Bit-resolution decrease for internet

"Rich Andrews" <n0way@yahoo.com> wrote in message
news:Xns945D2E01E864Bmc2500183316chgoill@216.168.3.44...
> glucegen@excite.com (Radium) wrote in news:464c821f.0312210007.28591132
> @posting.google.com:
>
> > Jerry Avins <jya@ieee.org> wrote in message news:<3fdfccea$0$4752
> $61fed72c@news.rcn.com>...
> >> I give up.
> >
> > Me too. I now realize that digital information cannot be less that one
> > bit. I must admit this is one of my stupid threads which I started
> > w/out sufficient research. Sorry.
>
> Tis OK.  I have done worse.  The willingness to learn should never be
> stifled.
>
> r
>
>
> --
> Nothing beats the bandwidth of a station wagon filled with DLT tapes.

I think a C5A full of DVD-R's would...  :-)

   Best wishes,
   --Phil Martel

"Radium" <glucegen@excite.com> wrote in message
news:yvivfonmgeb.fsf@jpff.cs.bath.ac.uk...
> Wrong. 1 Hz sampling rate would equate to .5 Hz. Sampling rate must be
> at least 2x the maximum frequency.
>
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
>
> Bit-rate = sample-rate X bit-resolution X numbers of channels
>
> Multiply the 44100 X 2 X 1/88200 and you get 1!
>
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second
>
> 1 minute of this file would comsume 60 bits of disk space.

Consider this logically for a second...
The lowest possible bit depth for a single sample is 1 bit, hence you must
have at least 1bit per sample.
If you want 400kHz sample rate then you must have a minimum of 400kbps data
rate.
1 minute of this data would consume 2400kb.

Radium wrote:
> Wrong. 1 Hz sampling rate would equate to .5 Hz. Sampling rate must be
> at least 2x the maximum frequency.

OK, so whats the maximum frequency you would like to capture?  (More to the
point, what sampling rate do you propose)

> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second.

Only if you could represent the samples in fractions of a bit.

> If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.

And how do you propose to represent such fractional bits?

> Bit-rate = sample-rate X bit-resolution X numbers of channels

Fine, but you can't have less than one bit per sample.

> Multiply the 44100 X 2 X 1/88200 and you get 1!

Well done.

> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second

Fine.

> 1 minute of this file would comsume 60 bits of disk space.

Yes, but even if it was possible, it would not really be classed as sound,
would it?

The reason the "bit resolution" is 16bits in CD Audio is because then you
can represent the varying wave with some degree of precision.  If you took
that down to one bit, you would be turning sinusoids into square waves,
which would introduce just a tiny bit of odd-harmonic distortion.  That
would result in bps = sampling rate * channels.

Ben
-- 
A7N8X FAQ: www.ben.pope.name/a7n8x_faq.html
Questions by email will likely be ignored, please use the newsgroups.
I'm not just a number. To many, I'm known as a String...

"Radium" <glucegen@excite.com> wrote in message
news:yvivfonmgeb.fsf@jpff.cs.bath.ac.uk...
>>
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second
>
> 1 minute of this file would comsume 60 bits of disk space.

Hello Radium,

At this rate, a 700MB CD will hold 177 years' worth of music!!
Why don't you compress some music to be just 1 bit per second and see if
anyone would be willing to listen to it more than once. I think you need to
check how you are handling your units. The Hz times 1/Hz units cancel out.

Clay

glucegen@excite.com (Radium) wrote in message news:<yvivfonmgeb.fsf@jpff.cs.bath.ac.uk>...
> Wrong. 1 Hz sampling rate would equate to .5 Hz. Sampling rate must be
> at least 2x the maximum frequency.
> 
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
> 
> Bit-rate = sample-rate X bit-resolution X numbers of channels
> 
> Multiply the 44100 X 2 X 1/88200 and you get 1!
> 
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second  
> 
> 1 minute of this file would comsume 60 bits of disk space.

