Introduce RtpDataChannel interface.

#minor-release

PiperOrigin-RevId: 371326814

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/RtspMediaPeriod.java

@@ -43,11 +43,11 @@ import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.rtsp.RtspClient.PlaybackEventListener;
 import com.google.android.exoplayer2.source.rtsp.RtspMediaSource.RtspPlaybackException;
+import com.google.android.exoplayer2.source.rtsp.rtp.RtpDataChannel;
 import com.google.android.exoplayer2.source.rtsp.rtp.RtpDataLoadable;
 import com.google.android.exoplayer2.trackselection.ExoTrackSelection;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.Loader;
 import com.google.android.exoplayer2.upstream.Loader.Loadable;
 import com.google.android.exoplayer2.util.Util;
@@ -72,6 +72,7 @@ public final class RtspMediaPeriod implements MediaPeriod {
 
   private final InternalListener internalListener;
   private final RtspClient rtspClient;
+  private final RtpDataChannel.Factory rtpDataChannelFactory;
   private final List<RtspLoaderWrapper> rtspLoaderWrappers;
   private final List<RtpLoadInfo> selectedLoadInfos;
 
@@ -93,9 +94,13 @@ public final class RtspMediaPeriod implements MediaPeriod {
    * @param allocator An {@link Allocator} from which to obtain media buffer allocations.
    * @param rtspTracks A list of tracks in an RTSP playback session.
    * @param rtspClient The {@link RtspClient} for the current RTSP playback.
+   * @param rtpDataChannelFactory A {@link RtpDataChannel.Factory} for {@link RtpDataChannel}.
    */
   public RtspMediaPeriod(
-      Allocator allocator, List<RtspMediaTrack> rtspTracks, RtspClient rtspClient) {
+      Allocator allocator,
+      List<RtspMediaTrack> rtspTracks,
+      RtspClient rtspClient,
+      RtpDataChannel.Factory rtpDataChannelFactory) {
     this.allocator = allocator;
     handler = Util.createHandlerForCurrentLooper();
 
@@ -103,6 +108,7 @@ public final class RtspMediaPeriod implements MediaPeriod {
     rtspLoaderWrappers = new ArrayList<>(rtspTracks.size());
     this.rtspClient = rtspClient;
     this.rtspClient.setPlaybackEventListener(internalListener);
+    this.rtpDataChannelFactory = rtpDataChannelFactory;
 
     for (int i = 0; i < rtspTracks.size(); i++) {
       RtspMediaTrack rtspMediaTrack = rtspTracks.get(i);
@@ -506,7 +512,7 @@ public final class RtspMediaPeriod implements MediaPeriod {
       playbackException = error;
     }
 
-    /** Handles the {@link Loadable} whose {@link DataSource} timed out. */
+    /** Handles the {@link Loadable} whose {@link RtpDataChannel} timed out. */
     private void handleSocketTimeout(RtpDataLoadable loadable) {
       // TODO(b/172331505) Allow for retry when loading is not ending.
       if (getBufferedPositionUs() == Long.MIN_VALUE) {
@@ -648,7 +654,8 @@ public final class RtspMediaPeriod implements MediaPeriod {
               trackId,
               mediaTrack,
               /* eventListener= */ transportEventListener,
-              /* output= */ internalListener);
+              /* output= */ internalListener,
+              rtpDataChannelFactory);
     }
 
     /**

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/RtspMediaSource.java

@@ -31,6 +31,7 @@ import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.MediaSourceFactory;
 import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.source.rtsp.RtspClient.SessionInfoListener;
+import com.google.android.exoplayer2.source.rtsp.rtp.RtpDataChannel;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.upstream.LoadErrorHandlingPolicy;
@@ -131,6 +132,7 @@ public final class RtspMediaSource extends BaseMediaSource {
   }
 
   private final MediaItem mediaItem;
+  private final RtpDataChannel.Factory rtpDataChannelFactory;
   private @MonotonicNonNull RtspClient rtspClient;
 
   @Nullable private ImmutableList<RtspMediaTrack> rtspMediaTracks;
@@ -138,6 +140,7 @@ public final class RtspMediaSource extends BaseMediaSource {
 
   private RtspMediaSource(MediaItem mediaItem) {
     this.mediaItem = mediaItem;
+    rtpDataChannelFactory = RtpDataChannel.DEFAULT_FACTORY;
   }
 
