re: Bird calls in MP3 format? + sonograms

Subject: re: Bird calls in MP3 format? + sonograms
From: Peter Woodall <>
Date: Thu, 26 Oct 2000 13:48:34 +1000
At 14:14 26/10/2000 +1100, you wrote:
>Paul Foxworthy wrote:
>> At 11:11 26/10/2000 +1100, John Boyce wrote:
>> >recall.  Using an mp3 player (such as a compaq ipaq handheld pda) you
>> >could already have 10 sec or so for each bird and the sound would be
>> >retreivable in a few seconds.  Only available RAM is holding us back.
>> There are MP3 players with 64 Mbyte of RAM available now, and if that's not
>> enough, others have multi-gigabyte matchbox-sized hard disk drives.
>There are also portable CD players that will also play MP3 files
>stored on CD-R (and possibly CD-RW) disks.
>One thing that should be pointed out is that MP3 is a lossy
>compression format i.e. if you decode an MP3-encoded audio file,
>the resulting audio will *not* the same as the original.
>(The JPEG image format also uses lossy compression.)
>How well MP3 works in practice depends upon the how accurate the
>psychoacoustic model is, which is partially dependent on how much
>accuracy you are prepared to sacrifice for better compression.
>(The psychoacoustic model determines which parts of the original
>audio cannot be "heard", and can be discarded to obtain greater
>compression.)  I suspect that birdcalls may show more artifacts
>as a result of compression than music, because it tends to
>contain more information at higher frequencies(?)  If I find
>some spare time, I may try converting some samples of birdcalls
>from CD to MP3, and see if I can hear any difference.  (I've also
>located some tools to visually show the differences in the signals
>before and after compression, and analyze the distortion etc.)
>   Paul Taylor                           Veni, vidi, tici -

Those of you interested in birds calls might try to get hold of the
July 2000 issue of British Birds which has an interesting article by
Slater and Sellar on understanding sonograms.  They give a couple of 
web sites where software to produce sonograms can be downloaded.


Dr Peter Woodall                          email = 
Division of Vet Pathology & Anatomy             
School of Veterinary Science.             Phone = +61 7 3365 2300
The University of Queensland              Fax   = +61 7 3365 1355
Brisbane, Qld, Australia 4072             WWW  =
"hamba phezulu" (= "go higher" in isiZulu)


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