From e66f52b02d370116cbaf8dab286c87fcb379a83d Mon Sep 17 00:00:00 2001
From: Jianjun Zhu <jianjun.zhu@intel.com>
Date: Mon, 26 Apr 2021 10:58:25 +0800
Subject: [PATCH 1/5] Add new properties for getting senders and receivers.

---
 docs/design/owt_with_webrtc_apis.md |  4 ++--
 docs/mdfiles/changelog.md           |  2 ++
 src/sdk/base/publication.js         | 29 ++++++++++++++++++++++-
 src/sdk/conference/channel.js       | 36 +++++++++++++++++++----------
 src/sdk/conference/subscription.js  | 29 ++++++++++++++++++++++-
 5 files changed, 84 insertions(+), 16 deletions(-)

diff --git a/docs/design/owt_with_webrtc_apis.md b/docs/design/owt_with_webrtc_apis.md
index 351a1c28..c6e12753 100644
--- a/docs/design/owt_with_webrtc_apis.md
+++ b/docs/design/owt_with_webrtc_apis.md
@@ -9,8 +9,8 @@ OWT(Open WebRTC Toolkit) Client SDKs provide convenient APIs to create, publish,
 - Set preferred codecs.
 - Disable or enable RTX / RED / FEC.
 #### API Changes
-- A new method `getSender` will be added to `Publication`. It returns an `RTCRtpSender` for certain `Publication`.
-- A new method `getReceiver` will be added to `Subscription`. It returns an `RTCRtpReceiver` for certain `Subscription`.
+- A new member `senders` will be added to `Publication`. It returns an array of `RTCRtpSender`s for certain `Publication`.
+- A new member `receivers` will be added to `Subscription`. It returns an array `RTCRtpReceiver`s for certain `Subscription`.
 - A new method `addTransceiver(DOMString trackKind, sequence<RTCRtpEncodingParameters> sendEncodings)` will be added to `ConferenceClient`. It invokes `RTCPeerConnection.addTransceiver(trackKind, {direction:inactive, sendEncodings:sendEncodings})`, returns an `RTCRtpTransceiver`. Please note that direction is `inactive` until a `publish` with return transceiver is called.
 - The second parameter of `ConferenceClient.publish` accepts an `RTCRtpTransceiver` created by `RTCPeerConnection.addTransceiver`. When this method is called, certain `RTCRtpTransceiver`'s direction is changed to `sendonly`, and its sender's `setStreams` is called with the first parameter's `mediaStream`.
 #### Server Requirements
diff --git a/docs/mdfiles/changelog.md b/docs/mdfiles/changelog.md
index 6d773b58..f3ca8511 100644
--- a/docs/mdfiles/changelog.md
+++ b/docs/mdfiles/changelog.md
@@ -2,6 +2,8 @@ Change Log
 ==========
 # 5.1
 * When subscribe a stream in conference mode, the subscribed MediaStream or BidirectionalStream is associated with a `Owt.Conference.Subscription` instead of a `Owt.Base.RemoteStream`. The `stream` property of a RemoteStream in conference mode is always undefined, while a new property `stream` is added to `Subscription`. It allows a RemoteStream to be subscribed multiple times, as well as subscribing audio and video tracks from different streams.
+* Add a new property `senders` to `Publication` for get `RTCRtpSender`s.
+* Add a new property `receivers` to `Subscription` for get `RTCRtpReceiver`s.
 # 5.0
 * Add WebTransport support for conference mode, see [this design doc](../../design/webtransport.md) for detailed information.
 * All publications and subscriptions for the same conference use the same `PeerConnection`.
diff --git a/src/sdk/base/publication.js b/src/sdk/base/publication.js
index 9fb18a88..facb5147 100644
--- a/src/sdk/base/publication.js
+++ b/src/sdk/base/publication.js
@@ -123,7 +123,7 @@ export class PublicationSettings {
  */
 export class Publication extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
-  constructor(id, stop, getStats, mute, unmute) {
+  constructor(id, transceivers, stop, getStats, mute, unmute) {
     super();
     /**
      * @member {string} id
@@ -135,6 +135,33 @@ export class Publication extends EventDispatcher {
       writable: false,
       value: id ? id : Utils.createUuid(),
     });
+    /**
+     * @member {RTCRtpTransceiver[]} _transceivers
+     * @instance
+     * @private
+     * @desc A list of RTCRtpTransceiver associated with this Publication.  For
+     * each RTCRtpTransceiver, it's `direction` should always be `sendonly`.
+     * @memberof Owt.Base.Publication
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
+     */
+    Object.defineProperty(this, '_transceivers', {
+      configurable: false,
+      writable: false,
+      value: transceivers,
+    });
+    /**
+     * @member {RTCRtpSenders[]} senders
+     * @instance
+     * @readonly
+     * @desc A list of RTCRtpSenders associated with this Publication.
+     * @memberof Owt.Base.Publication
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtpsender-interface|RTCRtpSender Interface of WebRTC 1.0}.
+     */
+    Object.defineProperty(this, 'senders', {
+      configurable: false,
