Hi everyone,

I've got some files that have mp3 extension.
My player shows that they have bitrate 80kbs and frequency 225000.
EncSpot shows me that they are of type mpeg2 layer III.

I wonder what is this mpeg2 layer III? I thought mp3 is of type mpeg1 layer III.

I find that my files are very small in size and still the quality is acceptable.
Anyone that has experience with such encoding? Does it worth to try it? How to encode and how to achieve good results?

Has to do with the samplerate and possible bitrates.

If the sampling rate is lower than 16 KHz, the files are MPEG 2.5.
AFAIK, MPEG 2.5 is not an official standard but was introduced to support low sampling rates.

The mpeg2 specification not only contains a low sampling rate extension but also a multichannel extension.

Sebi

I noticed that the mp3 sound files that are part of the game "Sid Meier's Alpha Centauri" are MPEG2.

A multichannel extension that has never had an encoder implementation AFAIK

There is an MP2 encoder. Check RRW.

Alright no MP3 implementation. The MP2 encoder sounds interesting though

couldn't this be mp3pro, too? I mean if you play a mp3pro file in a non-mp3pro-compatible standard mp3 player a 44kHz file ends up in a 22kHz standard mp3 file. The Spectral Band Replication (or whatever its called ) will not be seen by a standard mp3 decoder and so there are no higher frequencies available even though they are in the mp3pro file.

mp3pro is not part of the official mp3 standard

though, it makes use of mpeg2 (half the sampling rate) layer 3 for the "compatibility layer"

Sebi