[asterisk-dev] AST_FRAME_DIGITAL

Matthew Fredrickson creslin at digium.com
Thu Sep 13 17:42:46 CDT 2007


Klaus Darilion wrote:
> Kevin P. Fleming wrote:
>> Matthew Fredrickson wrote:
>>
>>> I can see their point though.  Why do it when you don't have to.  I 
>>> think my propsed AST_FORMAT_DIGITAL with different subclasses that can 
>>> be transcoded using an extension to the translation core would solve all 
>>> of these issues.
>> While I think this is a good plan as well, I don't think the T.38
>> example is actually accurate, because I don't think you can transcode
>> T.38 to analog modem signals on a frame-by-frame basis.
> 
> Isn't it possible to have asynchronous translation? I think this is 
> already needed if you do translation between codecs with different frame 
> duration (e.g. 20ms ulaw and 30ms ilbc)?

My T.38 knowledge isn't that great, but if it's a frame-for-frame issue 
that Kevin thought of, it's certainly possible to buffer multiple frames 
(or enough frames) until we have enough to do a chunk of audio.  But 
it's quite possible that Kevin is thinking of something that I am not.

-- 
Matthew Fredrickson
Software/Firmware Engineer
Digium, Inc.



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