+      writable: false,
+      value: Array.from(this._transceivers, (t) => t.sender),
+    });
     /**
      * @function stop
      * @instance
diff --git a/src/sdk/conference/channel.js b/src/sdk/conference/channel.js
index dcb35994..6b689c0d 100644
--- a/src/sdk/conference/channel.js
+++ b/src/sdk/conference/channel.js
@@ -876,12 +876,18 @@ export class ConferencePeerConnectionChannel extends EventDispatcher {
     const internalId = this._reverseIdMap.get(sessionId);
     if (this._subscribePromises.has(internalId)) {
       const mediaStream = this._remoteMediaStreams.get(sessionId);
-      const subscription = new Subscription(sessionId, mediaStream, () => {
-        this._unsubscribe(internalId);
-      }, () => this._getStats(),
-      (trackKind) => this._muteOrUnmute(sessionId, true, false, trackKind),
-      (trackKind) => this._muteOrUnmute(sessionId, false, false, trackKind),
-      (options) => this._applyOptions(sessionId, options));
+      const subscription = new Subscription(
+          sessionId, mediaStream,
+          Array.from(
+              this._subscribeTransceivers.get(internalId).transceivers,
+              (t) => t.transceiver),
+          () => {
+            this._unsubscribe(internalId);
+          },
+          () => this._getStats(),
+          (trackKind) => this._muteOrUnmute(sessionId, true, false, trackKind),
+          (trackKind) => this._muteOrUnmute(sessionId, false, false, trackKind),
+          (options) => this._applyOptions(sessionId, options));
       this._subscriptions.set(sessionId, subscription);
       // Resolve subscription if mediaStream is ready.
       if (this._subscriptions.get(sessionId).stream) {
@@ -889,12 +895,18 @@ export class ConferencePeerConnectionChannel extends EventDispatcher {
         this._subscribePromises.delete(internalId);
       }
     } else if (this._publishPromises.has(internalId)) {
-      const publication = new Publication(sessionId, () => {
-        this._unpublish(internalId);
-        return Promise.resolve();
-      }, () => this._getStats(),
-      (trackKind) => this._muteOrUnmute(sessionId, true, true, trackKind),
-      (trackKind) => this._muteOrUnmute(sessionId, false, true, trackKind));
+      const publication = new Publication(
+          sessionId,
+          Array.from(
+              this._publishTransceivers.get(internalId).transceivers,
+              (t) => t.transceiver),
+          () => {
+            this._unpublish(internalId);
+            return Promise.resolve();
+          },
+          () => this._getStats(),
+          (trackKind) => this._muteOrUnmute(sessionId, true, true, trackKind),
+          (trackKind) => this._muteOrUnmute(sessionId, false, true, trackKind));
       this._publications.set(sessionId, publication);
       this._publishPromises.get(internalId).resolve(publication);
       // Do not fire publication's ended event when associated stream is ended.
diff --git a/src/sdk/conference/subscription.js b/src/sdk/conference/subscription.js
index a8056dbe..ced81bf7 100644
--- a/src/sdk/conference/subscription.js
+++ b/src/sdk/conference/subscription.js
@@ -270,7 +270,8 @@ export class SubscriptionUpdateOptions {
  */
 export class Subscription extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
-  constructor(id, stream, stop, getStats, mute, unmute, applyOptions) {
+  constructor(
+      id, stream, transceivers, stop, getStats, mute, unmute, applyOptions) {
     super();
     if (!id) {
       throw new TypeError('ID cannot be null or undefined.');
@@ -298,6 +299,32 @@ export class Subscription extends EventDispatcher {
       writable: true,
       value: stream,
     });
+    /**
+     * @member {RTCRtpTransceiver[]} transceivers
+     * @instance
+     * @desc A list of RTCRtpTransceiver associated with this Subscription. For
+     * each RTCRtpTransceiver, it's `direction` should always be `recvonly`.
+     * @memberof Owt.Base.Subscription
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
+     */
+    Object.defineProperty(this, '_transceivers', {
+      configurable: false,
+      writable: false,
+      value: transceivers,
+    });
+    /**
+     * @member {RTCRtpReceivers[]} receivers
+     * @instance
+     * @readonly
+     * @desc A list of RTCRtpReceivers associated with this Subscription.
+     * @memberof Owt.Base.Subscription
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtpreceiver-interface|RTCRtpReceivers Interface of WebRTC 1.0}.
+     */
+    Object.defineProperty(this, 'receivers', {
+      configurable: false,
+      writable: false,
+      value: Array.from(this._transceivers, (t) => t.receiver),
+    });
     /**
      * @function stop
      * @instance

