webrtc wpt: add test for codecs in subsequent offers
Asserting the "and also MUST include all currently available formats"
https://www.rfc-editor.org/rfc/rfc8829.html#name-subsequent-offers
See https://github.com/w3c/webrtc-pc/issues/2938
BUG=None
Change-Id: I7748ea94e58ba93cdf1043ee0235a7e560e260e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5293377
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1262601}
diff --git a/webrtc/protocol/codecs-subsequent-offer.https.html b/webrtc/protocol/codecs-subsequent-offer.https.html
new file mode 100644
index 0000000..fc9240e
--- /dev/null
+++ b/webrtc/protocol/codecs-subsequent-offer.https.html
@@ -0,0 +1,50 @@
+<!doctype html>
+<meta charset=utf-8>
+<meta name="timeout" content="long">
+<title>RTCPeerConnection Codecs in subsequent offer</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../third_party/sdp/sdp.js"></script>
+<script>
+'use strict';
+
+// A test for https://www.rfc-editor.org/rfc/rfc8829.html#name-subsequent-offers
+// The "m=" line and corresponding "a=rtpmap" and "a=fmtp" lines MUST only include
+// media formats that have not been excluded by the codec preferences of the
+// associated transceiver and also MUST include all currently available formats.
+
+// A VP8-only offer.
+const sdp = `v=0
+o=- 0 3 IN IP4 127.0.0.1
+s=-
+t=0 0
+a=fingerprint:sha-256 A7:24:72:CA:6E:02:55:39:BA:66:DF:6E:CC:4C:D8:B0:1A:BF:1A:56:65:7D:F4:03:AD:7E:77:43:2A:29:EC:93
+m=video 9 RTP/SAVPF 100
+c=IN IP4 0.0.0.0
+a=rtcp-mux
+a=sendrecv
+a=mid:video
+a=rtpmap:100 VP8/90000
+a=setup:actpass
+a=ice-ufrag:ETEn
+a=ice-pwd:OtSK0WpNtpUjkY4+86js7Z/l
+`;
+
+promise_test(async t => {
+ const pc = new RTCPeerConnection();
+ t.add_cleanup(() => pc.close());
+
+ await pc.setRemoteDescription({type: 'offer', sdp});
+ await pc.setLocalDescription();
+ const transceiver = pc.getTransceivers()[0];
+ assert_not_equals(transceiver.stopped, true);
+ const offer = await pc.createOffer();
+ const mediaSection = SDPUtils.getMediaSections(offer.sdp)[0];
+ const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
+ const vp8 = rtpParameters.codecs.filter(codec => codec.name === 'VP8');
+ const h264 = rtpParameters.codecs.filter(codec => codec.name === 'H264');
+ assert_greater_than(vp8.length, 0);
+ assert_greater_than(h264.length, 0);
+}, 'A subsequent offer after a VP8-only negotiation includes at least all mandatory to implement codecs');
+
+</script>
