On Thu, July 5, 2007 7:15 am, k...@hotmail.fr wrote:
> Hello everybody,
>
> Can anyone tell me if it's possible to change the sampling rate for
the
> G723 codec ( from 8KHz to 16KHz ) and how.
> should this change BitsPerSample?
> should this change the bitrate?
Yes, but you will be disappointed with the results.
The first problem is with the high pass filtering of the input. When you
double the sample rate you, in effect, double the cut-off frequency. I do
not remember what the lower frequency is for G723, but doubling it will
mute male speakers with low pitched voices.
The second problem is that you will need to double the number of LPC/LSP
values to faithfully reproduce the speech.
If you explain why you want to double the sampling rate we can give you
some other options. Perhaps you need to use a wide-band codec.
--
Phil Frisbie, Jr.
Hawk Software
http://www.hawksoft.com