   @Override
@@ -174,7 +177,8 @@ public final class RtspMediaSource extends BaseMediaSource {
 
   @Override
   public MediaPeriod createPeriod(MediaPeriodId id, Allocator allocator, long startPositionUs) {
-    return new RtspMediaPeriod(allocator, checkNotNull(rtspMediaTracks), checkNotNull(rtspClient));
+    return new RtspMediaPeriod(
+        allocator, checkNotNull(rtspMediaTracks), checkNotNull(rtspClient), rtpDataChannelFactory);
   }
 
   @Override

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/rtp/RtpDataChannel.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * 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 com.google.android.exoplayer2.source.rtsp.rtp;
+
+import com.google.android.exoplayer2.upstream.DataSource;
+
+/** An RTP {@link DataSource}. */
+public interface RtpDataChannel extends DataSource {
+
+  /** Creates {@link RtpDataChannel} for RTSP streams. */
+  interface Factory {
+
+    /** Creates a new {@link RtpDataChannel} instance. */
+    RtpDataChannel createDataChannel();
+  }
+
+  /** The default {@link Factory} that returns a new {@link UdpDataSourceRtpDataChannel}. */
+  Factory DEFAULT_FACTORY = UdpDataSourceRtpDataChannel::new;
+
+  /** Returns the local port used in the underlying transport channel. */
+  int getLocalPort();
+}

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/rtp/RtpDataLoadable.java

@@ -30,7 +30,6 @@ import com.google.android.exoplayer2.extractor.PositionHolder;
 import com.google.android.exoplayer2.source.rtsp.RtspMediaTrack;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.Loader;
-import com.google.android.exoplayer2.upstream.UdpDataSource;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@@ -39,10 +38,10 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  * A {@link Loader.Loadable} that sets up a sockets listening to incoming RTP traffic, carried by
  * UDP packets.
  *
- * <p>Uses a {@link UdpDataSource} to listen on incoming packets. The local UDP port is selected by
+ * <p>Uses a {@link RtpDataChannel} to listen on incoming packets. The local UDP port is selected by
- * the runtime on opening; it also opens another {@link UdpDataSource} for RTCP on the RTP UDP port
+ * the runtime on opening; it also opens another {@link RtpDataChannel} for RTCP on the RTP UDP port
  * number plus one one. Pass a listener via constructor to receive a callback when the local port is
- * opened. {@link #load} will throw an {@link IOException} if either of the two data sources fails
+ * opened. {@link #load} will throw an {@link IOException} if either of the two data channels fails
  * to open.
  *
  * <p>Received RTP packets' payloads will be extracted by an {@link RtpExtractor}, and will be
@@ -76,6 +75,7 @@ public final class RtpDataLoadable implements Loader.Loadable {
   private final EventListener eventListener;
   private final ExtractorOutput output;
   private final Handler playbackThreadHandler;
+  private final RtpDataChannel.Factory rtpDataChannelFactory;
 
   private @MonotonicNonNull RtpExtractor extractor;
 
@@ -92,17 +92,20 @@ public final class RtpDataLoadable implements Loader.Loadable {
    * @param rtspMediaTrack The {@link RtspMediaTrack} to load.
    * @param eventListener The {@link EventListener}.
    * @param output A {@link ExtractorOutput} instance to which the received and extracted data will
+   * @param rtpDataChannelFactory A {@link RtpDataChannel.Factory} for {@link RtpDataChannel}.
    */
   public RtpDataLoadable(
       int trackId,
       RtspMediaTrack rtspMediaTrack,
       EventListener eventListener,
-      ExtractorOutput output) {
+      ExtractorOutput output,
+      RtpDataChannel.Factory rtpDataChannelFactory) {
     this.trackId = trackId;
     this.rtspMediaTrack = rtspMediaTrack;
     this.eventListener = eventListener;
     this.output = output;
     this.playbackThreadHandler = Util.createHandlerForCurrentLooper();
+    this.rtpDataChannelFactory = rtpDataChannelFactory;
     pendingSeekPositionUs = C.TIME_UNSET;
   }
 
@@ -139,30 +142,30 @@ public final class RtpDataLoadable implements Loader.Loadable {
 
