Bandwidth of telephony audio data   

Sorry if this is a FAQ - if one wants to digitally sample the audio off a 
phone line and store it digitally in 'raw' form w/out significant loss, how 
much storage is needed for, say, one minute of conversation, before 
sophisticated compression like MP3 is applied?

Basically I just need to know what 8kHz * 1 minute equals in bytes.

An estimate is fine. So is a URL.

Thanks.

RDeW

date: Mon, 12 Dec 2005 03:09:26 -0800   author:   Riley DeWiley

Re: Bandwidth of telephony audio data   

"Riley DeWiley"  schrieb im Newsbeitrag
news:p9udnWQ5r731xwDeRVn-iQ@seanet.com...
> Sorry if this is a FAQ - if one wants to digitally sample the audio off a
> phone line and store it digitally in 'raw' form w/out significant loss, how
> much storage is needed for, say, one minute of conversation, before
> sophisticated compression like MP3 is applied?

Riley,
It is recommended to post TAPI questions only to the managed TAPI newsgroup:
microsoft.public.win32.programmer.tapi
See my TAPI and TSPI FAQ:
Q: What newsgroups are covering TAPI ?
http://www.i-b-a-m.de/Andreas_Marschall's_TAPI_and_TSPI_FAQ.htm#_Q:_What_newsgroups

-- 
Best Regards
Andreas Marschall
Microsoft MVP for TAPI / Windows SDK
TAPI / TSP Developer and Tester
My TAPI and TSPI FAQ:
http://www.I-B-A-M.de/Andreas_Marschall's_TAPI_and_TSPI_FAQ.htm
My Toto Tools (a collection of free, mostly TAPI related tools):
http://www.i-b-a-m.de/Andreas_Marschall's_Toto_Tools.htm
TAPI development around the world (Frappr! map):
http://www.frappr.com/TAPIaroundTheWorld
* Please post all messages and replies to the newsgroup so all may
* benefit from the discussion.  Private mail is usually not replied to.
* This posting is provided "AS IS" with no warranties, and confers no rights.

date: Mon, 12 Dec 2005 16:12:00 +0100   author:   Andreas Marschall [MVP TAPI]

Re: Bandwidth of telephony audio data   

Hi Riley,

To (roughly) estimate storage size of raw audio wav files - you need to know 
the sampling rate and the sampling 'size' or width.  8kHz means 8k times per 
second.  8k*60 = 480k.   If the sampling size is 8-bits then that means 
480kb * 1.05 = 504kb per minute. (I am assuming roughly 5% overhead for file 
descriptors and general "organizational" overhead and absolutely no 
compression).  If the sampling width is 16 bit, that would double the raw 
data size, if 24 bit then triple the data size per minute.

This is far from offering precise measurements; most recording algorithms 
incorporate some compression, but this should give you the tools to 
calculate the raw data size.

Hope this helps!

Sincerely,
G

"Riley DeWiley"  wrote in message 
news:p9udnWQ5r731xwDeRVn-iQ@seanet.com...
> Sorry if this is a FAQ - if one wants to digitally sample the audio off a 
> phone line and store it digitally in 'raw' form w/out significant loss, 
> how much storage is needed for, say, one minute of conversation, before 
> sophisticated compression like MP3 is applied?
>
> Basically I just need to know what 8kHz * 1 minute equals in bytes.
>
> An estimate is fine. So is a URL.
>
> Thanks.
>
> RDeW
>

date: Wed, 28 Dec 2005 06:03:45 -0800   author:   News Guys gll2005