[AVTCORE] Adding information to draft-ietf-avtext-framemarking non-scalable extension

[Roni Even <[e-mail]>]

Hi,
The current support for non-scalable frame marking provide limited information for making good decisions about which packets to drop in congestion case. Currently there is only 1 bit for marking discardable packets.

I propose using three of the remaining  four bits (currently 0000) with the following semantics:

Low motion bit (M) - specifying that this stream or the current packets have low motion (example - a conference room meeting ), removing them will just reduce the frame rate with less artifacts comparing with a live video of a basketball game.
Priority (P) two bits - allowing to prioritize frames in a stream. For example if we have a sequence (IBBBBPBBB...) even though all B frames may be defined as discardable, they may have different relation to the other frames and by using priority we can make better discarding decisions.

The way it may work for example  is that when there is a need to discard packets  the middlebox will choose from the discardable packets the ones with low motion and low priority and continue dropping low motion and higher priority. The dropping policy should be implementation dependent.


Roni Even