Set prefer codec created by remote sdp

If a transceiver is created by remote sdp, then set
prefer codec same as offer peer.
For pion's codec match, it will use exact match
first, and then partial match. If patial match
only, the partial match codecs will become
negotiated codes. So it will be set prefer codec
when only exist partial match. And has same payload.

Add test cast for this.

refer to https://www.w3.org/TR/webrtc/#bib-rfc8829

Author: cnderrauber

peerconnection.go

@@ -1064,6 +1064,20 @@ func (pc *PeerConnection) SetRemoteDescription(desc SessionDescription) error {
 				pc.mu.Lock()
 				pc.addRTPTransceiver(t)
 				pc.mu.Unlock()
+
+				// if transceiver is create by remote sdp, set prefer codec same as remote peer
+				if codecs, err := codecsFromMediaDescription(media); err == nil {
+					filteredCodecs := []RTPCodecParameters{}
+					for _, codec := range codecs {
+						if c, matchType := codecParametersFuzzySearch(codec, pc.api.mediaEngine.getCodecsByKind(kind)); matchType == codecMatchExact {
+							// if codec match exact, use payloadtype register to mediaengine
+							codec.PayloadType = c.PayloadType
+							filteredCodecs = append(filteredCodecs, codec)
+						}
+					}
+					_ = t.SetCodecPreferences(filteredCodecs)
+				}
+
 			case direction == RTPTransceiverDirectionRecvonly:
 				if t.Direction() == RTPTransceiverDirectionSendrecv {
 					t.setDirection(RTPTransceiverDirectionSendonly)

