mp3PRO

Mp3PRO is an extension of the MP3 audio compression method for the proprietary patented method of spectral band replication (SBR), to compensate for the high quality drop in the lowest bit rate of MP3 region ( below about 96 kbps).

It was developed by the Swedish company based in Nuremberg Coding Technologies and officially presented in June 2001. Licensed is by Coding Technologies, Fraunhofer Institute for Integrated Circuits and Thomson multimedia.

Since about 2003, there will not be further developed. A successor format is MPEG -4 High Efficiency Advanced Audio Coding (HE -AAC, AAC , AACplus ) and sets rather than on mp3 on Advanced Audio Coding (AAC).

Technology

Mp3PRO is a downward compatible format, you can also play back mp3PRO files so with conventional MP3 players. When playing, however, is missing in this case at least one full octave high frequencies, which makes the listening experience, especially through muffled sound noticeable. The additional sound information contained in the mp3PRO files that represent particular the high frequency range, but only evaluated by players that support mp3PRO format.

On an acoustic comparison ( auditory impression ) of mp3PRO and conventional mp3 files, it is found that with 80 kbps encoded mp3PRO files generate as 128 kbps mp3 files encoded conventional auditory impression about the same. mp3PRO files therefore demonstrate a similar sound quality at about 35 percent less space than conventional mp3 files. Depending on the genre ( language, techno, pop, classical, etc.) in this case, the mp3PRO or the mp3 file may have a slightly better sound, the sound experience is always subjective.

Both formats - mp3, mp3PRO and - allow the encoding to variable bit rates, resulting in the same file sizes to a significant improvement in sound quality. Neither conventional 128 kbps mp3 files or mp3PRO files achieve transparency in the rule. In mp3PRO files, this is - due to the principle of SBR - in particular therefore not possible because of the high frequency range using the SBR information is completely synthetically reconstructed from the lower frequency range. This does not necessarily affect the perceived sound quality however.

Use

Mp3PRO is used mainly in applications and provide systems which only limited bandwidth available - for example, Internet radio - or where storage space is to be saved.

Probably it was due to a restrictive licensing policy never to break through mp3PRO, although some devices and the widespread mp3 player Winamp, MusicMatch and XMMS also support the mp3PRO format.

Criticism

• According to the manufacturer, a 64 kbps mp3PRO file sounds about the same as a conventional 128 kbps mp3 file. This manufacturer's statement that a 50% space or volume savings promised, then led in many cases to disappointment at the prospects and ultimately to the general reluctance of the market regarding mp3PRO, because actually provides an encoded at 128 kbps conventional mp3 file almost always the sound quality of an encoded at 64 kbps mp3PRO file. Are actually 80 kbps mp3PRO files 128 kbps mp3 files sounded terms approximately equal - the saving is therefore around 35 %, although significantly lower, while still remarkable.
• At bit rates of 96 kbps mp3PRO lose significantly to efficiency and offer little advantage, since the high-frequency range artificially generated having little or only slight resemblance to the original signal.
• When using in web radio is a real-time exchange of mp3PRO to conventional mp3 and vice versa often problematic. It come with the listener to slow down the sound ( mp3PRO to mp3) with jumps or for doubling the sound ( mp3 on mp3PRO ) with breaks. With the subsequent installation of a mp3PRO plug-ins for the player, however, can be solved under certain circumstances this problem.