[Asterisk-Users] ADPCM 4-bit, 6 kHz

[Steve Underwood]

Why do people get this uncontrollable urge to post, when the don't know 
the correct answer? :-)

Regards,
Steve


Leo Ann Boon wrote:

> I think that's the IMA ADCPM format.
>
> Steve Underwood wrote:
>
>> Yves Chouinard wrote:
>>
>>> I found some posts regarding this issue dating of September 2003, 
>>> but no
>>> real answer.
>>>
>>> The ADPCM format supported by Asterisk (the .vox files) is 4-bit, 8 
>>> kHz. I
>>> need 4-bit, 6 kHz, which is also a widespread Dialogic format, to help
>>> migration.
>>>
>>> Is there an existing format/codec for this? If not, can I make myself a
>>> shared object in /usr/lib/asterisk/modules? Is this easy??? :-(
>>>
>>> Thanks,
>>>
>>> Yves Chouinard
>>> Vox-Tel
>>>  
>>>
>> There is no support for this right now. However, as you say, the 
>> OKI/Dialogic 24kbps format is very widely used in the IVR business. 
>> It might be worth having a 6k -> 8K rate converter so the existing 
>> Dialogic 32kbps code can also work with 24kbps Dialogic files.
>>
>> P.S. Just saying 4-bit, 8 kHz or 4-bit, 6 kHz is meaningless. There 
>> are *many* ADPCM formats which fit those descriptions. The format is 
>> OKI ADPCM. Dialogic originally used OKI's ADPCM chips, although all 
>> recent cards implement the codec in a programmable DSP.
>>
>> Regards,
>> Steve
>