From my understanding, variable Bit Rate options -- one pass or two
pass VBR are common settings for various MPEG compression schemes,
usally pertaining to compression of Quicktime video. I have never heard
of using it for Audio formats like MP3, but I have also never messed
with the MP3 compression settings and any of my converters.
Aside for converting stereo audio and 5.1 surround mixes to Dolby
Digital (AC-3) for DVD authoring purposes, I don't have much personal
use for other compressed audio codecs like MP3 grade MPEG . From my
understanding, the new iPods prefer the iPod Codec settings that come
with the new version of Quicktime Pro, which appears to be AAC
compressed audio (48kHz) linked to video transcoded to the H.264 video
Codec, 320X 216 aspect ratio, Millions of colors @696.09 kbits/sec on
this particular file I am looking at for reference, which I exported
from QT-Pro.
In general, while I have experimented with various bitrates for
compressed audio, I am guessing VBR may not be appropriate or applicable
for most nature recordists' needs -- at least from my understanding of
its intended context and purpose.
All the best,
Jeff Daub
oryoki2000 wrote:
>"1GDW" wrote:
>
>
>>Is [variable bit rate (VBR)] something we should be exploring?
>>
>>
>
>VBR is most commonly used in a form of MP3 compression.
>MP3 throws away a large portion of the original file
>to make the MP3 version much smaller. Sometimes an
>MP3 file is only 15% the size of the original. MP3 is
>fine for casual use, as in a portable music player,
>or to speed up downloads from an online sound library.
>
>MP3 is not recommended if critical listening, scientific
>use, or commercial production is planned.
>
>Most, but not all, modern MP3 players know how to decode
>an MP3 file that uses VBR. I've read that Apple's iTunes
>doesn't get along with VBR.
>
>If your goal is reducing file storage requirements, take
>a look at FLAC, the Free Lossless Audio Codec. A FLAC
>version is usually only 50% of the size of the
>original recording. Unlike MP3, a FLAC file can easily
>be converted back into the original WAV format without
>loss of data.
>
>Unfortunately, most music players don't understand FLAC
>format. So the FLAC file has to be decompressed into WAV
>format before most players can use it.
>
>--oryoki
>
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