rtsp: fixup sdp media type returned by TP-LINK camera

Related: https://github.com/aler9/mediamtx/issues/990

cmd/rtsp/rtsp.go

@@ -1,6 +1,10 @@
 package rtsp
 
 import (
+	"net"
+	"net/url"
+	"strings"
+
 	"github.com/AlexxIT/go2rtc/cmd/app"
 	"github.com/AlexxIT/go2rtc/cmd/streams"
 	"github.com/AlexxIT/go2rtc/pkg/core"
@@ -8,9 +12,6 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/rtsp"
 	"github.com/AlexxIT/go2rtc/pkg/tcp"
 	"github.com/rs/zerolog"
-	"net"
-	"net/url"
-	"strings"
 )
 
 func Init() {
@@ -123,6 +124,7 @@ func rtspHandler(url string) (core.Producer, error) {
 		if !backchannel {
 			return nil, err
 		}
+		log.Trace().Msgf("[rtsp] describe (backchannel=%t) err: %v", backchannel, err)
 
 		// second try without backchannel, we need to reconnect
 		conn.Backchannel = false

pkg/rtsp/helpers.go

@@ -2,14 +2,15 @@ package rtsp
 
 import (
 	"bytes"
-	"github.com/AlexxIT/go2rtc/pkg/core"
-	"github.com/pion/rtcp"
-	"github.com/pion/sdp/v3"
 	"io"
 	"net/url"
 	"regexp"
 	"strconv"
 	"strings"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtcp"
+	"github.com/pion/sdp/v3"
 )
 
 type RTCP struct {
@@ -35,6 +36,10 @@ func UnmarshalSDP(rawSDP []byte) ([]*core.Media, error) {
 			rawSDP = append([]byte(sdpHeader), rawSDP[i:]...)
 		}
 
+		// Fix invalid media type (errSDPInvalidValue) caused by
+		// some TP-LINK IP camera, e.g. TL-IPC44GW
+		rawSDP = bytes.ReplaceAll(rawSDP, []byte("m=application/TP-LINK "), []byte("m=application "))
+
 		if err == io.EOF {
 			rawSDP = append(rawSDP, '\n')
 		}