asterisk users - Aug 2005 - Asterisk and Wave files problem

Hi,
I'm recording wave files but I cant get Asterisk to play them, only if they 
are in 8000 Hz. What is the maximum sample rate Asterisk can handle? I have 
been using 16-bit 44.1, 22050 and finally 8000 kHz.
Many thanks,
Christian

Christian wrote:
> Hi,
> I'm recording wave files but I cant get Asterisk to play them, only if 
> they are in 8000 Hz. What is the maximum sample rate Asterisk can 
> handle? I have been using 16-bit 44.1, 22050 and finally 8000 kHz.
To my knowledge, the only correct format for wav files to use in 
asterisk is 16-bit 8 kHz. 8-bit is also possible, but will result in 
considerably worse quality.

http://www.voip-info.org/tiki-index.php?page=Asterisk%20sound%20files

Any sample rate higher than 8 kHz would be useless because most POTS 
providers filter their calls at around 4 kHz anyway. The sample rate you 
need to encode a signal is (at least) twice the maximum singal 
frequence. This leads to a sample frequency of 8 kHz . I'm not sure if 
this is the reason why asterisk limits the use of wav files to 8 kHz. 
Since a phone line uses a 12 or 13-bit compressed signal at a sample 
rate of 8 kHz, using a higher frequency for wav files would imply the 
need to downsample on the fly. This could result in quite some 
performance loss.

"Christian" <christian08@gmail.com> writes:
> only if they are in 8000 Hz
Asterisk only handles 8kHz, or so I understand. There is some work to
get it to do more. Would be very nice for us that only use asterisk
for voip between softphones and have no interest in hardware or
telephone networks what so ever;). Doing speex at ultra wideband
32kHz would be awesome.

-- 
Esben Stien is b0ef@e     s      a             
         http://www. s     t    n m
          irc://irc.  b  -  i  .   e/%23contact
          [sip|iax]:   e     e 
           jid:b0ef@    n     n