Fix support webrtc creality format #1600

Author: AlexxIT

internal/webrtc/client_creality.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/webrtc"
+	"github.com/pion/sdp/v3"
 )
 
 // https://github.com/AlexxIT/go2rtc/issues/1600
@@ -27,7 +28,6 @@ func crealityClient(url string) (core.Producer, error) {
 
 	medias := []*core.Media{
 		{Kind: core.KindVideo, Direction: core.DirectionRecvonly},
-		{Kind: core.KindAudio, Direction: core.DirectionRecvonly},
 	}
 
 	// TODO: return webrtc.SessionDescription
@@ -36,6 +36,8 @@ func crealityClient(url string) (core.Producer, error) {
 		return nil, err
 	}
 
+	log.Trace().Msgf("[webrtc] offer:\n%s", offer)
+
 	body, err := offerToB64(offer)
 	if err != nil {
 		return nil, err
@@ -61,6 +63,12 @@ func crealityClient(url string) (core.Producer, error) {
 		return nil, err
 	}
 
+	log.Trace().Msgf("[webrtc] answer:\n%s", answer)
+
+	if answer, err = fixCrealitySDP(answer); err != nil {
+		return nil, err
+	}
+
 	if err = prod.SetAnswer(answer); err != nil {
 		return nil, err
 	}
@@ -108,3 +116,37 @@ func answerFromB64(r io.Reader) (string, error) {
 	// string "v=0..."
 	return v["sdp"], nil
 }
+
+func fixCrealitySDP(value string) (string, error) {
+	var sd sdp.SessionDescription
+	if err := sd.UnmarshalString(value); err != nil {
+		return "", err
+	}
+
+	md := sd.MediaDescriptions[0]
+
+	// important to skip first codec, because second codec will be used
+	skip := md.MediaName.Formats[0]
+	md.MediaName.Formats = md.MediaName.Formats[1:]
+
+	attrs := make([]sdp.Attribute, 0, len(md.Attributes))
+	for _, attr := range md.Attributes {
+		switch attr.Key {
+		case "fmtp", "rtpmap":
+			// important to skip fmtp with x-google, because this is second fmtp for same codec
+			// and pion library will fail parsing this SDP
+			if strings.HasPrefix(attr.Value, skip) || strings.Contains(attr.Value, "x-google") {
+				continue
+			}
+		}
+		attrs = append(attrs, attr)
+	}
+
+	md.Attributes = attrs
+
+	b, err := sd.Marshal()
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}

internal/webrtc/webrtc_test.go

@@ -2,6 +2,7 @@ package webrtc
 
 import (
 	"encoding/json"
+	"strings"
 	"testing"
 
 	"github.com/AlexxIT/go2rtc/internal/api/ws"
@@ -36,3 +37,37 @@ func TestWebRTCAPIv2(t *testing.T) {
 	require.Equal(t, "v=0\n...", offer.SDP)
 	require.Equal(t, "stun:stun.l.google.com:19302", offer.ICEServers[0].URLs[0])
 }
+
+func TestCrealitySDP(t *testing.T) {
+	sdp := `v=0
+o=- 1495799811084970 1495799811084970 IN IP4 0.0.0.0
+s=-
+t=0 0
+a=msid-semantic:WMS *
+a=group:BUNDLE 0
+m=video 9 UDP/TLS/RTP/SAVPF 96 98
+a=rtcp-fb:98 nack
+a=rtcp-fb:98 nack pli
+a=fmtp:96 profile-level-id=42e01f;level-asymmetry-allowed=1
+a=fmtp:98 profile-level-id=42e01f;packetization-mode=1;level-asymmetry-allowed=1
+a=fmtp:98 x-google-max-bitrate=6000;x-google-min-bitrate=2000;x-google-start-bitrate=4000
+a=rtpmap:96 H264/90000
+a=rtpmap:98 H264/90000
+a=ssrc:1 cname:pear
+c=IN IP4 0.0.0.0
+a=sendonly
+a=mid:0
+a=rtcp-mux
+a=ice-ufrag:7AVa
+a=ice-pwd:T+F/5y05Paw+mtG5Jrd8N3
+a=ice-options:trickle
+a=fingerprint:sha-256 A5:AB:C0:4E:29:5B:BD:3B:7D:88:24:6C:56:6B:2A:79:A3:76:99:35:57:75:AD:C8:5A:A6:34:20:88:1B:68:EF
+a=setup:passive
+a=candidate:1 1 UDP 2015363327 172.22.233.10 48929 typ host
+a=candidate:2 1 TCP 1015021823 172.22.233.10 0 typ host tcptype active
+a=candidate:3 1 TCP 1010827519 172.22.233.10 60677 typ host tcptype passive
+`
+	sdp, err := fixCrealitySDP(sdp)
+	require.Nil(t, err)
+	require.False(t, strings.Contains(sdp, "x-google-max-bitrate"))
+}