Simple question: What is or how do you make a fractional bit? Digital
systems are quantized. One bit implies quantising to two levels On or
Off. What are the quantization levels of a fractional bit and how
would you represent it?

Regards,


Paavo Jumppanen
Author of AtSpec : A 2 channel PC based FFT spectrum analyzer
http://www.taquis.com

"Radium" <glucegen@excite.com> wrote in message
news:yvi65gb7hl0.fsf@jpff.cs.bath.ac.uk...
> 1 Hz sampling rate would equate to .5 Hz. 1-bit/sec, however would
> not. Bit/time is the bit-rate. Sample rate is different from bit-rate.
> It is also important to know the difference between *bit-resolution*
> and *bit-rate*.
>
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
>
> Bit-rate = sample-rate X bit-resolution X numbers of channels
>
> Multiply the 44100 X 2 X 1/88200 and you get 1!
>
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second
>
> 1 minute of this file would comsume only 60 bits of disk space. It
> would definitely work for the internet. Unlike conventional MP3s and
> WMAs, the high-frequency content of the PCM music will be restored due
> to the high sample rate.

I honestly think you're going about this all wrong:
Ask any audiofile and they'll say that the sound is much better with a
higher sample rate and bit resolution....
Clearly the answer is to reduce the number of channels of audio.

If you have the number of channels as
num channels = bit-rate / (bit-resolution X sample-rate)
then you can still have a 1bit per second for the bit rate, but you can now
have a huge sample rate and an awesome bit resolution.  I mean you could
easily get 192bits per sample, and some 6MSPS with this system.  You would
just have to only use 868.056x10^(-12) channels.

I'm pretty sure that everyone else in this newsgroup will agree with me that
this is more the approach that you should utilise radium...

lol

Radium wrote:
> 1 Hz sampling rate would equate to .5 Hz. 1-bit/sec, however would
> not. Bit/time is the bit-rate. Sample rate is different from bit-rate.
> It is also important to know the difference between *bit-resolution*
> and *bit-rate*.
> 
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
> 
> Bit-rate = sample-rate X bit-resolution X numbers of channels
> 
> Multiply the 44100 X 2 X 1/88200 and you get 1!
> 
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second  
> 
> 1 minute of this file would comsume only 60 bits of disk space. It
> would definitely work for the internet. Unlike conventional MP3s and
> WMAs, the high-frequency content of the PCM music will be restored due
> to the high sample rate.

Hey Radium,

If you're so sure about your analyses, then knock yourself out. Go ahead and
construct a CODEC that will blow the socks off WMA, MP3, etc. and show us
all up.
-- 
%  Randy Yates                  % "...the answer lies within your soul
%% Fuquay-Varina, NC            %       'cause no one knows which side
%%% 919-577-9882                %                   the coin will fall."
%%%% <yates@ieee.org>           %  'Big Wheels', *Out of the Blue*, ELO
http://home.earthlink.net/~yatescr

glucegen@excite.com (Radium) wrote in 
news:yvi65gb7hl0.fsf@jpff.cs.bath.ac.uk:

> 1 Hz sampling rate would equate to .5 Hz. 1-bit/sec, however would
> not. Bit/time is the bit-rate. Sample rate is different from bit-rate.
> It is also important to know the difference between *bit-resolution*
> and *bit-rate*.
> 
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
> 
> Bit-rate = sample-rate X bit-resolution X numbers of channels
> 
> Multiply the 44100 X 2 X 1/88200 and you get 1!
> 
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second  
> 
> 1 minute of this file would comsume only 60 bits of disk space. It
> would definitely work for the internet. Unlike conventional MP3s and
> WMAs, the high-frequency content of the PCM music will be restored due
> to the high sample rate.

Methinks something is wrong with the math and/or definitions.