From 7299e1941aab2dd88d0d476d9dd8300f61aba64c Mon Sep 17 00:00:00 2001
From: Jianjun Zhu <jianjun.zhu@intel.com>
Date: Mon, 26 Apr 2021 12:47:15 +0800
Subject: [PATCH 2/5] Property senders is not available in P2P mode.

---
 src/sdk/base/publication.js           | 10 +++++++---
 src/sdk/p2p/peerconnection-channel.js |  3 ++-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/sdk/base/publication.js b/src/sdk/base/publication.js
index facb5147..55ea5f12 100644
--- a/src/sdk/base/publication.js
+++ b/src/sdk/base/publication.js
@@ -139,8 +139,9 @@ export class Publication extends EventDispatcher {
      * @member {RTCRtpTransceiver[]} _transceivers
      * @instance
      * @private
-     * @desc A list of RTCRtpTransceiver associated with this Publication.  For
+     * @desc A list of RTCRtpTransceiver associated with this Publication. For
      * each RTCRtpTransceiver, it's `direction` should always be `sendonly`.
+     * This member is not available in P2P mode.
      * @memberof Owt.Base.Publication
      * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
      */
@@ -153,14 +154,17 @@ export class Publication extends EventDispatcher {
      * @member {RTCRtpSenders[]} senders
      * @instance
      * @readonly
-     * @desc A list of RTCRtpSenders associated with this Publication.
+     * @desc A list of RTCRtpSenders associated with this Publication. This
+     * member is not available in P2P mode.
      * @memberof Owt.Base.Publication
      * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtpsender-interface|RTCRtpSender Interface of WebRTC 1.0}.
      */
     Object.defineProperty(this, 'senders', {
       configurable: false,
       writable: false,
-      value: Array.from(this._transceivers, (t) => t.sender),
+      value: this._transceivers ?
+          Array.from(this._transceivers, (t) => t.sender) :
+          undefined,
     });
     /**
      * @function stop
diff --git a/src/sdk/p2p/peerconnection-channel.js b/src/sdk/p2p/peerconnection-channel.js
index 3847ae71..76808c9b 100644
--- a/src/sdk/p2p/peerconnection-channel.js
+++ b/src/sdk/p2p/peerconnection-channel.js
@@ -305,8 +305,9 @@ class P2PPeerConnectionChannel extends EventDispatcher {
                 (element) => element.mediaStream.id == mediaStreamId);
             const targetStream = this._publishingStreams[targetStreamIndex];
             this._publishingStreams.splice(targetStreamIndex, 1);
+            // TODO: Set transceivers for Publication.
             const publication = new Publication(
-                id, () => {
+                id, undefined, () => {
                   this._unpublish(targetStream).then(() => {
                     publication.dispatchEvent(new OwtEvent('ended'));
                   }, (err) => {

