Add multiple video encode support

[a-wing]

mediamtx support video codecs and audio codecs

protocol	variants	video codecs	audio codecs
WebRTC clients	Browser-based, WHIP	AV1, VP9, VP8, H264	Opus, G722, G711
WebRTC servers	WHEP	AV1, VP9, VP8, H264	Opus, G722, G711

---

H264

gst-launch-1.0 videotestsrc ! video/x-raw,width=640,height=480,format=I420 ! x264enc tune=zerolatency ! rtph264pay ! whipsink whip-endpoint="http://localhost:3000/whip/endpoint/123"

H265

gst-launch-1.0 videotestsrc ! video/x-raw,width=640,height=480,format=I420 ! x265enc ! rtph265pay ! whipsink whip-endpoint="http://localhost:3000/whip/endpoint/123"

VP8

gst-launch-1.0 videotestsrc ! video/x-raw,width=640,height=480,format=I420 ! vp8enc ! rtpvp8pay ! whipsink whip-endpoint="http://localhost:3000/whip/endpoint/123"

VP9

gst-launch-1.0 videotestsrc ! video/x-raw,width=640,height=480,format=I420 ! vp9enc ! rtpvp9pay ! whipsink whip-endpoint="http://localhost:3000/whip/endpoint/123"

AV1

gst-launch-1.0 videotestsrc ! video/x-raw,width=640,height=480,format=I420 ! av1enc ! rtpav1pay ! whipsink whip-endpoint="http://localhost:3000/whip/endpoint/123"

[a-wing]

I test multiple video encode

• [x] H264
• [x] ~H265~ https://github.com/webrtc-rs/webrtc/issues/141
• [x] VP8
• [x] VP9
• [ ] AV1 Have some problem in gstreamer, Maybe bug

[a-wing]

webrtc-rs av1 support 56b7f9bf6eacee4845b7c15ffb2c9ba378ae1234