Allow setting of degradation preference (#420)

* Allow setting of degradation preference

* fix tests

* spotless

@@ -465,7 +465,6 @@ internal fun isSVCCodec(codec: String?): Boolean {
 /**
  * @suppress
  */
-@VisibleForTesting
 data class TrackBitrateInfo(
     val codec: String,
     val maxBitrate: Long,
@@ -474,7 +473,6 @@ data class TrackBitrateInfo(
 /**
  * @suppress
  */
-@VisibleForTesting
 sealed class TrackBitrateInfoKey {
     data class Cid(val value: String) : TrackBitrateInfoKey()
     data class Transceiver(val value: RtpTransceiver) : TrackBitrateInfoKey()

@@ -31,7 +31,19 @@ import io.livekit.android.room.DefaultsManager
 import io.livekit.android.room.RTCEngine
 import io.livekit.android.room.TrackBitrateInfo
 import io.livekit.android.room.isSVCCodec
-import io.livekit.android.room.track.*
+import io.livekit.android.room.track.DataPublishReliability
+import io.livekit.android.room.track.LocalAudioTrack
+import io.livekit.android.room.track.LocalAudioTrackOptions
+import io.livekit.android.room.track.LocalScreencastVideoTrack
+import io.livekit.android.room.track.LocalTrackPublication
+import io.livekit.android.room.track.LocalVideoTrack
+import io.livekit.android.room.track.LocalVideoTrackOptions
+import io.livekit.android.room.track.Track
+import io.livekit.android.room.track.TrackException
+import io.livekit.android.room.track.TrackPublication
+import io.livekit.android.room.track.VideoCaptureParameter
+import io.livekit.android.room.track.VideoCodec
+import io.livekit.android.room.track.VideoEncoding
 import io.livekit.android.room.util.EncodingUtils
 import io.livekit.android.util.LKLog
 import io.livekit.android.webrtc.sortVideoCodecPreferences
@@ -41,8 +53,14 @@ import livekit.LivekitModels
 import livekit.LivekitRtc
 import livekit.LivekitRtc.AddTrackRequest
 import livekit.LivekitRtc.SimulcastCodec
-import livekit.org.webrtc.*
+import livekit.org.webrtc.EglBase
+import livekit.org.webrtc.PeerConnectionFactory
+import livekit.org.webrtc.RtpParameters
+import livekit.org.webrtc.RtpTransceiver
 import livekit.org.webrtc.RtpTransceiver.RtpTransceiverInit
+import livekit.org.webrtc.SurfaceTextureHelper
+import livekit.org.webrtc.VideoCapturer
+import livekit.org.webrtc.VideoProcessor
 import javax.inject.Named
 import kotlin.math.max
 
@@ -412,10 +430,14 @@ internal constructor(
             }
         }
 
-        // Set preferred video codec order
         if (options is VideoTrackPublishOptions) {
+            // Set preferred video codec order
             transceiver.sortVideoCodecPreferences(options.videoCodec, capabilitiesGetter)
             (track as LocalVideoTrack).codec = options.videoCodec
+
+            val rtpParameters = transceiver.sender.parameters
+            rtpParameters.degradationPreference = options.degradationPreference
+            transceiver.sender.parameters = rtpParameters
         }
 
         val publication = LocalTrackPublication(
@@ -877,6 +899,14 @@ abstract class BaseVideoTrackPublishOptions {
      * will automatically publish a secondary track encoded with the backup codec.
      */
     abstract val backupCodec: BackupVideoCodec?
+
+    /**
+     * When bandwidth is constrained, this preference indicates which is preferred
+     * between degrading resolution vs. framerate.
+     *
+     * null value indicates default value (maintain framerate).
+     */
+    abstract val degradationPreference: RtpParameters.DegradationPreference?
 }
 
 data class VideoTrackPublishDefaults(
@@ -885,6 +915,7 @@ data class VideoTrackPublishDefaults(
     override val videoCodec: String = VideoCodec.VP8.codecName,
     override val scalabilityMode: String? = null,
     override val backupCodec: BackupVideoCodec? = null,
+    override val degradationPreference: RtpParameters.DegradationPreference? = null,
 ) : BaseVideoTrackPublishOptions()
 