peerconnection_go_test.go

@@ -1433,3 +1433,124 @@ func TestPeerConnectionNilCallback(t *testing.T) {
 
 	assert.NoError(t, pc.Close())
 }
+
+func TestTransceiverCreatedByRemoteSdpHasSameCodecOrderAsRemote(t *testing.T) {
+	t.Run("Codec MatchExact", func(t *testing.T) { //nolint:dupl
+		const remoteSdp = `v=0
+o=- 4596489990601351948 2 IN IP4 127.0.0.1
+s=-
+t=0 0
+m=video 60323 UDP/TLS/RTP/SAVPF 98 94 106
+a=ice-ufrag:1/MvHwjAyVf27aLu
+a=ice-pwd:3dBU7cFOBl120v33cynDvN1E
+a=ice-options:google-ice
+a=fingerprint:sha-256 75:74:5A:A6:A4:E5:52:F4:A7:67:4C:01:C7:EE:91:3F:21:3D:A2:E3:53:7B:6F:30:86:F2:30:AA:65:FB:04:24
+a=mid:0
+a=rtpmap:98 H264/90000
+a=fmtp:98 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f
+a=rtpmap:94 VP8/90000
+a=rtpmap:106 H264/90000
+a=fmtp:106 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
+a=sendonly
+m=video 60323 UDP/TLS/RTP/SAVPF 108 98 125
+a=ice-ufrag:1/MvHwjAyVf27aLu
+a=ice-pwd:3dBU7cFOBl120v33cynDvN1E
+a=ice-options:google-ice
+a=fingerprint:sha-256 75:74:5A:A6:A4:E5:52:F4:A7:67:4C:01:C7:EE:91:3F:21:3D:A2:E3:53:7B:6F:30:86:F2:30:AA:65:FB:04:24
+a=mid:1
+a=rtpmap:98 H264/90000
+a=fmtp:98 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f
+a=rtpmap:108 VP8/90000
+a=sendonly
+a=rtpmap:125 H264/90000
+a=fmtp:125 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
+`
+		m := MediaEngine{}
+		assert.NoError(t, m.RegisterCodec(RTPCodecParameters{
+			RTPCodecCapability: RTPCodecCapability{MimeTypeVP8, 90000, 0, "", nil},
+			PayloadType:        94,
+		}, RTPCodecTypeVideo))
+		assert.NoError(t, m.RegisterCodec(RTPCodecParameters{
+			RTPCodecCapability: RTPCodecCapability{MimeTypeH264, 90000, 0, "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f", nil},
+			PayloadType:        98,
+		}, RTPCodecTypeVideo))
+
+		api := NewAPI(WithMediaEngine(&m))
+		pc, err := api.NewPeerConnection(Configuration{})
+		assert.NoError(t, err)
+		assert.NoError(t, pc.SetRemoteDescription(SessionDescription{
+			Type: SDPTypeOffer,
+			SDP:  remoteSdp,
+		}))
+		ans, _ := pc.CreateAnswer(nil)
+		assert.NoError(t, pc.SetLocalDescription(ans))
+		codecOfTr1 := pc.GetTransceivers()[0].getCodecs()[0]
+		codecs := pc.api.mediaEngine.getCodecsByKind(RTPCodecTypeVideo)
+		_, matchType := codecParametersFuzzySearch(codecOfTr1, codecs)
+		assert.Equal(t, codecMatchExact, matchType)
+		codecOfTr2 := pc.GetTransceivers()[1].getCodecs()[0]
+		_, matchType = codecParametersFuzzySearch(codecOfTr2, codecs)
+		assert.Equal(t, codecMatchExact, matchType)
+		assert.EqualValues(t, 94, codecOfTr2.PayloadType)
+		assert.NoError(t, pc.Close())
+	})
+
+	t.Run("Codec PartialExact Only", func(t *testing.T) { //nolint:dupl
+		const remoteSdp = `v=0
+o=- 4596489990601351948 2 IN IP4 127.0.0.1
+s=-
+t=0 0
+m=video 60323 UDP/TLS/RTP/SAVPF 98 106
+a=ice-ufrag:1/MvHwjAyVf27aLu
+a=ice-pwd:3dBU7cFOBl120v33cynDvN1E
+a=ice-options:google-ice
+a=fingerprint:sha-256 75:74:5A:A6:A4:E5:52:F4:A7:67:4C:01:C7:EE:91:3F:21:3D:A2:E3:53:7B:6F:30:86:F2:30:AA:65:FB:04:24
+a=mid:0
+a=rtpmap:98 H264/90000
+a=fmtp:98 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
+a=rtpmap:106 H264/90000
+a=fmtp:106 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640032
+a=sendonly
+m=video 60323 UDP/TLS/RTP/SAVPF 125 98
+a=ice-ufrag:1/MvHwjAyVf27aLu
+a=ice-pwd:3dBU7cFOBl120v33cynDvN1E
+a=ice-options:google-ice
+a=fingerprint:sha-256 75:74:5A:A6:A4:E5:52:F4:A7:67:4C:01:C7:EE:91:3F:21:3D:A2:E3:53:7B:6F:30:86:F2:30:AA:65:FB:04:24
+a=mid:1
+a=rtpmap:125 H264/90000
+a=fmtp:125 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640032
+a=rtpmap:98 H264/90000
+a=fmtp:98 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
+a=sendonly
+`
+		m := MediaEngine{}
+		assert.NoError(t, m.RegisterCodec(RTPCodecParameters{
+			RTPCodecCapability: RTPCodecCapability{MimeTypeVP8, 90000, 0, "", nil},
+			PayloadType:        94,
+		}, RTPCodecTypeVideo))
+		assert.NoError(t, m.RegisterCodec(RTPCodecParameters{
+			RTPCodecCapability: RTPCodecCapability{MimeTypeH264, 90000, 0, "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f", nil},
+			PayloadType:        98,
+		}, RTPCodecTypeVideo))
+
+		api := NewAPI(WithMediaEngine(&m))
+		pc, err := api.NewPeerConnection(Configuration{})
+		assert.NoError(t, err)
+		assert.NoError(t, pc.SetRemoteDescription(SessionDescription{
+			Type: SDPTypeOffer,
+			SDP:  remoteSdp,
+		}))
+		ans, _ := pc.CreateAnswer(nil)
+		assert.NoError(t, pc.SetLocalDescription(ans))
+		codecOfTr1 := pc.GetTransceivers()[0].getCodecs()[0]
+		codecs := pc.api.mediaEngine.getCodecsByKind(RTPCodecTypeVideo)
+		_, matchType := codecParametersFuzzySearch(codecOfTr1, codecs)
+		assert.Equal(t, codecMatchExact, matchType)
+		codecOfTr2 := pc.GetTransceivers()[1].getCodecs()[0]
+		_, matchType = codecParametersFuzzySearch(codecOfTr2, codecs)
+		assert.Equal(t, codecMatchExact, matchType)
+		// h.264/profile-id=640032 should be remap to 106 as same as transceiver 1
+		assert.EqualValues(t, 106, codecOfTr2.PayloadType)
+		assert.NoError(t, pc.Close())
+	})
+}

peerconnection_media_test.go

@@ -129,6 +129,9 @@ func TestPeerConnection_Media_Sample(t *testing.T) {
 	go func() {
 		for {
 			time.Sleep(time.Millisecond * 100)
+			if pcOffer.ICEConnectionState() != ICEConnectionStateConnected {
+				continue
+			}
 			if routineErr := vp8Track.WriteSample(media.Sample{Data: []byte{0x00}, Duration: time.Second}); routineErr != nil {
 				fmt.Println(routineErr)
 			}