setCodecPreferences should accept codecs regardless of mimeType case

Ahmad-S792 · Ahmad Saleem · commit 34bbf22dba3f · 2026-02-09T01:14:57.000-08:00
https://bugs.webkit.org/show_bug.cgi?id=307157 rdar://169789074 Reviewed by Youenn Fablet. This patch aligns WebKit with Gecko / Firefox. Use case-insensitive comparison when checking mimeType prefix in toRtpCodecCapability to accept codecs with any case variation (e.g., "video/VP8", "VIDEO/vp8", "Video/Vp8"). * Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCRtpTransceiverBackend.cpp: (WebCore::toRtpCodecCapability): * LayoutTests/imported/w3c/web-platform-tests/webrtc/RTCRtpTransceiver-setCodecPreferences-expected.txt: Progressions Canonical link: https://commits.webkit.org/307062@main
diff --git a/LayoutTests/imported/w3c/web-platform-tests/webrtc/RTCRtpTransceiver-setCodecPreferences-expected.txt b/LayoutTests/imported/w3c/web-platform-tests/webrtc/RTCRtpTransceiver-setCodecPreferences-expected.txt
@@ -21,6 +21,6 @@ PASS setCodecPreferences() can remove rtx
 PASS setCodecPreferences() can remove red
 PASS setCodecPreferences() can remove ulpfec
 PASS setCodecPreferences() filters on receiver and prefers receiver order
-FAIL setCodecPreferences should accept audio codecs regardless of mimeType case promise_test: Unhandled rejection with value: object "InvalidModificationError: RTCRtpCodecCapability bad mimeType"
-FAIL setCodecPreferences should accept video codecs regardless of mimeType case promise_test: Unhandled rejection with value: object "InvalidModificationError: RTCRtpCodecCapability bad mimeType"
+PASS setCodecPreferences should accept audio codecs regardless of mimeType case
+PASS setCodecPreferences should accept video codecs regardless of mimeType case
 
diff --git a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCRtpTransceiverBackend.cpp b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCRtpTransceiverBackend.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018 Apple Inc. All rights reserved.
+ * Copyright (C) 2018-2026 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -88,9 +88,9 @@ bool LibWebRTCRtpTransceiverBackend::stopped() const
 static inline ExceptionOr<webrtc::RtpCodecCapability> toRtpCodecCapability(const RTCRtpCodecCapability& codec)
 {
     webrtc::RtpCodecCapability rtcCodec;
-    if (codec.mimeType.startsWith("video/"_s))
+    if (codec.mimeType.startsWithIgnoringASCIICase("video/"_s))
         rtcCodec.kind = webrtc::MediaType::VIDEO;
-    else if (codec.mimeType.startsWith("audio/"_s))
+    else if (codec.mimeType.startsWithIgnoringASCIICase("audio/"_s))
         rtcCodec.kind = webrtc::MediaType::AUDIO;
     else
         return Exception { ExceptionCode::InvalidModificationError, "RTCRtpCodecCapability bad mimeType"_s };
