move codecs from SFU, add helper to convert to pion type

codecs/codecs.go

@@ -0,0 +1,225 @@
+// Copyright 2026 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package codecs
+
+import (
+	"strings"
+
+	"github.com/livekit/protocol/livekit"
+	"github.com/livekit/protocol/logger"
+	"github.com/pion/webrtc/v4"
+)
+
+var (
+	OpusCodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeOpus.String(),
+			ClockRate:   48000,
+			Channels:    2,
+			SDPFmtpLine: "minptime=10;useinbandfec=1",
+		},
+		PayloadType: 111,
+	}
+
+	RedCodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeRED.String(),
+			ClockRate:   48000,
+			Channels:    2,
+			SDPFmtpLine: "111/111",
+		},
+		PayloadType: 63,
+	}
+
+	PCMUCodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypePCMU.String(),
+			ClockRate: 8000,
+		},
+		PayloadType: 0,
+	}
+
+	PCMACodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypePCMA.String(),
+			ClockRate: 8000,
+		},
+		PayloadType: 8,
+	}
+
+	VideoRTXCodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypeRTX.String(),
+			ClockRate: 90000,
+		},
+	}
+
+	VP8CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypeVP8.String(),
+			ClockRate: 90000,
+		},
+		PayloadType: 96,
+	}
+
+	VP9ProfileId0CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeVP9.String(),
+			ClockRate:   90000,
+			SDPFmtpLine: "profile-id=0",
+		},
+		PayloadType: 98,
+	}
+
+	VP9ProfileId1CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeVP9.String(),
+			ClockRate:   90000,
+			SDPFmtpLine: "profile-id=1",
+		},
+		PayloadType: 100,
+	}
+
+	H264ProfileLevelId42e01fPacketizationMode0CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeH264.String(),
+			ClockRate:   90000,
+			SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f",
+		},
+		PayloadType: 125,
+	}
+
+	H264ProfileLevelId42e01fPacketizationMode1CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeH264.String(),
+			ClockRate:   90000,
+			SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f",
+		},
+		PayloadType: 108,
+	}
+
+	H264HighProfileFmtp            = "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640032"
+	H264HighProfileCodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:    MimeTypeH264.String(),
+			ClockRate:   90000,
+			SDPFmtpLine: H264HighProfileFmtp,
+		},
+		PayloadType: 123,
+	}
+
+	AV1CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypeAV1.String(),
+			ClockRate: 90000,
+		},
+		PayloadType: 35,
+	}
+
+	H265CodecParameters = webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{
+			MimeType:  MimeTypeH265.String(),
+			ClockRate: 90000,
+		},
+		PayloadType: 116,
+	}
+
+	VideoCodecsParameters = []webrtc.RTPCodecParameters{
+		VP8CodecParameters,
+		VP9ProfileId0CodecParameters,
+		VP9ProfileId1CodecParameters,
+		H264ProfileLevelId42e01fPacketizationMode0CodecParameters,
+		H264ProfileLevelId42e01fPacketizationMode1CodecParameters,
+		H264HighProfileCodecParameters,
+		AV1CodecParameters,
+		H265CodecParameters,
+	}
+)
+
+func areFmtpLinesEqual(a, b string) bool {
+	if a == b {
+		return true
+	}
+
+	paramsA := make(map[string]string)
+	for _, param := range strings.Split(a, ";") {
+		if key, value, found := strings.Cut(param, "="); found {
+			paramsA[key] = value
+		}
+	}
+
+	count := 0
+	for _, param := range strings.Split(b, ";") {
+		if key, value, found := strings.Cut(param, "="); found {
+			if paramsA[key] != value {
+				return false
+			}
+			count++
+		}
+	}
+	return count == len(paramsA)
+}
+
+func ToWebrtcCodecParameters(codec *livekit.Codec) webrtc.RTPCodecParameters {
+	fmtp := codec.GetFmtpLine()
+	var params webrtc.RTPCodecParameters
+
+	switch NormalizeMimeType(codec.GetMime()) {
+	case MimeTypeOpus:
+		params = OpusCodecParameters
+	case MimeTypeRED:
+		params = RedCodecParameters
+	case MimeTypePCMU:
+		params = PCMUCodecParameters
+	case MimeTypePCMA:
+		params = PCMACodecParameters
+	case MimeTypeRTX:
+		params = VideoRTXCodecParameters
+	case MimeTypeVP8:
+		params = VP8CodecParameters
+	case MimeTypeVP9:
+		if strings.Contains(fmtp, "profile-id=1") {
+			params = VP9ProfileId1CodecParameters
+		} else {
+			params = VP9ProfileId0CodecParameters
+		}
+	case MimeTypeAV1:
+		params = AV1CodecParameters
+	case MimeTypeH264:
+		if strings.Contains(fmtp, "profile-level-id=640032") {
+			params = H264HighProfileCodecParameters
+		} else if strings.Contains(fmtp, "packetization-mode=0") {
+			params = H264ProfileLevelId42e01fPacketizationMode0CodecParameters
+		} else {
+			params = H264ProfileLevelId42e01fPacketizationMode1CodecParameters
+		}
+	case MimeTypeH265:
+		params = H265CodecParameters
+	default:
+		return webrtc.RTPCodecParameters{}
+	}
+
+	if fmtp != "" && !areFmtpLinesEqual(fmtp, params.SDPFmtpLine) {
+		logger.Warnw("non-standard fmtp, may not be supported",
+			nil,
+			"mime", codec.GetMime(),
+			"fmtp", fmtp,
+			"supportedFmtp", params.SDPFmtpLine,
+		)
+		params.SDPFmtpLine = fmtp
+	}
+
+	return params
+}