[asterisk-dev] AST_FRAME_DIGITAL

[Klaus Darilion]

Russell Bryant schrieb:
> Christian wrote:
>> I vote for AST_FRAME_DIGITAL too! I think i suggested that about over 
>> one year already..  It would be very useful to transport Digital Data 
>> like HDLC Frames which might occur in the media channel of chan_zap and 
>> chan_misdn. At the moment such data would be sent with AST_FRAME_VOICE 
>> which is not appropriate.
> 
> I will not argue that such a thing would not be useful.  However, I want to be
> _very_ strict about what it could be used for.  In the context of this thread,
> where the stream is actually voice and video, it is absolutely not appropriate.

What about G3 fax. It is rather the same as 3G video:
  fax delivers images over a telephone line
  3G video deliver audio and video over a telephone line

In case of G3 fax, the image data is modulated
In case of 3G video, the audio/video is multiplexed with H223.

Currently fax is handled inside an application. Taking your argument, 
the fax decoder should be in the channel driver and deliver 
AST_FRAME_IMAGE (maybe one per page) to Asterisk's core. But I think the 
current implementation which is a single application is much better then 
adding modem functionality to each channel driver.

IMO it is much more flexible only add support for generic data 
(AST_FRAME_DIGITAL) to channel drivers. Then, new services and features 
can be added as application without touching the code of channel drivers.

regards
klaus