[AVTCORE] Update to RFC5285 allowing both one and two bytes header extensions in the same RTP packet

"Roni Even" <ron.even.tlv@gmail.com> Fri, 11 September 2015 08:13 UTC

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From: "Roni Even" <ron.even.tlv@gmail.com>
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Date: Fri, 11 Sep 2015 11:13:02 +0300
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Subject: [AVTCORE] Update to RFC5285 allowing both one and two bytes header extensions in the same RTP packet
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At IETF94 there was a consensus to allow mixing of one byte and two bytes
header extensions in the same RTP packet.  I volunteered to do the update to


The issue I have s how to pack both one and two bytes in the same RTP


Currently the extension header (as specified by the profile) is 0xBEDE for
one byte only headed extension and 0x100 followed by 4 bits called appbits
for the two bytes header extension 



"The appbits field is 4 bits that are application-dependent and may be

   defined to be any value or meaning, and are outside the scope of this

   specification.  For the purposes of signaling, this field is treated

   as a special extension value assigned to the local identifier 256.

   If no extension has been specified through configuration or signaling

   for this local identifier value 256, the appbits field SHOULD be set

   to all 0s by the sender and MUST be ignored by the receiver."



My proposal is to keep this two options and add a new extension header 0x200
followed by the 4 bits appbits (using the same semantics) and mandate having
first one byte header extensions terminated by a one byte header extension
with ID 15 which in this case will not terminate the header extensions but
signal the start of the two bytes header extension part.


Does this looks reasonable



Roni Even

As individual