DaveC wrote:

On Sun, 23 May 2004 11:06:44 -0700, philicorda wrote
(in article pan.2004.05.23.18.06.40.307716@nospnospamspaammnt lworld.com):

Bit rate is independent of sample rate.
So, you can encode a 44.1k mp3 at 128kbps, or 256kbps or whatever.
The sample rate remains the same, but the fidelity is less.

So why not use the term "resample rate" rather than bit rate. The latter
implies streaming data, to me, at least. "Rate" implies a period of time over
which the "128K" -- or whatever -- takes place, when in fact it's just a
combination of the re-sample rate (ie, 22.05K) and the resultant file size.

Not just arguing terminology, here, but hoping that my premise is understood,
helping me better understand. (Understand?) :-)


Actually, the terminology is important. I think your error is
using the term "resample". Those rates may be different due to
the sample size (in bits) that was chosen.

The data isn't resampled to stream, it's compressed into an MP3
format in order to send over the net.

The original recording is sampled at a fixed rate (samples per
second) which produces a fixed number of bits per second (i.e.,
based on the bits per sample). That means to play it back exactly
as it was recorded, you have to play it back at that specific
fixed number of bits per second in order to regenerate the sound
at the original sample rate. However, that is a LOT of data and
bits per second and not really feasible for streaming over the
internet (impossible if you have a dialup connection).

MP3 provides a way to compress the data by digitally rearranging
it and throwing away MANY bits of audio data in a way that the
sound is not impacted too much. The more you throw away, the less
data that you have to stream over a given time and hence the
ability to use a lower speed connection (e.g., like a 56kbps
dialup connection). However, more data thrown away means less
quality of the sound compared to the original. On a higher speed
connection you can use less compression and keep more of the
original data and hence a better quality sound.

- Jeff