mp3PRO

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mp3PRO is an extension of the MP3 audio compression process to include the proprietary, patented spectral band replication (SBR) process to compensate for the sharp drop in quality of MP3 in the lowest bit rate range (below about 96 kbps).

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

It has not been further developed since around 2003. A format successor is MPEG-4 High Efficiency Advanced Audio Coding (HE-AAC, AAC +, AACplus) and uses Advanced Audio Coding (AAC) instead of MP3 .

technology

mp3PRO is a downward compatible format, so you can also play mp3PRO files with conventional MP3 players . In this case, however, at least a whole octave of high frequencies is missing during playback, which is particularly noticeable in the listening impression as a duller sound. The additional sound information contained in the mp3PRO files, which particularly represent the high frequency range, is only evaluated by players that support the mp3PRO format.

quality

When comparing acoustically (auditory impression) of mp3PRO and conventional MP3 files, one finds that mp3PRO files encoded at 80 kbps produce roughly the same auditory impression as conventional MP3 files encoded at 128 kbps. With a similar sound quality, mp3PRO files therefore take up around 35 percent less storage space than conventional MP3 files. Depending on the genre (language, techno, pop, classical, etc.) the mp3PRO or MP3 file can have a slightly better sound, whereby the sound impression is always subjective.

Both formats - mp3PRO and MP3 - allow coding in variable bit rates , which leads to a significant improvement in sound quality with the same file size. Neither conventional 128 kbps MP3 files nor mp3PRO files usually achieve transparency . In the case of mp3PRO files this is not possible - due to the principle of the SBR - in particular because the high frequency range is reconstructed completely synthetically from the lower frequency range with the help of the SBR information. However, this does not necessarily have to affect the subjectively perceived sound quality.

commitment

Mp3PRO is mainly used in applications and systems that only provide low bandwidths - for example Internet radio - or where storage space is to be saved.

Probably due to an overly restrictive licensing policy, mp3PRO never made a breakthrough, although some devices and the popular MP3 players 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, which promised a 50% space / volume saving, often led to disappointment among those interested and ultimately to the general reluctance of the market with regard to mp3PRO, because in fact a conventional MP3 file encoded at 128 kbps almost always surpasses the sound quality of one with 64 kbps encoded mp3PRO file. In fact, 80 kbps mp3PRO files are roughly equivalent to 128 kbps MP3 files in terms of sound - the saving is therefore much lower at around 35%, but it is still remarkable.
  • At bit rates of over 96 kbps, mp3PRO noticeably loses its efficiency and offers few advantages, since the artificially generated high frequency range has little or no resemblance to the original signal.
  • When used in web radio, real-time switching from mp3PRO to conventional MP3 and vice versa is often problematic. The listener slows down the sound (mp3PRO to MP3) with jumps or doubles the sound (MP3 to mp3PRO) with pauses. However, under certain circumstances this problem can be solved by installing an mp3PRO plug-in for the player.

literature

  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich et al. 2006, ISBN 3-446-40198-9 .
  • Roland Enders: The home recording manual. The way to optimal recordings. 3rd, revised edition, revised by Andreas Schulz. Carstensen, Munich 2003, ISBN 3-910098-25-8 .

Web links

Individual evidence

  1. ↑ heise.de: mp3 successor enters the race (June 14, 2001)