From 1c158b5c8275b62522c5c34795f4dfb65b50c611 Mon Sep 17 00:00:00 2001
From: Jianjun Zhu <jianjun.zhu@intel.com>
Date: Mon, 26 Apr 2021 14:54:39 +0800
Subject: [PATCH 3/5] Add test cases.

---
 docs/mdfiles/changelog.md                 |  4 ++--
 test/unit/resources/scripts/base.js       | 14 +++++++++++++-
 test/unit/resources/scripts/conference.js | 14 +++++++++++++-
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/docs/mdfiles/changelog.md b/docs/mdfiles/changelog.md
index f3ca8511..15767808 100644
--- a/docs/mdfiles/changelog.md
+++ b/docs/mdfiles/changelog.md
@@ -2,8 +2,8 @@ Change Log
 ==========
 # 5.1
 * When subscribe a stream in conference mode, the subscribed MediaStream or BidirectionalStream is associated with a `Owt.Conference.Subscription` instead of a `Owt.Base.RemoteStream`. The `stream` property of a RemoteStream in conference mode is always undefined, while a new property `stream` is added to `Subscription`. It allows a RemoteStream to be subscribed multiple times, as well as subscribing audio and video tracks from different streams.
-* Add a new property `senders` to `Publication` for get `RTCRtpSender`s.
-* Add a new property `receivers` to `Subscription` for get `RTCRtpReceiver`s.
+* Add a new property `senders` to `Publication` for getting `RTCRtpSender`s.
+* Add a new property `receivers` to `Subscription` for getting `RTCRtpReceiver`s.
 # 5.0
 * Add WebTransport support for conference mode, see [this design doc](../../design/webtransport.md) for detailed information.
 * All publications and subscriptions for the same conference use the same `PeerConnection`.
diff --git a/test/unit/resources/scripts/base.js b/test/unit/resources/scripts/base.js
index 6978aad0..f5463ee4 100644
--- a/test/unit/resources/scripts/base.js
+++ b/test/unit/resources/scripts/base.js
@@ -8,9 +8,9 @@ import * as MediaStreamFactoryModule from '../../../../src/sdk/base/mediastream-
 import * as StreamModule from '../../../../src/sdk/base/stream.js';
 import * as MediaFormatModule from '../../../../src/sdk/base/mediaformat.js'
 import * as SdpUtils from '../../../../src/sdk/base/sdputils.js'
+import * as PublicationModule from '../../../../src/sdk/base/publication.js'
 
 const expect = chai.expect;
-const screenSharingExtensionId = 'jniliohjdiikfjjdlpapmngebedgigjn';
 chai.use(chaiAsPromised);
 describe('Unit tests for MediaStreamFactory', function() {
   function createMediaStream(constraints, audioTracksExpected,
@@ -181,3 +181,15 @@ describe('Unit tests for SDP utils.', function() {
     done();
   });
 });
+
+describe('Unit tests for Publication.', () => {
+  it('Get senders returns all transceivers\' sender.', () => {
+    const audioTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
+    const videoTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
+    const publication = new PublicationModule.Publication(
+        'sessionId', [audioTransceiver, videoTransceiver]);
+    expect(publication.senders).to.deep.equal([
+      audioTransceiver.sender, videoTransceiver.sender
+    ]);
+  });
+});
\ No newline at end of file
diff --git a/test/unit/resources/scripts/conference.js b/test/unit/resources/scripts/conference.js
index b34aa596..50efd629 100644
--- a/test/unit/resources/scripts/conference.js
+++ b/test/unit/resources/scripts/conference.js
@@ -8,9 +8,9 @@ import {ConferenceClient} from '../../../../src/sdk/conference/client.js';
 import {ConferencePeerConnectionChannel} from '../../../../src/sdk/conference/channel.js';
 import * as StreamModule from '../../../../src/sdk/base/stream.js';
 import * as EventModule from '../../../../src/sdk/base/event.js'
+import * as SubscriptionModule from '../../../../src/sdk/conference/subscription.js'
 
