The new audio coding technology also recently won much-needed software support for encoding, playback, content and digital-rights management from companies including MP3.com, WinAmp, Ahead Software and InterTrust.

MP3Pro is an MP3-compatible follow-on that its backers say improves audio file-size efficiency and fidelity. Thomson MultiMedia (Paris) and Fraunhofer Institute (Erlangen, Germany) — the two companies that hold the key intellectual-property-rights to MP3 — developed the next-generation codec with the help of Coding Technologies (Stockholm, Sweden), a Fraunhofer spin-off.

Implementing Coding Technologies' spectral-band replication (SBR) technology, a music file compressed in MP3Pro at 64 kbits/second performs better than MP3 at 96 kbits/s, thus halving the required memory space, according to Thomson MultiMedia. When compressed at 128 kbits/s, MP3Pro allows true CD-quality storage and replay in the home environment, Thomson said.

Conventional MP3 players can render a useful output from an MP3Pro bit stream, and a new MP3Pro player can play back legacy MP3 streams, according to the new codec's developers. "MP3Pro can give consumers the breadth and depth of MP3, without casting away or leaving behind MP3 files already ripped," said a Thomson Consumer Electronics spokesman.

TI valued those characteristics when it decided to port the MP3Pro algorithm to its DSP families. "MP3 is to the music industry what Coke is to the beverage industry," said Chris Schairbaum, worldwide marketing manager of the Internet audio business at TI.

Iffy ascent

Nonetheless, such other audio codecs as Microsoft Corp.'s Windows Media Audio, RealNetworks' RealAudio and MPEG's Advanced Audio Codec (AAC) are all making deep inroads into the Internet audio market. And each, like MP3Pro, touts higher efficiency and improved audio fidelity. The new codec's immediate ascent is not assured.

"They have a long way to go before they make a dent in the market," said Mike Paxton, senior analyst at Cahners In-Stat Group. Both PC and portable audio player suppliers must sign on to the format, Paxton said. Thus far, Thomson MultiMedia is the only system OEM committed to developing MP3Pro-capable jukeboxes and Internet audio players, with systems scheduled for launch next year.

"Millions and millions of files are already made in MP3. Putting yet another codec on the market could overwhelm consumers," Paxton said.

But Thomson is confident the landscape is about to change. Various software components indispensable to supporting the MP3Pro compression format are becoming available through Thomson's strategic partners.

For instance, consumers today can listen to MP3Pro songs at MP3.com with a WinAmp plug-in. For those who want to rip their own MP3Pro files, German company Ahead Software has released a version of its Nero software with a fully functional MP3Pro encoder. And InterTrust Technologies Corp. has integrated the MP3Pro codec with its digital-rights management platform.

Coverage on the digital-rights front was what "content providers very much wanted to hear" before taking MP3Pro seriously, Paxton said.

Hardware support is also coming. TI will port the MP3Pro algorithm to its C54X DSP family by year's end, with a C55X port expected to be completed in the first quarter, said Randy Cole, chief technology officer for TI's Internet audio business.

Core implementation

Coding Technologies, meanwhile, has chosen STMicroelectronics' MMDSP+ digital signal processor core to implement the MP3Pro format. "We already have a development kit based on our 24-bit DSP core — optimized for high-quality audio-processing applications — running the MP3Pro algorithm in RAM," said Riccardo Ferrari, director of STMicroelectronics' Audio Business Unit.

ST is working with equipment manufacturers to evaluate options for commercial hardware decoder chips based on the same DSP and software. The decoders are expected to include the MMDSP+ core, code memory for the MP3Pro software, digital-to-analog converters and other functions.

The company does not yet own an MP3Pro license but has applied for one with Thomson Multimedia and expects to have it within six weeks, Ferrari said. "We decided to investigate the costs of implementation — both design and manufacturing — before paying the fees," he said.

MP3 ASIC vendor Micronas (Freiburg, Germany), meanwhile, "sees MP3Pro as a mainstream audio codec and has it on the road map," said Peter Moeller, marketing manager for personal digital entertainment at the company. "We are analyzing possible implementations, but the specific time frame and technology are dependent on developments in the current market situation."

SBR enhancement

Coding Technologies' SBR is described as an audio-coding enhancement tool for providing efficient coding of high frequencies in audio compression algorithms. The approach is largely a post-process, but some preprocessing is performed in the encoder to guide decoding.

When SBR is used, the underlying coder, such as MP3 or AAC, is responsible only for transmitting the lower part of the spectrum; the higher frequencies are generated by the SBR decoder. Instead of transmitting the spectrum, SBR reconstructs the higher frequencies in the decoder based on an analysis of the lower frequencies transmitted in the underlying coder. To ensure an accurate reconstruction, some guidance information is transmitted in the encoded bit stream at a very low data rate.

Thomson's spokesman said some existing MP3 players using TI's DSP "could be upgraded" to an MP3Pro player via software upgrades. TI's Schairbaum said OEMs must make the business decision whether to turn their older-generation products into new MP3Pro players.

TI's Cole said the computational power needed to run the MP3Pro algorithm on its DSP family hasn't been determined. "We are still working on it. But roughly, it will take half or less of the computational power" made available by a C54X operating at a 160-MHz clock frequency, he said.

STMicroelectronics' Ferrari claimed that "the clock frequency of our MMDSP+ when decoding MP3Pro is less than 30 MHz."

TI expects MP3Pro-enabled consumer audio systems to arrive in the first half of next year.