max-fps/max-br

[aboba]

From Jianlin Qiu:

About max-fps/max-br I don't think it is good idea to signal them in SDP. We're already trying to avoid SDP mungling for bandwidth, we should avoid bring this back.

[fippo]

the VP8 equivalents of those, max-fr and max-fs are also a MUST in RFC 7741 yet the missing support for them one of the longest-standing WebRTC bugs: https://bugs.chromium.org/p/webrtc/issues/detail?id=2488

I think we should keep on encouraging support for this.

[aboba]

max-fps and max-br H.265 parameters have a different meaning than max-fr/max-fs in VP8. In VP8, max-fr and max-fs are the only parameters indicating receive capabilities.

In H.265, we have profile/tier/level negotiation, so other parameters such as max-fps/max-br indicate additional receive constraints (for example, a receiver limited in maximum framerate/bandwidth beyond the indicated profile/tier/level-id). Main profile level-id 3.1 can by default receive 1280×720@33.7 fps. So max-fps is only needed if the receiver cannot handle 33.7 fps for 1280 x 720 resolution and max-br would only be needed if the receiver cannot handle 10 Mbps.

See: https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding_tiers_and_levels

[aboba]

FYI, RFC 7798 Section 7.2.2 says:

" o The capability parameters max-lsr, max-lps, max-cpb, max-dpb, max- br, max-tr, and max-tc MAY be used to declare further capabilities of the offerer or answerer for receiving. These parameters MUST NOT be present when the direction attribute is sendonly."

[aboba]

AVTCORE VI slide is here: https://docs.google.com/presentation/d/1I944U1DmQ4C2f5r5_uEJiOm2N9s4x4B0c1-SPTPPuS0/edit#slide=id.g2473a55bcdf_0_69

Do we want to recommend removal?

[aboba]

Closed via PR #15