snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

internal/fmtp/h264.go

@@ -0,0 +1,86 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package fmtp
+
+import (
+	"encoding/hex"
+)
+
+func profileLevelIDMatches(a, b string) bool {
+	aa, err := hex.DecodeString(a)
+	if err != nil || len(aa) < 2 {
+		return false
+	}
+	bb, err := hex.DecodeString(b)
+	if err != nil || len(bb) < 2 {
+		return false
+	}
+
+	return aa[0] == bb[0] && aa[1] == bb[1]
+}
+
+type h264FMTP struct {
+	parameters map[string]string
+}
+
+func (h *h264FMTP) MimeType() string {
+	return "video/h264"
+}
+
+// Match returns true if h and b are compatible fmtp descriptions
+// Based on RFC6184 Section 8.2.2:
+//
+//	The parameters identifying a media format configuration for H.264
+//	are profile-level-id and packetization-mode.  These media format
+//	configuration parameters (except for the level part of profile-
+//	level-id) MUST be used symmetrically; that is, the answerer MUST
+//	either maintain all configuration parameters or remove the media
+//	format (payload type) completely if one or more of the parameter
+//	values are not supported.
+//	  Informative note: The requirement for symmetric use does not
+//	  apply for the level part of profile-level-id and does not apply
+//	  for the other stream properties and capability parameters.
+func (h *h264FMTP) Match(b FMTP) bool {
+	fmtp, ok := b.(*h264FMTP)
+	if !ok {
+		return false
+	}
+
+	// test packetization-mode
+	hpmode, hok := h.parameters["packetization-mode"]
+	if !hok {
+		return false
+	}
+	cpmode, cok := fmtp.parameters["packetization-mode"]
+	if !cok {
+		return false
+	}
+
+	if hpmode != cpmode {
+		return false
+	}
+
+	// test profile-level-id
+	hplid, hok := h.parameters["profile-level-id"]
+	if !hok {
+		return false
+	}
+
+	cplid, cok := fmtp.parameters["profile-level-id"]
+	if !cok {
+		return false
+	}
+
+	if !profileLevelIDMatches(hplid, cplid) {
+		return false
+	}
+
+	return true
+}
+
+func (h *h264FMTP) Parameter(key string) (string, bool) {
+	v, ok := h.parameters[key]
+
+	return v, ok
+}