Description
a=rtcp-fb:* means that all codecs in this m= section support the RTCP features exposed in this attribute line. Purpose of it is to save space in the SDP by reducing number of a=rtcp-fb lines per m= section. libwebrtc will support this soon so we must be ready in mediasoup-client and libmediasoupclient.
Example:
a=rtcp-fb:* transport-cc means that all codecs in this m= section support transport-cc.
NOTE: This is a SDP thing. We transmit ORTC parameters from client to mediasoup and vice-versa. AFAIU we don't need to support this neither in mediasoup side nor in the ORTC parameters, utils and definitions within mediasoup-client and libmediasoupclient.
So basically, when we parse a SDP and generate RtpParameters or RtpCapabilities must be ready to manage a=rtcp-fb:* lines and apply their supported RTCP features into all codecs within the generated RtpParameters or RtpCapabilities. This is just an estimation, things may need to be different.