datanet wrote:
Hmm, good reply, hel. Only your forgot 16 bits: That's the
width of the data stream, meaning 16 bits at a time is
transmitted in the data stream. Or, ultra-simply, a combination
of 16 zeroes and ones of data at a time is transmitted around the
system. The wider the virtual or literal buss (bit rate), the
faster things are internally and the less problem with
bottlenecks. 32 bit is twice as fast as 16 bit (well, about,
anyway, neglecting some added control bits) and so on.
Pop
wrote in message
...
| RC [Fri, 24 Sep 2004 05:53:11 -0700]:
| "wylbur37" wrote ...
| Each WAV file is saved with certain parameters.
| The following is a typical example of such parameters ...
|
| PCM, 44.1kHz, 16bit, stereo, 172 kbps
|
| I know what the "44.1kHz" (sampling rate) means,
| and what the "172kbps" (bitrate) means.
|
| "172kbps" sounds like a highly compressed format such as
|
| More likely, the person doesn't understand or appreciate
| using proper units:
|
| 176,400 bytes per second is the CD data rate
|
| 176400/1024 = 172.266 KB/sec (not kbps, wrong on two counts)
|
|
| For the curious, 176400 bytes/sec = 44100 Hz x 2 ch x 2
bytes/sample/ch.
|
| 176400 bytes 44100 samples 2 channels 2 bytes
| ----------- = ------------ x x ---------
| sec sec sample / channel
|
| Channels and samples cancel, leaving bytes and sec. 176400
bytes/sec.
| In kbps, that's 176400*8= 1411200/1000= 1411.2 kbps.
|
| Here, LITTLE k (as in kbps) is 1000. Little b is bits.
| BIG K, as in KB, is 1024. Big B is bytes.
|
| Usually, you only see kb -OR- KB, but not kB, nor Kb. Why?
| Because bits are usually described in 1000s (k) of,
| and bytes in 1024s (K) of. The K symbol was purposely
| made "close to" the standard metric k symbol (kilo = 1000)
| since 1024 is "close to" 1000, but a little more (capital K).
|
| (You'd have known this if you didn't skip that day.)
|
| --
| 40th Floor - Software @ http://40th.com/
| iPlay : the ultimate audio player for iPAQs
| mp3, ogg, mp4, m4a, aac, wav, play & record
| parametric eq, xfeed, reverb - all on a ppc
The number of bits has nothing to do with speed. It is simply the width
of each sample. For the audio CD, there are 44,100 of these 16-bit
samples for every second of sound. For the ultimate DVD audio disc there
are 192,000 24-bit samples for every second of sound. The width of the
sample, be it 16 bits or 24, determines the dynamic range you can
capture in digital audio. The rule of thumb is to multiply the bits by 6
to get the maximum dynamic range capability. For 16 bits, that would be
16*6 or 96 db, and for 24 bits it would be 24*6=144db. In reality, due
to limitations in electronics and such, 24 bit systems haven't even come
close to 144 db capabilty. It's more like 108-110db, and 16 bit systems
are around 80 to 85 db.
CD