webrtcsink: Does FEC by default which breaks non-VP8/VP9 codecs
Enabling FEC makes use of Google's broken interpretation of ULPFEC, which only works somewhat reliable with VP8/VP9 but makes it impossible to handle packet loss correctly for other codecs.
This default should probably be re-considered. As another side-effect, enabling ULPFEC also enables RED, and gstrtpredenc.c
currently drops all RTP header extensions except for TWCC.