In 2001 Thomson announced the arrival of mp3PRO, the next generation of mp3. mp3PRO offers two key advantages: enhanced sound quality and improved compression. It provides 128 kbps (kilo bits per second) performance at a 64 kbps encoding rate, thereby bringing genuine CD quality and enabling Internet broadcasters to lower their bandwidth costs.

The new technology has been brought in by Swedish partner Coding Technologies, who initially developed it when researching a hearing device for the deaf. It involves taking the high-quality parts from the lower frequency range of a music file and replicating them up to higher frequencies. Coding Technologies has combined its work with Thomson and Fraunhofer's pioneering work in audio coding, and the result is mp3PRO, which makes it possible to download and store 24 albums on a single CD-ROM.

Using advanced psychoacoustics techniques and music structure analysis, mp3PRO creates files that are more compact than original mp3 files, with equal or better sound quality and complete backwards and forwards compatibility. Existing mp3 files will play completely normal on a new mp3PRO player. New mp3PRO files will play on existing mp3 players, but without the dramatic mp3PRO improvements. Of course, new mp3PRO files played on a new mp3PRO decoder will provide the optimal listening experience!

When making an mp3PRO file, the new mp3PRO encoder splits audio recordings into two parts. One part analyzes the low frequency band information and encodes it into a normal mp3 stream. This allows the encoder to concentrate on less information and allows it to do a better job of encoding. This also maintains complete compatibility to existing mp3 players. The second part analyzes the high frequency band information and encodes it into a part of the mp3 stream that is normally ignored by existing mp3 decoders. New or upgraded mp3PRO decoders will tap into this part of the stream and put the two bands back together, resulting in the full audio bandwidth.

Offering 128 kbps performance at a 64 kbps encoding rate, mp3PRO doubles the digital music capacity of flash memory and compact discs. For example, traditional audio CDs hold about 15 songs, whereas an mp3 CD can hold 150 or more songs encoded at 128 kbps. In the near future, when mp3 CD players incorporate the mp3PRO decoder, consumers will be able to store over 300 songs on an mp3PRO-encoded compact disc.

A recently completed "Subjective Listening Tests on Low Bitrate Audio Codecs" conducted by the European Broadcasting Union (EBU), the largest professional association of national broadcasters in the world, has given mp3PRO high marks in the areas of audio quality and consistent performance.

Codecs tested included mp3, mp3PRO, MPEG-2 AAC, AAC+SBR, Microsoft Windows Media 8, AMR Wide Band, RealNetworks RealAudio 8, and RealNetworks G2.

mp3PRO came out on top at 64 kbps with a quality rated as "excellent" for most test items. At a bit rate of 48 kbps, the report cited the two open MPEG formats combined with Coding Technologies' SBR (Spectral Band Replication) technology, mp3PRO and AAC+SBR, as the most superior codecs and mp3PRO was judged to offer the most balance and reliability, ahead of the proprietary audio codecs WMA, RealNetworks RealAudio 8 and RealNetworks G2. In addition, the report also compared mp3 - the forerunner to mp3PRO - favorably to rivals WMA and RealNetworks, with mp3 outperforming WMA for almost all items included in the test.

MUSICMATCH, the global leader in personalized music software and services, adapted mp3PRO as the codec standard of choice for RadioMX, probably the world's most actively used internet radio service. MUSICMATCH Jukebox is the first digital music player to deliver the new mp3PRO audio format, providing music fans the highest quality recording and playback in any digital music player.

In addition, Thomson and Gracenote joined forces to launch a one-stop digital music solution that combines mp3PRO and the Gracenote CDDB Music Recognition Service, giving software and hardware developers simple, streamlined access to the newest generations of the world's most popular digital audio codec and music recognition service. The solution gives the more than 2,000 commercial CDDB media-player developers streamlined access to mp3PRO encoding and decoding. Gracenote is offering an integrated CDDB/mp3PRO encoding license and SDK, and will facilitate incremental upgrades for licensed applications. Additionally, Gracenote and Thomson are offering unprecedented pricing to all developers. Non-commercial software developers can license a CDDB/mp3PRO decoding/mp3-encoding package on a royalty-free basis, and commercial applications will have access to royalty-free mp3PRO decoding.

mp3PRO basics

Why mp3PRO Technology?
Listening to music compressed with mp3 at 128 kbps sounds great. But if you go to lower bit rates the great sound starts lacking the high frequency components. At bit rates of 64 kbps and below the music may begin to sound dull. The reason is that mp3 at these bit rates runs out of bits to compress the music in full audio bandwidth and with significant detail. In this situation the developers of mp3 had to decide whether their codec should produce mp3 music with distortion (so called "coding artefacts") or with limited bandwidth. They opted for limited bandwidth. And as a result, you experience lower bit rate mp3 as band-limited music with just a few distortions.

Whatis mp3PRO Technology?
To improve the sound quality of mp3 at lower bit rates, Coding Technologies has developed an enhancement technology that gives back the sound the high frequency components. The technology is called "Spectral Band Replication" (SBR). SBR is a very efficient method to generate the high frequency components of an audio signal.

More Details
Combining mp3 with the SBR enhancement technology generates an audio signal with high bandwidth at low bit rates. mp3PRO, the resulting audio format is composed out of two components, the mp3 part for the low frequencies and the SBR or "PRO" part for the high frequencies. Since the "PRO" part requires only a few kbps, the format could be done in a way that it is still compatible with the original mp3 format. This fact allows existing mp3 players to play mp3PRO files. They simply ignore the PRO part. The only requirement is that they also have to support sampling rates of 16, 22.5 and 24 kHz along with 32, 44.1 and 48 kHz. While all (mp3 standard compliant) software players fulfil this requirement, not all portable and CD/DVD players do. To learn whether your mp3 player is capable to play mp3PRO files, please check with its manual or manufacturer.

mp3PRO Players
New players supporting mp3PRO technology will of course utilize both parts of the mp3PRO format to take full advantage of the "PRO" enhancement. mp3PRO players will still fully support mp3 since this is an important part of the new mp3PRO format. Thus you can continue to use your vast collection of mp3 files when upgrading to mp3PRO technology.

Demo Player
mp3PRO technology produces great sound quality at lower bit rates. The free Thomson Demo mp3PRO Player/Encoder software you can download, lets you experience the sound quality of mp3PRO technology at 64 kbps. The feedback we received from first listeners was that the quality of 64 kbps mp3PRO technology was in the range between 96 and 128 kbps mp3. This means that you can get nearly twice the amount of music on a portable and CD player with mp3PRO technology. For example, traditional audio CDs hold about 15 songs. An mp3 CD can hold 150 or more songs encoded at 128 kbps. In the near future, when mp3 CD players incorporate the mp3PRO decoder, you will be able to store over 300 songs on an mp3PRO encoded Compact Disc.

Supported Bitrates
mp3PRO technology can support more bit rates than just 64 kbps. At lower bit rates mp3PRO technology is ideal for web casting and Internet radio. At higher bit rates, mp3PRO technology is perfect for high quality audio transmission and storage. The following bit rates are supported by mp3PRO:
Mono: 18, 20, 24, 32, 40, 48, 56 kbps
LC-stereo: 18, 20, 24, 32, 40, 48, 56 kbps
Stereo: 32, 40, 48, 56, 64, 80, 96 kbps

For more background information about SBR and mp3PRO technology please visit www.CodingTechnologies.com/products/sbr.htm