The way I understand it, if one samples at 44.1kc that means that 44 
thousand times per second you have a 16 bit word.  Thus, in one second, 
you have 44,100 16 bit words of data.  Put another way, in one second you 
have 44,100*16*2(for stereo) or 1,411,200 bits of data.

1,411,200 / 8 = 176400 8 bit bytes per second.

Now if you are wanting to change the sampling resolution or depth from 16 
bits to something like 8 or even 4, the result would not be very good.  I 
believe that there are examples of 4 amd 8 bit on the net.

r




> 
> 
> Rich Andrews <n0way@yahoo.com> wrote in message news:
<yvi1xrcobq0.fsf@jpff.cs.bath.ac.uk>...
>> glucegen@excite.com (Radium) wrote in 
>> news:yvik75eq9k7.fsf@jpff.cs.bath.ac.uk:
>> 
>> > I would like to use an audio codec based on WAVE PCM. It should be a
>> > little different though. The bit-resolution should be set to equal
>> > 1/(sampling rate X # of channels). The bit-rate should be set to 
equal
>> > 1 bit per second. I would like to use this codec to transport audio
>> > files though the internet via email.
>> > 
>> > I am looking for frequency response. In digital audio the sampling
>> > rate must be at least twice the highest frequency in the signal. It
>> > would like a highest frequency of at least 200 KHz. This would 
require
>> > a sample rate of at least 400 KHz.
>> > 
>> > In this codec the bit-resolution is decreased to maintain a low bit
>> > rate of 1 bit/sec. The bit-resolution is divided by the sampling rate
>> > and the # of channels to acheive this.
>> > 
>> > 
>> > 
>> 
>> 1 bit per second?  Wouldn't that equate to .5 hz or did I miss 
something?
>> 
>> r
> 
> 
> 



-- 
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

glucegen@excite.com (Radium) wrote in message news:<yvi65gb7hl0.fsf@jpff.cs.bath.ac.uk>...
> 1 Hz sampling rate would equate to .5 Hz. 1-bit/sec, however would
> not. Bit/time is the bit-rate. Sample rate is different from bit-rate.
> It is also important to know the difference between *bit-resolution*
> and *bit-rate*.
> 
> If in a wave file, the bit-resolution is made to equal 1 /(sampling
> rate X number of channels), then the bit-rate will definitely be
> 1-bit/second. If the sample rate is 44,100 Hz in a stereo (2-channel)
> wave file of this type, the bit-resolution would be 1/(44100 x 2)-bit
> or 1/88200-bit.
> 
> Bit-rate = sample-rate X bit-resolution X numbers of channels
> 
> Multiply the 44100 X 2 X 1/88200 and you get 1!
> 
> 44100 Hz X 1/88200-bit X 2 channels = 1 bit per second  
> 
> 1 minute of this file would comsume only 60 bits of disk space. It
> would definitely work for the internet. Unlike conventional MP3s and
> WMAs, the high-frequency content of the PCM music will be restored due
> to the high sample rate.

Kind people, stand up and give Radium a hearty Huzzah!, for he 
has volunteered for the role of Village Idiot, a job for which 
has has proven himself truly qualified.

Ben Pope wrote:
> Radium wrote:
> > 1 minute of this file would comsume 60 bits of disk space.
> 
> Yes, but even if it was possible, it would not really be classed as sound,
> would it?

You'd be surprised. If I present you with the string "SILENTNIGHT", which can
be represented in just under 60 bits using radix-50 encoding, you probably get
about 1 minute of music playing in your head (depending on how many verses you
know :-). If your computer has a library of recordings, you could actually
play the music.

The point is, when you go to very high orders of compression, you have to
limit the set of possible things that can be represented. Most DSP engineers
discuss systems that are capable of representing arbitrary waveforms of
unspecified duration, but that does not by any means represent the limit
of what's possible for speciallized applications.

As a more practical example, MPEG can readily achieve usable results at well
under 1 bit per sample, for both audio and video.

-- Dave Tweed