 data class VideoTrackPublishOptions(
@@ -896,6 +927,7 @@ data class VideoTrackPublishOptions(
     override val backupCodec: BackupVideoCodec? = null,
     override val source: Track.Source? = null,
     override val stream: String? = null,
+    override val degradationPreference: RtpParameters.DegradationPreference? = null,
 ) : BaseVideoTrackPublishOptions(), TrackPublishOptions {
     constructor(
         name: String? = null,
@@ -911,6 +943,7 @@ data class VideoTrackPublishOptions(
         backupCodec = base.backupCodec,
         source = source,
         stream = stream,
+        degradationPreference = base.degradationPreference,
     )
 
     fun createBackupOptions(): VideoTrackPublishOptions? {

@@ -16,11 +16,30 @@
 
 package io.livekit.android.test.mock
 
+import livekit.org.webrtc.MockRtpParameters
+import livekit.org.webrtc.RtpParameters
 import livekit.org.webrtc.RtpSender
 import org.mockito.Mockito
+import org.mockito.kotlin.any
+import org.mockito.kotlin.whenever
+import java.util.UUID
 
 object MockRtpSender {
     fun create(): RtpSender {
-        return Mockito.mock(RtpSender::class.java)
+        var rtpParameters: RtpParameters = MockRtpParameters(
+            transactionId = UUID.randomUUID().toString(),
+            degradationPreference = null,
+            rtcp = MockRtpParameters.MockRtcp("", false),
+            headerExtensions = mutableListOf(),
+            encodings = mutableListOf(),
+            codecs = mutableListOf(),
+        )
+        return Mockito.mock(RtpSender::class.java).apply {
+            whenever(this.parameters).thenAnswer { rtpParameters }
+            whenever(this.setParameters(any())).thenAnswer {
+                rtpParameters = it.getArgument(0)
+                true
+            }
+        }
     }
 }

+/*
+ * Copyright 2024 LiveKit, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package livekit.org.webrtc
+
+class MockRtpParameters(
+    transactionId: String?,
+    degradationPreference: DegradationPreference?,
+    rtcp: Rtcp?,
+    headerExtensions: MutableList<HeaderExtension>?,
+    encodings: MutableList<Encoding>?,
+    codecs: MutableList<Codec>?,
+) : RtpParameters(transactionId, degradationPreference, rtcp, headerExtensions, encodings, codecs) {
+    class MockRtcp(cname: String?, reducedSize: Boolean) : Rtcp(cname, reducedSize)
+    class MockHeaderExtension(uri: String?, id: Int, encrypted: Boolean) : HeaderExtension(uri, id, encrypted)
+    class MockCodec(payloadType: Int, name: String?, kind: MediaStreamTrack.MediaType?, clockRate: Int?, numChannels: Int?, parameters: MutableMap<String, String>?) :
+        Codec(payloadType, name, kind, clockRate, numChannels, parameters)
+}

@@ -40,6 +40,7 @@ import livekit.LivekitModels
 import livekit.LivekitRtc
 import livekit.LivekitRtc.SubscribedCodec
 import livekit.LivekitRtc.SubscribedQuality
+import livekit.org.webrtc.RtpParameters
 import livekit.org.webrtc.VideoSource
 import org.junit.Assert.*
 import org.junit.Test
@@ -333,4 +334,18 @@ class LocalParticipantMockE2ETest : MockE2ETest() {
             },
         )
     }
+
+    @Test
+    fun publishDegradationPreferences() = runTest {
+        val preference = RtpParameters.DegradationPreference.DISABLED
+        room.videoTrackPublishDefaults = room.videoTrackPublishDefaults.copy(degradationPreference = preference)
+        connect()
+
+        room.localParticipant.publishVideoTrack(track = createLocalTrack())
+
+        val peerConnection = getPublisherPeerConnection()
+        val transceiver = peerConnection.transceivers.first()
+
+        assertEquals(preference, transceiver.sender.parameters.degradationPreference)
+    }
 }