Re: [AVT] RFC3558 header-free packet format question

Hi Qiaobing,

As I understand it from when the format was developed: The header-free 
format exist to enable ROHC-LLA to be used and the resulting IP stream 
to be mapped onto a CDMA2000 bearer that only have room for the voice 
frames. As this configuration does not have any space for any extra 
payload headers the header free format was developed.

Cheers

Magnus

Qiaobing Xie wrote:

> Hi, Adam,
> 
> The text in section 4.2 of RFC3558 **seems** to indicate that only ONE 
> speech frame is allowed per RTP packet when header-free format is used. 
> This seems to be overly limiting and may severely hinder the usage of 
> this payload format (e.g., I don't think any over-the-air link can 
> afford to use one frame per RTP packet arrangement, and if over-the-air 
> link can not use header-free format, what would be its purpose?). One 
> would think that as long as the same codec rate (hence the layout and 
> size) is in use, more than one frame should be able to be unambiguously 
> carried in a header-free RTP packet.
> 
> Maybe I missed something.
> 
> regards,
> -Qiaobing
> 
> 
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> https://www1.ietf.org/mailman/listinfo/avt
> 

-- 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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