[Icecast] Questions on setting up icecast
geoff at hitsandpieces.net
Fri Sep 24 22:15:29 PDT 2004
> What's the difference between bitrate and samplerate? Samplerate is like
> 44KHz or 48KHz?
Yes. Sample rate says how many samples of the sound are taken per second.
The bit rate is how many bits are used to store a representation of those
Lets use an example. Suppose we have three files, all at 64kbps. One is
44.1kHz mono, one is 22.05kHz stereo and one is 22.05kHz mono. Now, all
use 64000 bits per second to store the sound. The 22.05kHz mono file
should, at least in theory, be the most faithful reproduction of the
22.05kHz sound, since it's using the same amount of data to compress half
the sound of either of the other two versions. The 22.05kHz stereo file is
using the same amount of data to compress two channels, so the amount of
data per channel that is available is less, resulting in a lower quality
representation of that 22.05kHz sound. The 44.1kHz signal has twice the
resolution of the 22.05kHz signal, but again is only using the same amount
of data. It's like trying to squash a picture that's twice the size into
the same amount of data - it can be done, but depending on how well that
compression works, the result mightn't be very good.
Streaming formats are always a compromise between sampling rate and bit
rate. If you're wanting to set up a stream for a modem listener, you need
to ask yourself - do I want the highest sample rate possible knowing that
it might not represent very well, or do I want a lower rate which will
reproduce better, or maybe do I want a stereo stream versus a mono one.
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