of content on non-interlaced displays. The conclusion of this work will result in improved visual quality of video on existing non-interlaced displays including computer monitors, flat panels, and active mirror projection systems. A number of editing and encoding recommendations have been issued to various organizations, including SMPTE, EBU, DVB and the DVD consortium. This study will continue in cooperation with these organizations in the form of experiments to measure the risks and benefits of several proposed solutions. The proposals may recommend further changes in current encoding and editing practices, as well as the addition of more descriptive data.

Audio adds low delay, error robustness

At this meeting MPEG-4 Audio Version 2, progressed to Final Proposed Draft Amendment, the equivalent of Final Committee Draft. MPEG-4 Version 2 contains coding tools that allow low delay audio coding, fine grain scalability of audio compression and very low bit rate parametric audio coding. The parametric coding tools add two new features to the Version 2 tools, namely 4 kb/s variable bitrate for the Harmonic Vector eXcitation Coder and silence compression for the Code Excited Linear Prediction coder. Finally, they contain tools that permit error resilience and error protection, thus supporting applications over error-prone channels.

The error robustness tools, an innovation within MPEG audio, consist of a number of components. Firstly, bits are reordered so that errors have minimum subjective impact. Secondly, the most important parts of the bitstream receive the strongest protection and thirdly, several state-of-the-art error detection and correction techniques are supported, while each can be configured with varying levels of error protection capability.

Subjective testing of the new tools is underway, and the results of these tests should be available at the 50th MPEG meeting in December. The test will, among other issues, measure the effectiveness of the error protection tools.

Three MPEG-7 audio experiments are planned for the coming months, meant to develop schemes for representing the output of automatic speech recognition systems, identifying musical instruments in a complex musical scene, and representing and automatically retrieving melodies.

Systems readies file format for direct streaming.

An important element was added to the MPEG-4 file format MP4. MP4 will become streamable thanks to so-called pre-defined "hint tracks". These are specified for the more relevant transport mechanisms: UDP, RTP, MPEG-2 Transport Stream. This means that anyone can create MP4 files that can be streamed in an efficient way. The specification of carriage of MPEG-4 on MPEG-2 transport streams and on IP networks was included in the Final Committee Draft. MPEG-4 Scene description gets new compelling functionality in Version 2: Body Animation and advanced spatialization of sounds are now included. Version 2 also incorporates interactive and intelligent content with "MPEG-lets", or MPEG-J Java applets.

Multimedia Description Schemes group created

At this meeting, the new Multimedia Description Schemes Group was established. It will develop international standards for schemes that describe multimedia content data structures and related information. The first activity of the group was to issue an updated definition of the "Generic Audio Visual Description Scheme for MPEG-7". This is a highly structured organization of MPEG-7 data, with which multimedia content can be described. A close link with the Society of Motion Picture and Television Engineers (SMPTE) and the European Broadcasting Union (EBU) will be pursued, with the aim of jointly working on MPEG-7.

Tests indicate the excellent quality of MPEG-4 Video

Five tests were conducted giving an indication of the excellent quality provided by MPEG-4. Thirteen tests, involving more than 130 subjects, were conducted in six different test sites (CCETT, Fr; CSELT, It; IRT, De; FUB, It; NHK, Jp; NTT-AT, Jp). The tests show a clear superiority of MPEG-4 compared to MPEG-1 at the medium bit rate coding conditions (384 to 768 kbit/s), independent of content criticality. For some tested items, bit savings were around 30%.

Other verification tests showed that in most conditions, the temporal scalability (base plus enhancement layer) in Core Profile gives the same overall quality as single layer coding. For higher bitrates, single layer exceeds scalable quality, but the difference is small. In all cases, the quality given by base plus enhancement layer is clearly better than base layer quality alone.

Subjective tests with the Advanced Real Time Simple Profile show that at 64 kbit/s, it outperforms the already effective Simple Profile operating at 96 kbit/s, and at 96 kbit/s it performs equally well as the Simple profile at 128 kbit/s. (The Simple profile already compares favorably to other, existing systems.)

The Advanced Real Time Simple Profile is designed for real-time usage, exploiting the fact that the decoder can send signals back to the encoder. It uses ‘Dynamic Resolution Conversion’, a technique that adapts the resolution to the video content and to circumstances in real-time. These tests also show the superior performance under severe error conditions. In ‘critical’ error conditions (10-3 bit error rate, in 10 ms bursts) error-related artifacts were hardly noticeable, while in ‘very critical’ error conditions (same error rate but more spread over the bitstream) recovery was very fast.

Further information

Future MPEG meetings will be held in Melbourne, Australia (October 1999), Maui, Hawaii (December 1999), the Netherlands (March 2000), China (July 2000), France (October 1999)

For further information about MPEG, please contact:

Dr. Leonardo Chiariglione, (Convenor of MPEG)
CSELT
Via G. Reiss Romoli, 274
I-10148 Torino, ITALY
Tel.: +39 11 228 6120; Fax: +39 11 228 6299
Email: leonardo.chiariglione@cselt.it

or

This press release and much other MPEG-related information can be found on the MPEG homepage:

http://www.cselt.it/mpeg

The MPEG homepage has links to other MPEG pages, which are maintained by some of the subgroups. It also contains links to public documents that are freely available for download to non-MPEG members.

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