Subject: [avtext] Frame marking header extension

From: Stephan Wenger <[email-masked]>
Date: Fri, 27 Mar 2015 23:32:52 +0000

Hi,

I was asked to also put the comment below on the list, which I hereby do.

The frame marking draft seems to be a good and useful technology, however it could be made somewhat more future-proof.  In particular, I suggest that the "mandatory one byte header" should be extended to include a few reserved bits for future use.

Another issue that came to my mind is that your hypothetical middle box does not know which codec is in use (and thereby cannot interpret the codec-specific fields correctly) without intercepting and interpreting the signaling.  At least one of the authors of this draft is known to be as a big fan of self-describing RTP (to the extent possible) :-).  Perhaps you want to spend a few bits of the extended mandatory one byte header proposed above to provide in-band info what codec is in use?

Stephan