The mimeType property of the RTCCodecStats dictionary is a string containing the codec's MIME type and subtype.
This is of the form "type/subtype", such as "video/VP8" or "audio/opus", as defined in the IANA registry of valid MIME types.
A string indicating the code MIME type/subtype.
codecs.mimeType option in parameter passed to RTCRtpTransceiver.setCodecPreferences() and RTCRtpSender.setParameters().codecs.mimeType in object returned by RTCRtpSender.getParameters() and RTCRtpReceiver.getParameters().