Add support for sending abs-capture-time RTP extension

lib/handlers/Chrome74.js

@@ -215,7 +215,25 @@ class Chrome74 extends HandlerInterface_1.HandlerInterface {
         });
         let offer = await this._pc.createOffer();
         let localSdpObject = sdpTransform.parse(offer.sdp);
-        let offerMediaObject;
+        let offerMediaObject = localSdpObject.media[mediaSectionIdx.idx];
+        // May force abs-capture-time RTP extension negotiation.
+        {
+            const exten = sdpCommonUtils.addRtpExtensionToMediaObject({
+                mediaObject: offerMediaObject,
+                uri: 'http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time'
+            });
+            if (exten) {
+                offer = { type: 'offer', sdp: sdpTransform.write(localSdpObject) };
+                sdpCommonUtils.addRtpExtensionToRtpParameters({
+                    rtpParameters: sendingRtpParameters,
+                    extension: exten
+                });
+                sdpCommonUtils.addRtpExtensionToRtpParameters({
+                    rtpParameters: sendingRemoteRtpParameters,
+                    extension: exten
+                });
+            }
+        }
         if (!this._transportReady) {
             await this._setupTransport({
                 localDtlsRole: (_a = this._forcedLocalDtlsRole) !== null && _a !== void 0 ? _a : 'client',

lib/handlers/sdp/commonUtils.d.ts

@@ -1,5 +1,5 @@
 import { DtlsParameters } from '../../Transport';
-import { RtpCapabilities, RtpParameters } from '../../RtpParameters';
+import { RtpCapabilities, RtpHeaderExtensionParameters, RtpParameters } from '../../RtpParameters';
 export declare function extractRtpCapabilities({ sdpObject }: {
     sdpObject: any;
 }): RtpCapabilities;
@@ -17,4 +17,24 @@ export declare function applyCodecParameters({ offerRtpParameters, answerMediaOb
     offerRtpParameters: RtpParameters;
     answerMediaObject: any;
 }): void;
+/**
+ * Adds the given RTP extension to the given SDP media object and returns a
+ * RtpHeaderExtensionParameters object.
+ * If the extension is already present, this function doesn't add anything and
+ * doesn't return anything.
+ */
+export declare function addRtpExtensionToMediaObject({ mediaObject, uri }: {
+    mediaObject: any;
+    uri: string;
+}): RtpHeaderExtensionParameters | undefined;
+/**
+ * Adds the given RTP extension to the given RTP parameters.
+ * If the extension is already present (with same id), this function doesn't
+ * add anything. If the extension is present with a different id, then existing
+ * one is removed and the new one is added.
+ */
+export declare function addRtpExtensionToRtpParameters({ rtpParameters, extension }: {
+    rtpParameters: RtpParameters;
+    extension: RtpHeaderExtensionParameters;
+}): void;
 //# sourceMappingURL=commonUtils.d.ts.map

lib/handlers/sdp/commonUtils.js

@@ -23,7 +23,7 @@ var __importStar = (this && this.__importStar) || function (mod) {
     return result;
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.applyCodecParameters = exports.getCname = exports.extractDtlsParameters = exports.extractRtpCapabilities = void 0;
+exports.addRtpExtensionToRtpParameters = exports.addRtpExtensionToMediaObject = exports.applyCodecParameters = exports.getCname = exports.extractDtlsParameters = exports.extractRtpCapabilities = void 0;
 const sdpTransform = __importStar(require("sdp-transform"));
 function extractRtpCapabilities({ sdpObject }) {
     // Map of RtpCodecParameters indexed by payload type.
@@ -192,3 +192,55 @@ function applyCodecParameters({ offerRtpParameters, answerMediaObject }) {
     }
 }
 exports.applyCodecParameters = applyCodecParameters;
+/**
+ * Adds the given RTP extension to the given SDP media object and returns a
+ * RtpHeaderExtensionParameters object.
+ * If the extension is already present, this function doesn't add anything and
+ * doesn't return anything.
+ */
+function addRtpExtensionToMediaObject({ mediaObject, uri }) {
+    if (!Array.isArray(mediaObject.ext)) {
+        mediaObject.ext = [];
+    }
+    let id = 1;
+    for (const exten of mediaObject.ext) {
+        // If extension uri is already present, don't do anything.
+        if (exten.uri === uri) {
+            id = 0;
+            break;
+        }
+        if (exten.value >= id)
+            id = exten.value + 1;
+    }
+    if (id > 0) {
+        mediaObject.ext.push({ value: id, uri });
+        // NOTE: No support for encrypt/parameters fields.
+        return { uri, id };
+    }
+}
+exports.addRtpExtensionToMediaObject = addRtpExtensionToMediaObject;
+/**
+ * Adds the given RTP extension to the given RTP parameters.
+ * If the extension is already present (with same id), this function doesn't
+ * add anything. If the extension is present with a different id, then existing
+ * one is removed and the new one is added.
+ */
+function addRtpExtensionToRtpParameters({ rtpParameters, extension }) {
+    if (!Array.isArray(rtpParameters.headerExtensions)) {
+        rtpParameters.headerExtensions = [];
+    }
+    let replaced = false;
+    for (const exten of rtpParameters.headerExtensions) {
+        if (exten.uri === extension.uri && exten.id === extension.id) {
+            return;
+        }
+        else if (exten.uri === extension.uri && exten.id !== extension.id) {
+            exten.id = extension.id;
+            replaced = true;
+        }
+    }
+    if (!replaced) {
+        rtpParameters.headerExtensions.push(extension);
+    }
+}
+exports.addRtpExtensionToRtpParameters = addRtpExtensionToRtpParameters;