 const expect = chai.expect;
-const screenSharingExtensionId = 'jniliohjdiikfjjdlpapmngebedgigjn';
 chai.use(chaiAsPromised);
 
 describe('Unit tests for ConferenceClient', function() {
@@ -98,4 +98,16 @@ describe('Unit tests for ConferencePeerConnectionChannel.', () => {
       }
     });
   });
+});
+
+describe('Unit tests for Subscription.', () => {
+  it('Get receivers returns all transceivers\' receiver.', () => {
+    const audioTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
+    const videoTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
+    const Subscription = new SubscriptionModule.Subscription(
+        'sessionId', undefined, [audioTransceiver, videoTransceiver]);
+    expect(Subscription.receivers).to.deep.equal([
+      audioTransceiver.receiver, videoTransceiver.receiver
+    ]);
+  });
 });
\ No newline at end of file

From e4bb819a27a923d28edbe698e8fe0b3b39f77b68 Mon Sep 17 00:00:00 2001
From: Jianjun Zhu <jianjun.zhu@intel.com>
Date: Fri, 30 Apr 2021 15:37:09 +0800
Subject: [PATCH 4/5] Move transceivers to TransportSettings.

---
 docs/design/owt_with_webrtc_apis.md       |  4 ++--
 docs/mdfiles/changelog.md                 |  4 ++--
 src/sdk/base/publication.js               | 29 ++++-------------------
 src/sdk/base/transport.js                 | 17 ++++++++++---
 src/sdk/conference/channel.js             | 18 ++++++++------
 src/sdk/conference/subscription.js        | 26 +++++---------------
 test/unit/resources/scripts/base.js       | 14 +++++------
 test/unit/resources/scripts/conference.js | 15 ++++++------
 8 files changed, 54 insertions(+), 73 deletions(-)

