Coding Technologies announced today that STMicroelectronics is developing a DSP-based decoder chip for Coding Technologies' new mp3PRO standard, the next generation of the MP3 audio coding standard. mp3PRO reduces file size and enhances audio quality yet guarantees both backward and forward compatibility. The new decoder chips are destined for portable music players and are expected to reach the market in early 2002.
A leading producer of decoder chips for the existing MP3 standard, STMicroelectronics is working closely with Coding Technologies, the inventor of mp3PRO, to implement the new algorithm for the company's MMDSP+ digital signal processor core. This 24-bit digital signal processor (DSP) is optimized for high quality audio processing applications and is used by ST in many products for music decoding, speech recognition, echo canceling and so on. Thanks to the use of this optimal DSP core, ST's mp3PRO decoder chips will consume less power, extending battery life in portable players.
"The availability of mp3PRO support in hardware platforms is a crucial component of the market introduction strategy for mp3PRO", said Martin Dietz, President and CEO of Coding Technologies. "We highly appreciate the co-operation with STMicroelectronics to support the mp3PRO technology. ST's MMDSP+ is one of the platforms best suited for audio coding algorithms.
mp3PRO is widely expected to be adopted by equipment makers and consumers because it is compatible with the highly popular MP3 standard. Files coded with the new mp3PRO method can be used with any existing MP3 player, both hardware and PC-based software. When played through an mp3PRO-capable player, the consumer will experience the full benefit of mp3PRO, offering high audio quality at a significantly lower file size. Decoders for the new mp3PRO standard will play all existing MP3 files.
"STMicroelectronics is convinced of the high potential of mp3PRO in the marketplace", said Riccardo Ferrari, Director of ST's Audio Business Unit. "We are proud to be one of the first companies to support mp3PRO and welcome the assistance of Coding Technologies in the system integration."
To achieve CD-like audio quality with MP3 a bit rate of 128Kbits/s is needed. With mp3PRO the same quality can be obtained using just 64Kbits/s. This means that on a standard compact disk the number of songs that can be stored increases from about 150 to 300. Since mp3PRO requires less bandwidth than MP3 it will also allow streaming Internet audio to be used reliably over lower speed connections, allowing more users to take advantage of Internet radio services.
A development platform with RAM-resident software has already been developed by STMicroelectronics for evaluation. The company is currently evaluating with equipment makers possible options for commercial hardware decoder chips based on the same DSP and software and will announce sampling and delivery dates later in the year. Details have not yet been released, but these decoder chips are expected to include the MMDSP+ 24-bit audio DSP core, code memory for the mp3PRO software, digital-to-analog converters and other functions. Very few external components will be required.
mp3PRO achieves smaller file size, better audio quality and compatibility thanks to a Coding Technologies innovation called Spectral Band Replication. During the coding of the file the audio spectrum is separated into two bands, one for low frequencies and one for high frequencies. The low frequency band is coded using the standard MP3 method, but since it does not have to take care of the high frequencies the coding is more efficient and the file size will be smaller. The high frequency band is processed separately and added in a way to ensure that it will be ignored by older MP3 decoders.
Standard MP3 decoders decode only the low frequency band, while mp3PRO decoders decode also the high frequency band, reconstructing a wider audio bandwidth.