FreePBX 2.11 (Asterisk 11)
8 khz .wav file works fine.
When I try to play the 16 khz .wav file, i get error:
format_wav.c: Unexpected frequency mismatch 16000 (expecting 8000)
(I tried to rename the file to .wav16, but it also can not be played)
How to get the FreePBX to play the 16 khz wav files?
What are you trying to do? Everything in Asterisk typically lives at 8k mono.
FreePBX doesn’t support or not support anything.
FreePBX is like a Ferrari
Asterisk is the F136GT Engine that makes it go vroom
Asterisk typically uses ulaw or alaw which is 8k
Most things in the phone world use 8k. Anything higher would have to be trans-coded to 8k so they use 8k native. If there is a noticeable quality problem (on a phone not your PC) then they were likely down-sampled wrong.
The current standard is wideband codecs. (like G.722 16 khz)
Strange, that the FreePBX does not support 16 khz sound files… ((
Strange, I’ve never found 8Khz to sound bad in terms of quality. But it does depend how you record the announcements. I always use a professional recording company.
I can easily hear the difference between 8 khz and 16 khz, and between 16 khz and 22.05 khz.
on a phone?
This is for your PBX not your ipod
we use sip-softphones and headsets.
Your softphones are almost certainly using a codec that has a high frequency rolloff filter of 3.5khz.using a higher bitrate that 8KHz requires transcoding and wasted CPU cycles, if you don’t believe me ask Nyquist.
Bell spent a ton of research on speech intelligibility and found that increasing beyond the 3Khz actually reduces intelligibility.
You may sense more of the persons analect/dialect but you will know here the speech information clearer.
Bottom line is I agree the wideband CODEC’s don’t sound better.