diff --git a/docs/design/owt_with_webrtc_apis.md b/docs/design/owt_with_webrtc_apis.md
index c6e12753..43131541 100644
--- a/docs/design/owt_with_webrtc_apis.md
+++ b/docs/design/owt_with_webrtc_apis.md
@@ -9,8 +9,8 @@ OWT(Open WebRTC Toolkit) Client SDKs provide convenient APIs to create, publish,
 - Set preferred codecs.
 - Disable or enable RTX / RED / FEC.
 #### API Changes
-- A new member `senders` will be added to `Publication`. It returns an array of `RTCRtpSender`s for certain `Publication`.
-- A new member `receivers` will be added to `Subscription`. It returns an array `RTCRtpReceiver`s for certain `Subscription`.
+- A new member `rtpTransceivers` will be added to `TransportSettings`. It returns an array `RTCRtpReceiver`s for RTP transport.
+- A new member `transport` will be added to `Publication` and `Subscription`. Developers could get `RTPTransceiver`s from its `rtpTransceivers` property.
 - A new method `addTransceiver(DOMString trackKind, sequence<RTCRtpEncodingParameters> sendEncodings)` will be added to `ConferenceClient`. It invokes `RTCPeerConnection.addTransceiver(trackKind, {direction:inactive, sendEncodings:sendEncodings})`, returns an `RTCRtpTransceiver`. Please note that direction is `inactive` until a `publish` with return transceiver is called.
 - The second parameter of `ConferenceClient.publish` accepts an `RTCRtpTransceiver` created by `RTCPeerConnection.addTransceiver`. When this method is called, certain `RTCRtpTransceiver`'s direction is changed to `sendonly`, and its sender's `setStreams` is called with the first parameter's `mediaStream`.
 #### Server Requirements
diff --git a/docs/mdfiles/changelog.md b/docs/mdfiles/changelog.md
index 15767808..a4ded8a2 100644
--- a/docs/mdfiles/changelog.md
+++ b/docs/mdfiles/changelog.md
@@ -2,8 +2,8 @@ Change Log
 ==========
 # 5.1
 * When subscribe a stream in conference mode, the subscribed MediaStream or BidirectionalStream is associated with a `Owt.Conference.Subscription` instead of a `Owt.Base.RemoteStream`. The `stream` property of a RemoteStream in conference mode is always undefined, while a new property `stream` is added to `Subscription`. It allows a RemoteStream to be subscribed multiple times, as well as subscribing audio and video tracks from different streams.
-* Add a new property `senders` to `Publication` for getting `RTCRtpSender`s.
-* Add a new property `receivers` to `Subscription` for getting `RTCRtpReceiver`s.
+* Add a new property `transport` to `Publication` for getting `TransportSettings`.
+* Add a new property `rtpTransceivers` to `TransportSettings` and `TransportConstraints`.
 # 5.0
 * Add WebTransport support for conference mode, see [this design doc](../../design/webtransport.md) for detailed information.
 * All publications and subscriptions for the same conference use the same `PeerConnection`.
diff --git a/src/sdk/base/publication.js b/src/sdk/base/publication.js
index 55ea5f12..7ead125e 100644
--- a/src/sdk/base/publication.js
+++ b/src/sdk/base/publication.js
@@ -123,7 +123,7 @@ export class PublicationSettings {
  */
 export class Publication extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
-  constructor(id, transceivers, stop, getStats, mute, unmute) {
+  constructor(id, transport, stop, getStats, mute, unmute) {
     super();
     /**
      * @member {string} id
@@ -136,35 +136,16 @@ export class Publication extends EventDispatcher {
       value: id ? id : Utils.createUuid(),
     });
     /**
-     * @member {RTCRtpTransceiver[]} _transceivers
-     * @instance
-     * @private
-     * @desc A list of RTCRtpTransceiver associated with this Publication. For
-     * each RTCRtpTransceiver, it's `direction` should always be `sendonly`.
-     * This member is not available in P2P mode.
-     * @memberof Owt.Base.Publication
-     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
-     */
-    Object.defineProperty(this, '_transceivers', {
-      configurable: false,
-      writable: false,
-      value: transceivers,
-    });
-    /**
-     * @member {RTCRtpSenders[]} senders
+     * @member {Owt.Base.TransportSettings} transport
      * @instance
      * @readonly
-     * @desc A list of RTCRtpSenders associated with this Publication. This
-     * member is not available in P2P mode.
+     * @desc Transport settings for the publication.
      * @memberof Owt.Base.Publication
-     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtpsender-interface|RTCRtpSender Interface of WebRTC 1.0}.
      */
-    Object.defineProperty(this, 'senders', {
+    Object.defineProperty(this, 'transport', {
       configurable: false,
       writable: false,
-      value: this._transceivers ?
-          Array.from(this._transceivers, (t) => t.sender) :
-          undefined,
+      value: transport,
     });
     /**
      * @function stop
diff --git a/src/sdk/base/transport.js b/src/sdk/base/transport.js
index e79afbf4..3bb5a79a 100644
--- a/src/sdk/base/transport.js
+++ b/src/sdk/base/transport.js
@@ -56,18 +56,29 @@ export class TransportSettings {
   // eslint-disable-next-line require-jsdoc
   constructor(type, id) {
     /**
-     * @member {Array.<Owt.Base.TransportType>} type
+     * @member {Owt.Base.TransportType} type
      * @instance
-     * @memberof Owt.Base.TransportConstraints
+     * @memberof Owt.Base.TransportSettings
      * @desc Transport type for publication and subscription.
      */
     this.type = type;
     /**
      * @member {string} id
      * @instance
-     * @memberof Owt.Base.TransportConstraints
+     * @memberof Owt.Base.TransportSettings
      * @desc Transport ID.
      */
     this.id = id;
+
+    /**
+     * @member {?Array.<RTCRtpTransceiver>} rtpTransceivers
+     * @instance
+     * @memberof Owt.Base.TransportSettings
+     * @desc A list of RTCRtpTransceiver associated with the publication or
+     * subscription. It's only available in conference mode when TransportType
+     * is webrtc.
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
+     */
+    this.rtpTransceivers = undefined;
   }
 }
diff --git a/src/sdk/conference/channel.js b/src/sdk/conference/channel.js
index 6b689c0d..e142bfe7 100644
--- a/src/sdk/conference/channel.js
+++ b/src/sdk/conference/channel.js
@@ -21,6 +21,7 @@ import {Subscription} from './subscription.js';
 import {ConferenceError} from './error.js';
 import * as Utils from '../base/utils.js';
 import * as SdpUtils from '../base/sdputils.js';
+import {TransportSettings, TransportType} from '../base/transport.js';
 
