mediaengine.go

package engine

import (
	"github.com/pion/sdp/v3"
	"github.com/pion/webrtc/v3"
)

const (
	MimeTypeH264 = "video/H264"
	MimeTypeOpus = "audio/opus"
	MimeTypeVP8  = "video/VP8"
	MimeTypeVP9  = "video/VP9"
)

var (
	videoRTCPFeedback = []webrtc.RTCPFeedback{
		{Type: webrtc.TypeRTCPFBGoogREMB, Parameter: ""},
		{Type: webrtc.TypeRTCPFBCCM, Parameter: "fir"},
		{Type: webrtc.TypeRTCPFBNACK, Parameter: ""},
		{Type: webrtc.TypeRTCPFBNACK, Parameter: "pli"},
	}
	videoRTPCodecParameters = []webrtc.RTPCodecParameters{
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeVP8, ClockRate: 90000, RTCPFeedback: videoRTCPFeedback},
			PayloadType:        96,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeVP9, ClockRate: 90000, SDPFmtpLine: "profile-id=0", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        98,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeVP9, ClockRate: 90000, SDPFmtpLine: "profile-id=1", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        100,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeH264, ClockRate: 90000, SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        102,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeH264, ClockRate: 90000, SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42001f", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        127,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeH264, ClockRate: 90000, SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        125,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeH264, ClockRate: 90000, SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        108,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeH264, ClockRate: 90000, SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640032", RTCPFeedback: videoRTCPFeedback},
			PayloadType:        123,
		},
	}
)

const frameMarking = "urn:ietf:params:rtp-hdrext:framemarking"

func getPublisherMediaEngine(mime string) (*webrtc.MediaEngine, error) {
	me := &webrtc.MediaEngine{}
	if err := me.RegisterCodec(webrtc.RTPCodecParameters{
		RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: MimeTypeOpus, ClockRate: 48000, Channels: 2, SDPFmtpLine: "minptime=10;useinbandfec=1", RTCPFeedback: nil},
		PayloadType:        111,
	}, webrtc.RTPCodecTypeAudio); err != nil {
		return nil, err
	}

	for _, codec := range videoRTPCodecParameters {
		// register all if mime == ""
		if mime == "" {
			if err := me.RegisterCodec(codec, webrtc.RTPCodecTypeVideo); err != nil {
				return nil, err
			}
			continue
		}
		// register the chosen mime
		if codec.RTPCodecCapability.MimeType == mime {
			if err := me.RegisterCodec(codec, webrtc.RTPCodecTypeVideo); err != nil {
				return nil, err
			}
		}
	}

	for _, extension := range []string{
		sdp.SDESMidURI,
		sdp.SDESRTPStreamIDURI,
		sdp.TransportCCURI,
		frameMarking,
	} {
		if err := me.RegisterHeaderExtension(webrtc.RTPHeaderExtensionCapability{URI: extension}, webrtc.RTPCodecTypeVideo); err != nil {
			return nil, err
		}
	}
	for _, extension := range []string{
		sdp.SDESMidURI,
		sdp.SDESRTPStreamIDURI,
		sdp.AudioLevelURI,
	} {
		if err := me.RegisterHeaderExtension(webrtc.RTPHeaderExtensionCapability{URI: extension}, webrtc.RTPCodecTypeAudio); err != nil {
			return nil, err
		}
	}

	return me, nil
}

func getSubscriberMediaEngine() (*webrtc.MediaEngine, error) {
	me := &webrtc.MediaEngine{}
	_ = me.RegisterDefaultCodecs()
	return me, nil
}