DATA REDUCED AUDIO CODECS
We have reviewed the quality
of some of the newer audio data reduction schemes. So far we are most impressed
with The FLAC (Free Lossless Audio Codec) encoder-decoder. This is open
source code and is superior in quality to all of the data reduction codecs
we have reviewed so far. The files encoded using this scheme are so good
as to result in full cancellation of audio data when FLAC encoded and decoded
Aachen Head recordings, are converted back to PCM format, inverted in phase
and summed with the original audio file. A truly outstanding accomplishment.
For more information go to:http://flac.sourceforge.net/
Also review the FRAUNHOFER MP3
codec (or more correctly MPEG level 1, layer 3) perceptual coder and decoder.
The decoder is available at the Fraunhofer Site in Germany and has good
technical data on the MP3 scheme and a wealth of MP3 information at:http://www.iis.fhg.de/amm/download/index.html#1
We think it will be well worth
your time to download this decoder, particularly if you are used to the
poor quality of MP3 codecs. Aachen Head recordings, which are highly demanding,
seem to hold up reasonably well when coded using the Franhofer codec. Interestingly,
after some analysis we have discovered that the M3u versions, which are
"streamed" MP3 files do not hold up well. MPEG 2, Level 3 was never designed
as a streamed format because of the decoding processor power demanded.
"Aachen Head TM" recordings when played back in this "streamed" mode lose
much of the sense of dimension and space. We have tried the decode on 3
systems with both AMD and Intel (tm) processors running at high speed with
equally poor results.
file is 2.4 meg. Interestingly, when decoded properly, it sounds almost
as good as the 31 meg. file it was generated from. Some artifacts are observable
at low levels, but all in all it is very impressive. Download the FRAUNHOFER
decoder if you do not have it and the demo file. Then, please audition
this recording on a good quality audio system on loudspeakers and for a
real treat, with good quality headphones. You will hear a DC10 Fly over,
a Brass Choir in the round, Percussion in Real Acoustic Space, an intimate
Jazz Club and the last few bars of the Score from Air Force One. Let us
know what you think?
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