WebRTC Softphone Codec Negotiation with BYOC Trunks

Configuring WebRTC softphones for agents handling traffic routed through our Singapore BYOC trunks. The carrier mandates OPUS codec for inbound leg, but the softphone defaults to G.711. Result is one-way audio or immediate hangup on SIP 488.

Is it possible to enforce specific codec preferences at the WebRTC connection level before the media reaches the BYOC trunk interface?