Thanks jcolp. I did see that option, but also another forum post where it was suggested this isn’t usually a great idea: Asymmetric_rtp_codec=yes usage
It still could be a good option here, but my only concern is that in practice it might basically be the same as only supporting one codec in the first place, given that Asterisk starts out sending RTP using its own first choice of codec, and then this causes the remote end to switch to that codec anyway.
Do you know if it would be possible to configure Asterisk to start out using the first codec in the 200 response, rather than starting out using its own first choice? Or is it too early to know what’s in the 200 response by the time we start sending RTP?