src/handlers/Chrome74.ts

@@ -324,7 +324,33 @@ export class Chrome74 extends HandlerInterface
 			});
 		let offer = await this._pc.createOffer();
 		let localSdpObject = sdpTransform.parse(offer.sdp);
-		let offerMediaObject;
+		let offerMediaObject = localSdpObject.media[mediaSectionIdx.idx];
+
+		// May force abs-capture-time RTP extension negotiation.
+		{
+			const exten = sdpCommonUtils.addRtpExtensionToMediaObject(
+				{
+					mediaObject : offerMediaObject,
+					uri         : 'http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time'
+				});
+
+			if (exten)
+			{
+				offer = { type: 'offer', sdp: sdpTransform.write(localSdpObject) };
+
+				sdpCommonUtils.addRtpExtensionToRtpParameters(
+					{
+						rtpParameters : sendingRtpParameters,
+						extension     : exten
+					});
+
+				sdpCommonUtils.addRtpExtensionToRtpParameters(
+					{
+						rtpParameters : sendingRemoteRtpParameters,
+						extension     : exten
+					});
+			}
+		}
 
 		if (!this._transportReady)
 		{

src/handlers/sdp/commonUtils.ts

@@ -4,6 +4,7 @@ import {
 	RtpCapabilities,
 	RtpCodecCapability,
 	RtpHeaderExtension,
+	RtpHeaderExtensionParameters,
 	RtpParameters,
 	RtcpFeedback
 } from '../../RtpParameters';
@@ -257,3 +258,88 @@ export function applyCodecParameters(
 		}
 	}
 }
+
+/**
+ * Adds the given RTP extension to the given SDP media object and returns a
+ * RtpHeaderExtensionParameters object.
+ * If the extension is already present, this function doesn't add anything and
+ * doesn't return anything.
+ */
+export function addRtpExtensionToMediaObject(
+	{ mediaObject, uri }:
+	{ mediaObject: any; uri: string }
+): RtpHeaderExtensionParameters | undefined
+{
+	if (!Array.isArray(mediaObject.ext))
+	{
+		mediaObject.ext = [];
+	}
+
+	let id = 1;
+
+	for (const exten of mediaObject.ext)
+	{
+		// If extension uri is already present, don't do anything.
+		if (exten.uri === uri)
+		{
+			id = 0;
+
+			break;
+		}
+
+		if (exten.value >= id)
+			id = exten.value + 1;
+	}
+
+	if (id > 0)
+	{
+		mediaObject.ext.push({ value: id, uri });
+
+		// NOTE: No support for encrypt/parameters fields.
+		return { uri,	id };
+	}
+}
+
+/**
+ * Adds the given RTP extension to the given RTP parameters.
+ * If the extension is already present (with same id), this function doesn't
+ * add anything. If the extension is present with a different id, then existing
+ * one is removed and the new one is added.
+ */
+export function addRtpExtensionToRtpParameters(
+	{
+		rtpParameters,
+		extension
+	}:
+	{
+		rtpParameters: RtpParameters;
+		extension: RtpHeaderExtensionParameters;
+	}
+): void
+{
+	if (!Array.isArray(rtpParameters.headerExtensions))
+	{
+		rtpParameters.headerExtensions = [];
+	}
+
+	let replaced = false;
+
+	for (const exten of rtpParameters.headerExtensions)
+	{
+		if (exten.uri === extension.uri && exten.id === extension.id)
+		{
+			return;
+		}
+		else if (exten.uri === extension.uri && exten.id !== extension.id)
+		{
+			exten.id = extension.id;
+
+			replaced = true;
+		}
+	}
+
+	if (!replaced)
+	{
+		rtpParameters.headerExtensions.push(extension);
+	}
+}