Five Japanese Companies Proposal Wins Industry Acceptance for MPEG-4 Realtime Transport Protocol Standardization

10 April, 2001

Toshiba Corporation
NEC Corporation
Oki Electric Industry Co., Ltd.
Matsushita Electric Industrial Co., Ltd.
Nippon Telegraph and Telephone Corporation

Tokyo--Five Japanese companies today announced that their jointly proposed format for transferring MPEG-4 streams over the Internet has now been accepted by three key organizations that promote development of Internet protocols. Toshiba Corporation, NEC Corporation, Oki Electric Industry Co., Ltd., Matsushita Electric Industrial Co., Ltd. and Nippon Telegraph and Telephone Corporation confirmed that the 3G Partnership Project (3G-PP) has joined the Internet Engineering Task Force (IETF) and the International Telecommunications Union (ITU) in supporting the standard, a move expected to bring uniformity to MPEG-4 content on the Internet and delivered over mobile networks.

The new transfer format is based on the Real-time Transport Protocol (RTP) standardized by IETF in 1996, rather than TCP/IP, which IP networks typically use for their transfer protocol. However, if TCP/IP detects any loss of data during transmission, it automatically retransmits it. The practical result is delays in data transfers that are unacceptable for real-time transfers of audio and video signals, particularly in streaming video and audio.

RTP is functionality suited for carrying real-time content as it provides support for applications with real-time properties, including timing reconstruction and loss detection. RTP uses UDP/IP, which doesn't have resending process characteristics. It places RTP headers in each packet that contains a timestamp, enabling synchronized display of audio and video signals at receivers, and sequence numbers to support packet loss detection. These characteristics enable timely data delivery with less degradation. RTP is widely used for audio and video distribution over the Internet, Internet tele-conferencing systems and Voice over IP (VoIP).

RTP is designed to define payload formats for each audio-video medium transferred. This is the area where the solution proposed by the five Japanese companies has been accepted for MPEG-4 audio and video signals.

A characteristic of the RTP payload format for MPEG-4 video is the provision of MPEG-4 error resiliency tools, to reduce packet loss. In order to improve transmission error resiliency, the MPEG-4 coding exploits the video packet approach within MPEG-4's error resilience tools, which subdivides the picture frames while coding. MPEG-4 also employs a technique called Header Extension Code (HEC), a 1-bit field introduced in each video packet. If this bit is set, the important header information that describes the video frame is repeated in the video packet. By checking this header information in the video packets against the information received at the beginning of the video frame, the decoder can ascertain if the video frame header is received correctly. If the video frame is corrupted, the decoder can still decode the rest of the data in the video frame using the header information that is repeated in the video packets.

The RTP payload format for MPEG-4 audio is an adoption of Low-overhead Audio Transport Multiplexing (LATM) technology, which effectively transfers multiple audio frames with a very low overhead.

It also offers an advantage in the comparative simplicity of the RTP format, in that audio and video streams are directly mapped onto the RTP packet and do not require specific headers or multiplexing.

The five companies held interoperability tests on the transfer format and confirmed its stability and reliability. The format was adopted by the IETF as the RTP payload format for MPEG-4 audio and video signals, by the 3G Partnership Project (3G-PP) in its packet switched multimedia streaming service standard for 3G mobile phones, and by the ITU Telecommunications Standardization Sector (ITU-T) in its recommendation for multimedia conferencing over packet-based networks such as LANs and the Internet.

The standardization will greatly contribute to promoting audio-video distribution on the Internet and in bringing the distribution service to next-generation cellular phones. It is especially important for such applications as Internet telephony and cellular telephony, where a high level of interoperability is required.

About Toshiba Corporation:

Toshiba Corporation is a leader in information and communications systems, electronic components, consumer products and power systems. The company's integration of these wide-ranging capabilities assures its position as an innovator in advanced components, products and systems. Its next-generation MPEG-4 and wireless communications technologies have assured Toshiba's leadership in W-CDMA development in Japan, where it is the technology development partner of NTT DoCoMo--the country's leading mobile service provider. In fiscal 1999, Toshiba had 191,000 employees worldwide and recorded sales of 5,749 billion yen (approx. US$54 billion). Visit Toshiba's web site at

About NEC Corporation:

NEC Corporation (NASDAQ: NIPNY) (FTSE: 6701q.l) (TSE: 6701) is a leading provider of Internet solutions, dedicated to meeting the specialized needs of its customers in the key computer, network and electron device fields through its three market-focused in-house companies: NEC Solutions, NEC Networks and NEC Electron Devices. NEC Corporation, with its in-house companies, employs more than 150,000 people worldwide and saw net sales of 4,991 billion yen (approx. US$48 billion) in fiscal year 1999-2000. For further information, please visit the NEC home page at:

About Oki Electric Industry Co., Ltd.:

Founded more than a century ago in 1881, Oki Electric Industry Co., Ltd. is Japan's first telecommunications manufacturer headquartered in Tokyo, Japan. With more than 21,000 employees worldwide, Oki Electric provides customers with top-notch products and technologies for telecommunication systems, information systems and electronic devices. Visit Oki's global web site at

About Matsushita Electric:

Matsushita Electric Industrial Co., Ltd. (NYSE: MC), best known for its Panasonic brand name, is a worldwide leader in the development and manufacture of electronics products for a wide range of consumer, business, and industrial needs. Matsushita is playing a major role in the standardization bodies such as MPEG and 3G-PP, and holding a leading position in the marketing of wireless communication terminals, MPEG-4 LSI and so on. Based in Osaka, Japan, the company recorded consolidated sales of US$68.9 billion for the fiscal year ended March 31, 2000. For further information, please visit our web site at

About Nippon Telegraph and Telephone Corporation:

Nippon Telegraph and Telephone Corporation (NTT) implemented a major reorganization and was reborn in July 1999 as the new NTT Group. NTT Group has put forward the slogan "Global Information Distribution Corporate Group" as being representative of its policy for business activities, which are aimed at the creation of a rich "information distribution" market where the flow of information will give birth to new value. The goal of the Group is to work toward creating new opportunities for "Information distribution" business in a variety of forms, not limited to the traditional telecommunications field but also including such efforts as the construction of platforms to safely and efficiently distribute videos and other types of content. NTT Group has 224,000 employees and annual sales of 10,421 billion yen (approx. US$97 billion). Please visit NTT home page at

Press Contacts:

Toshiba Corporation:
Midori Suzuki
Corporate Communications Office
Tel: +81-3-3457-2105
Fax: +81-3-5444-9202

NEC Corporation:
Daniel Mathieson
Corporate Communications Division, Public Relations
Tel: +81-3-3798-6511
Fax: +81-3-3457-7249

Oki Electric Industry Co., Ltd.:
Akira Miyakoshi
Public Relations Division
Tel: +81-3-3580-8950
Fax: +81-3-3581-5522

Matsushita Electric Industrial Co., Ltd.:
Yoshihiro Kitadeya,
International Publicity, Osaka
Tel: +81-6-6908-0447
Fax: +81-6-6908-5817

Nippon Telegraph and Telephone Corporation:
Teruo Hagino,
Masataka Sakamoto
Public Relations and Information Strategy Group
Planning Department
NTT Cyber Communications Laboratory Group
Tel: +81-468-59-2032
Fax: +81-468-55-1104

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