From 50145028dd7c67f297fd56603eaa28d88344fec4 Mon Sep 17 00:00:00 2001
From: Alex Snyatkov <snyatkov@amazon.com>
Date: Thu, 26 Mar 2026 22:28:45 +0000
Subject: [PATCH] Export GetCodecMap for payload lookups

Rename buildCodecMap to GetCodecMap so callers can
build the codec map once and reuse it for multiple
payload type lookups.

This is needed by pion/webrtc's
codecsFromMediaDescription (sdp.go:1101), which
calls GetCodecForPayloadType in a loop
(sdp.go:1112), rebuilding the full codec map on
every iteration. With GetCodecMap exported, webrtc
can build the map once and do direct lookups.
---
 util.go      | 11 +++++++----
 util_test.go |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/util.go b/util.go
index b6f6a98..c68fb50 100644
--- a/util.go
+++ b/util.go
@@ -226,7 +226,10 @@ func mergeCodecs(codec Codec, codecs map[uint8]Codec) {
 	codecs[savedCodec.PayloadType] = savedCodec
 }
 
-func (s *SessionDescription) buildCodecMap() map[uint8]Codec { //nolint:cyclop
+// GetCodecMap parses the SessionDescription and returns a map of payload
+// type to Codec. This allows callers to build the map once and look up
+// multiple payload types without rebuilding it each time.
+func (s *SessionDescription) GetCodecMap() map[uint8]Codec { //nolint:cyclop
 	codecs := map[uint8]Codec{
 		// static codecs that do not require a rtpmap
 		0: {
@@ -326,7 +329,7 @@ func codecsMatch(wanted, got Codec) bool {
 
 // GetCodecForPayloadType scans the SessionDescription for the given payload type and returns the codec.
 func (s *SessionDescription) GetCodecForPayloadType(payloadType uint8) (Codec, error) {
-	codecs := s.buildCodecMap()
+	codecs := s.GetCodecMap()
 
 	codec, ok := codecs[payloadType]
 	if ok {
@@ -337,7 +340,7 @@ func (s *SessionDescription) GetCodecForPayloadType(payloadType uint8) (Codec, e
 }
 
 func (s *SessionDescription) GetCodecsForPayloadTypes(payloadTypes []uint8) ([]Codec, error) {
-	codecs := s.buildCodecMap()
+	codecs := s.GetCodecMap()
 
 	result := make([]Codec, 0, len(payloadTypes))
 	for _, payloadType := range payloadTypes {
@@ -353,7 +356,7 @@ func (s *SessionDescription) GetCodecsForPayloadTypes(payloadTypes []uint8) ([]C
 // GetPayloadTypeForCodec scans the SessionDescription for a codec that matches the provided codec
 // as closely as possible and returns its payload type.
 func (s *SessionDescription) GetPayloadTypeForCodec(wanted Codec) (uint8, error) {
-	codecs := s.buildCodecMap()
+	codecs := s.GetCodecMap()
 
 	for payloadType, codec := range codecs {
 		if codecsMatch(wanted, codec) {
diff --git a/util_test.go b/util_test.go
index 1f1d82c..cf53027 100644
--- a/util_test.go
+++ b/util_test.go
@@ -437,7 +437,7 @@ func TestBuildCodecMap_RtcpFbError(t *testing.T) {
 		},
 	}
 
-	codecs := sd.buildCodecMap()
+	codecs := sd.GetCodecMap()
 
 	// the three static codecs should be present, unchanged.
 	if assert.Len(t, codecs, 3) {