At 02:20 28/08/2003 +0000, you wrote:
>I guess it was rude not to post a file to play with and test drive.
>
>http://home.comcast.net/~richpeet/0148.fla
Great sound record !
I did some tests with the flac codec but also with the ogg vorbis just to
have a better idea about the pro and the con of such compressors. I have
used 2 long sound records respectively of 372Mb and 178 Mb for this purpose=
and, well, =85. I was agreeably surprised !!!
The flac codec is quite efficient and fast enough as the compression level=
is not pushed over 5 . It is really a lossless format. I checked it by
converting an original .wav file in a .flac file and by converting the
.flac file back to a .wav file. The two .wav files are identical. I'm
convinced now I will use it to store my original files !
It is more difficult to have a judgement about the quality of the ogg
vorbis codec as I don't have good conditions to listen the compressed
files (bloody computer fans !!!). The next step will be to make a
furniture to isolate this noise and vibration generator called PC=85
The first sound record is a seabirds colony without seabirds (they were
coming) ! The second one is the same seabirds colony few hours after :
really noisy (some samples available on
http://homepages.paradise.net.nz/waughfil/index.htm).
File 1 (quite seabirds colony, stereo, 48 kHz, 16bit, 33m03)
Raw file .wav PCM: 372 MB
Lossless compression
Flac, compression level =3D5 : 122.3 MB (
1m) ratio =3D 3.0
Flac, compression level=3D8(max) : 121.8 MB (4m20) ratio =3D=
3.0
Lossy compression but really good quality
Ogg Vorbis, quality=3D10 (max) : 105.4 MB
(3m50) ratio =3D 3.5
Ogg Vorbis, quality=3D6 ("audiophile" qlty) : 41.4 MB
(3m40) ratio =3D 8.9
Lossy compression, "medium" quality
MP3 128kbps FraunHofferIIs : 31.0 MB
(1m12) ratio =3D 12
File 2 (noisy seabirds colony, stereo, 48 kHz, 16bit 15m48)
Raw file .wav PCM: 178 MB
Lossless compression
Flac, compression level =3D5 : 83 MB (
40s) ratio =3D 2.1
Flac, compression level=3D8(max) : 82.8 MB (2m) ratio =3D=
2.1
Lossy compression but really good quality
Ogg Vorbis, quality=3D10 (max) : 51.2MB
(1m50) ratio=3D3.5
Ogg Vorbis, quality=3D6 ("audiophile" qlty) : 20.1 MB
(2m) ratio=3D8.8
Lossy compression, "medium" quality
MP3 128kbps FraunHofferIIs : 14.8 MB
(30s) ratio=3D12
(test performed with an AMD 1.8 GHz - 512MB)
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