First MPEG-4 codec is H.263 compliant......................
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NEC Reports Advances in MPEG-4
7/30/99 New codec targets low-bitrate advantages of MPEG-4 to further the development of Internet and mobile video devices.
NEC Corp. (San Jose, CA) has developed an MPEG-4 coder/decoder codec that enables the transmission and reception of both high-quality audio and video over the Internet and next-generation mobile telephones.
The codec conforms with two important international video data compressing standards: MPEG-4/Visual and H.263 ver.2, an ITU standard for compressing a videoconferencing transmission. These ensure no distortions are caused when data is encoded, while maintaining high picture quality through improved filter processing. For audio standards, the device conforms to the international G.723.1 standard for narrow- (4KHz) and wide-band (7KHz) compression. G.723.1 is an ITU standard for speech codecs optimized for modems
Another important feature of the codec is its ability to send data in periodic cycles. In the event of data errors, they are replaced by correct data to ensure accurate reproduction. In order to process various audio and video signals, the codec also uses the international H.223 Annex B standard, an ITU standard for audio and video data error-correction in mobile communications. The standard ensures speedy performance even when large volumes of data are being processed through more efficient operation of the internal digital signal processor (DSP) in the unit.
Small bitrate, small screen
The codec will enable standard QCIF (quarter common intermediate format) screen size (176 x 144 dots) reproduction in video phones at a rate of 10-15 frames per second (approximately twice the compression/decompression performance of previous systems) with a power consumption of 94mW (half the power consumption of contemporary devices) in a single-chip DSP. At the limited data transfer rate of mobile telephones and multimedia terminals of between 64-128kbps, high-quality video and audio transmissions will be possible in a miniaturized package.
In addition, the DSP and its two audio and video codecs can be embedded in a microprocessor and mounted on a credit card-sized board for analog-digital, digital-analog interfaces.
Codec targets next generation mobile communications
The growth of the Internet and mobile communications allow for the incorporation all forms of audio, graphic and video data. From 2001, next generation mobile communications services (IMT-2000) will get underway and working mobile multimedia communications are expected to become available.
Current uses for codecs with ISDN television conferencing and videophones are not practical for portable terminals in terms of both power consumption and cost. This opens the way for a growing market for low power consumption, high performance, low cost videophone codecs.
These videophones could offer a wide range of multimedia services based on graphical information such as catalogue sales, information on entertainment news such as with movie trailers, traffic and weather conditions. NEC is now moving to miniaturize the device further and enhance its performance before marketing a product based on this codec.
Toshiba developed an MPEG-4 chip in 1998 and is marketing chip-enabled devices to the corporate intranet video market in Japan.
Edited by Tom Butts
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