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.
is 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.
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.
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.
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.
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
background information about SBR and mp3PRO technology please visit