 /**
  * @class ConferencePeerConnectionChannel
@@ -876,11 +877,12 @@ export class ConferencePeerConnectionChannel extends EventDispatcher {
     const internalId = this._reverseIdMap.get(sessionId);
     if (this._subscribePromises.has(internalId)) {
       const mediaStream = this._remoteMediaStreams.get(sessionId);
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, this._id);
+      transportSettings.rtpTransceivers =
+          this._subscribeTransceivers.get(internalId).transceivers;
       const subscription = new Subscription(
-          sessionId, mediaStream,
-          Array.from(
-              this._subscribeTransceivers.get(internalId).transceivers,
-              (t) => t.transceiver),
+          sessionId, mediaStream, transportSettings,
           () => {
             this._unsubscribe(internalId);
           },
@@ -895,11 +897,13 @@ export class ConferencePeerConnectionChannel extends EventDispatcher {
         this._subscribePromises.delete(internalId);
       }
     } else if (this._publishPromises.has(internalId)) {
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, this._id);
+      transportSettings.transceivers =
+          this._publishTransceivers.get(internalId).transceivers;
       const publication = new Publication(
           sessionId,
-          Array.from(
-              this._publishTransceivers.get(internalId).transceivers,
-              (t) => t.transceiver),
+          transportSettings,
           () => {
             this._unpublish(internalId);
             return Promise.resolve();
diff --git a/src/sdk/conference/subscription.js b/src/sdk/conference/subscription.js
index ced81bf7..f08cfdb6 100644
--- a/src/sdk/conference/subscription.js
+++ b/src/sdk/conference/subscription.js
@@ -271,7 +271,7 @@ export class SubscriptionUpdateOptions {
 export class Subscription extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
   constructor(
-      id, stream, transceivers, stop, getStats, mute, unmute, applyOptions) {
+      id, stream, transport, stop, getStats, mute, unmute, applyOptions) {
     super();
     if (!id) {
       throw new TypeError('ID cannot be null or undefined.');
@@ -300,30 +300,16 @@ export class Subscription extends EventDispatcher {
       value: stream,
     });
     /**
-     * @member {RTCRtpTransceiver[]} transceivers
-     * @instance
-     * @desc A list of RTCRtpTransceiver associated with this Subscription. For
-     * each RTCRtpTransceiver, it's `direction` should always be `recvonly`.
-     * @memberof Owt.Base.Subscription
-     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
-     */
-    Object.defineProperty(this, '_transceivers', {
-      configurable: false,
-      writable: false,
-      value: transceivers,
-    });
-    /**
-     * @member {RTCRtpReceivers[]} receivers
+     * @member {Owt.Base.TransportSettings} transport
      * @instance
      * @readonly
-     * @desc A list of RTCRtpReceivers associated with this Subscription.
-     * @memberof Owt.Base.Subscription
-     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtpreceiver-interface|RTCRtpReceivers Interface of WebRTC 1.0}.
+     * @desc Transport settings for the publication.
+     * @memberof Owt.Base.Publication
      */
-    Object.defineProperty(this, 'receivers', {
+    Object.defineProperty(this, 'transport', {
       configurable: false,
       writable: false,
-      value: Array.from(this._transceivers, (t) => t.receiver),
+      value: transport,
     });
     /**
      * @function stop
diff --git a/test/unit/resources/scripts/base.js b/test/unit/resources/scripts/base.js
index f5463ee4..faf6e921 100644
--- a/test/unit/resources/scripts/base.js
+++ b/test/unit/resources/scripts/base.js
@@ -184,12 +184,12 @@ describe('Unit tests for SDP utils.', function() {
 
