addTransceiver does not check for uniqueness of rid

[docfaraday]

When passing more than one sendEncoding to addTransceiver, there is nothing in the spec about verifying that the rid properties are unique. This is necessary, in my opinion.

[jan-ivar]

I've tested this and all browsers allow it. I agree it would be better if it threw.

const transceiver = pc.addTransceiver("video", {sendEncodings: [{rid: "hi"}, {rid: "hi"}]});

For symmetry how is a remote offer with a=simulcast:recv hi;hi treated?

[docfaraday]

RFC 8853 does not seem to prohibit duplicate rids in the simulcast attribute, although generating a simulcast attribute with duplicates would definitely be silly. I guess the appropriate thing to do is to ignore duplicates?