[Speex-dev] SPEEX tech specs

B. Mitchell Loebel multinode at earthlink.net
Thu May 3 04:06:58 PDT 2007

Thank you. You're right ... my error ... I meant 
to say 12 bytes (including the 2 bytes for VAD). 
And it is 10ms/frame. No matter ... thank you for 
the SPEEX specs. In terms of quality, what SPEEX 
bit rate compares with G.729 at 8kbps data rate 
please? Is there some reason why you chose the 
20ms frame rate? Do you keep that same frame rate 
for the different bit rates? The faster frame 
rate would seem to better adapt to multiple 
speakers cutting in and out ... yes/no?

Btw, 6 bytes/frame at 50 frames/second seems to 
be 2.4kbps so I'm guessing that the lower rate 
you mentioned is because of some overhead for VAD in your 6 bytes.

At 07:11 PM 5/3/2007 +1000, Jean-Marc Valin wrote:
>B. Mitchell Loebel a écrit :
> > How many bits do you have in a frame please and what is your frame rate?
> > For example, G.729 (ACELP) has 12 bits/frame including VAD and the frame
> > rate is 100/second ... I'm looking for the comparable figures for SPEEX.
>I'm sorry but if G.729 used 12 bits/frame at 100 frames/second, it would
>have a bit-rate of 1.2 kbps. G.729 actually uses 10 *bytes* (i.e. 80
>bits) per frame. Speex has 20 ms frames (50 frames per second) and
>supports bit-rates that range from 2.15 kbps (6 bytes per frame) to 44
>kbps (110 bytes per frame).
>         Jean-Marc

B. Mitchell Loebel, CEO, VP 
Engineering                              408 425-9920
InstaFlash International Corporation
(formerly Minute-Tape International Corporation)
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