 describe('Unit tests for Publication.', () => {
   it('Get senders returns all transceivers\' sender.', () => {
-    const audioTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
-    const videoTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
-    const publication = new PublicationModule.Publication(
-        'sessionId', [audioTransceiver, videoTransceiver]);
-    expect(publication.senders).to.deep.equal([
-      audioTransceiver.sender, videoTransceiver.sender
-    ]);
+    it('Get transport returns correct TransportSettings.', () => {
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, 'randomId');
+      const publication =
+          new PublicationModule.Publication('sessionId', transportSettings);
+      expect(publication.transport).to.equal(transportSettings);
+    });
   });
 });
\ No newline at end of file
diff --git a/test/unit/resources/scripts/conference.js b/test/unit/resources/scripts/conference.js
index 50efd629..1913e9be 100644
--- a/test/unit/resources/scripts/conference.js
+++ b/test/unit/resources/scripts/conference.js
@@ -9,6 +9,7 @@ import {ConferencePeerConnectionChannel} from '../../../../src/sdk/conference/ch
 import * as StreamModule from '../../../../src/sdk/base/stream.js';
 import * as EventModule from '../../../../src/sdk/base/event.js'
 import * as SubscriptionModule from '../../../../src/sdk/conference/subscription.js'
+import { TransportSettings, TransportType } from '../../../../src/sdk/base/transport.js';
 
 const expect = chai.expect;
 chai.use(chaiAsPromised);
@@ -101,13 +102,11 @@ describe('Unit tests for ConferencePeerConnectionChannel.', () => {
 });
 
 describe('Unit tests for Subscription.', () => {
-  it('Get receivers returns all transceivers\' receiver.', () => {
-    const audioTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
-    const videoTransceiver = {sender: new sinon.spy(), receiver: sinon.spy()};
-    const Subscription = new SubscriptionModule.Subscription(
-        'sessionId', undefined, [audioTransceiver, videoTransceiver]);
-    expect(Subscription.receivers).to.deep.equal([
-      audioTransceiver.receiver, videoTransceiver.receiver
-    ]);
+  it('Get transport returns correct TransportSettings.', () => {
+    const transportSettings =
+        new TransportSettings(TransportType.WEBRTC, 'randomId');
+    const subscription = new SubscriptionModule.Subscription(
+        'sessionId', undefined, transportSettings);
+    expect(subscription.transport).to.equal(transportSettings);
   });
 });
\ No newline at end of file

From 68c15b20a2d228ed6e12520c7fabfe490cafd2af Mon Sep 17 00:00:00 2001
From: Jianjun Zhu <jianjun.zhu@intel.com>
Date: Thu, 6 May 2021 10:33:56 +0800
Subject: [PATCH 5/5] Fix a typo.

---
 src/sdk/conference/subscription.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/sdk/conference/subscription.js b/src/sdk/conference/subscription.js
index f08cfdb6..16676f24 100644
--- a/src/sdk/conference/subscription.js
+++ b/src/sdk/conference/subscription.js
@@ -303,8 +303,8 @@ export class Subscription extends EventDispatcher {
      * @member {Owt.Base.TransportSettings} transport
      * @instance
      * @readonly
-     * @desc Transport settings for the publication.
-     * @memberof Owt.Base.Publication
+     * @desc Transport settings for the subscription.
+     * @memberof Owt.Base.Subscription
      */
     Object.defineProperty(this, 'transport', {
       configurable: false,