I am encoding via WebRTC (VP8) and transcoding to H264 (for Safari). I also playback the stream via WebRTC. The transcoded stream will play via RTMP but not WebRTC (the original VP8 plays fine though).
Here is the SDP
v=0\r\no=WowzaStreamingEngine-next 1823938521 2 IN IP4 127.0.0.1\r\ns=-\r\nt=0 0\r\na=fingerprint:sha-256 BB:FA:9B:9F:FB:20:94:BB:24:7B:27:CE:5D:11:0A:31:FE:04:D5:3B:80:34:A6:00:D8:E3:BF:E7:CC:34:34:84\r\na=group:BUNDLE video audio\r\na=ice-options:trickle\r\na=msid-semantic:WMS *\r\nm=video 9 RTP/SAVPF 97\r\na=rtpmap:97 H264/90000\r\na=fmtp:97 packetization-mode=1;profile-level-id=42C01E;sprop-parameter-sets=Z0KAHpZUCg/YCoQAAA+kAAOpg4EABd/AAC7/T8Y4O0JE1A==,aM41IA==\r\na=cliprect:0,0,240,320\r\na=framesize:97 320-240\r\na=framerate:29.97\r\na=control:trackID=2\r\nc=IN IP4 0.0.0.0\r\na=sendrecv\r\na=ice-pwd:da1d0a0e89e597cd4e2e74bb30656405\r\na=ice-ufrag:165b8f08\r\na=mid:video\r\na=msid:{c8224994-2c77-4b81-b183-126955fa545f} {9da5a99c-b318-47ca-a84e-4cdfeafb522f}\r\na=rtcp-fb:97 nack\r\na=rtcp-fb:97 nack pli\r\na=rtcp-fb:97 ccm fir\r\na=rtcp-mux\r\na=setup:actpass\r\na=ssrc:2044394665 cname:{dc4b451e-72a2-482a-a56c-e6f33ab72208}\r\nm=audio 9 RTP/SAVPF 96\r\na=rtpmap:96 OPUS/48000/2\r\na=control:trackID=1\r\nc=IN IP4 0.0.0.0\r\na=sendrecv\r\na=ice-pwd:da1d0a0e89e597cd4e2e74bb30656405\r\na=ice-ufrag:165b8f08\r\na=mid:audio\r\na=msid:{c8224994-2c77-4b81-b183-126955fa545f} {56372ca9-b785-4660-b682-528646c617ad}\r\na=rtcp-mux\r\na=setup:actpass\r\na=ssrc:1104569732