   @Override
   public void load() throws IOException {
-    @Nullable UdpDataSource firstDataSource = null;
+    @Nullable RtpDataChannel firstDataChannel = null;
-    @Nullable UdpDataSource secondDataSource = null;
+    @Nullable RtpDataChannel secondDataChannel = null;
 
     try {
-      // Open and set up the data sources.
+      // Open and set up the data channel.
       // From RFC3550 Section 11: "For UDP and similar protocols, RTP SHOULD use an even destination
       // port number and the corresponding RTCP stream SHOULD use the next higher (odd) destination
-      // port number". Some RTSP servers are strict about this rule.
+      // port number". Some RTSP servers are strict about this rule. We open a data channel first,
-      // We open a data source first, and depending its port number, open the next data source with
+      // and depending its port number, open the next data channel with a port number that is either
-      // a port number that is either the higher or the lower.
+      // the higher or the lower.
-      firstDataSource = new UdpDataSource();
+      firstDataChannel = rtpDataChannelFactory.createDataChannel();
-      firstDataSource.open(new DataSpec(Uri.parse(RTP_BIND_ADDRESS)));
+      firstDataChannel.open(new DataSpec(Uri.parse(RTP_BIND_ADDRESS)));
 
-      int firstPort = firstDataSource.getLocalPort();
+      int firstPort = firstDataChannel.getLocalPort();
       boolean isFirstPortNumberEven = (firstPort % 2 == 0);
       int secondPort = isFirstPortNumberEven ? firstPort + 1 : firstPort - 1;
 
       // RTCP always uses the immediate next port.
-      secondDataSource = new UdpDataSource();
+      secondDataChannel = rtpDataChannelFactory.createDataChannel();
-      secondDataSource.open(new DataSpec(Uri.parse(RTP_ANY_INCOMING_IPV4 + ":" + secondPort)));
+      secondDataChannel.open(new DataSpec(Uri.parse(RTP_ANY_INCOMING_IPV4 + ":" + secondPort)));
 
       // RTP data port is always the lower and even-numbered port.
-      UdpDataSource dataSource = isFirstPortNumberEven ? firstDataSource : secondDataSource;
+      RtpDataChannel dataChannel = isFirstPortNumberEven ? firstDataChannel : secondDataChannel;
-      int dataPort = dataSource.getLocalPort();
+      int dataPort = dataChannel.getLocalPort();
       int rtcpPort = dataPort + 1;
       String transport = Util.formatInvariant(DEFAULT_TRANSPORT_FORMAT, dataPort, rtcpPort);
       playbackThreadHandler.post(() -> eventListener.onTransportReady(transport));
@@ -170,7 +173,7 @@ public final class RtpDataLoadable implements Loader.Loadable {
       // Sets up the extractor.
       ExtractorInput extractorInput =
           new DefaultExtractorInput(
-              checkNotNull(dataSource), /* position= */ 0, /* length= */ C.LENGTH_UNSET);
+              checkNotNull(dataChannel), /* position= */ 0, /* length= */ C.LENGTH_UNSET);
       extractor = new RtpExtractor(rtspMediaTrack.payloadFormat, trackId);
       extractor.init(output);
 
@@ -183,8 +186,8 @@ public final class RtpDataLoadable implements Loader.Loadable {
         extractor.read(extractorInput, /* seekPosition= */ new PositionHolder());
       }
     } finally {
-      closeQuietly(firstDataSource);
+      closeQuietly(firstDataChannel);
-      closeQuietly(secondDataSource);
+      closeQuietly(secondDataChannel);
     }
   }
 

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/rtp/UdpDataSourceRtpDataChannel.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * 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 com.google.android.exoplayer2.source.rtsp.rtp;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.upstream.TransferListener;
+import com.google.android.exoplayer2.upstream.UdpDataSource;
+import java.io.IOException;
+
+/** An {@link RtpDataChannel} for UDP transport. */
+public final class UdpDataSourceRtpDataChannel implements RtpDataChannel {
+  private final UdpDataSource dataSource;
+
+  /** Creates a new instance. */
+  public UdpDataSourceRtpDataChannel() {
+    dataSource = new UdpDataSource();
+  }
+
+  @Override
+  public int getLocalPort() {
+    return dataSource.getLocalPort();
+  }
+
+  @Override
+  public void addTransferListener(TransferListener transferListener) {
+    dataSource.addTransferListener(transferListener);
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    return dataSource.open(dataSpec);
+  }
+
+  @Nullable
+  @Override
+  public Uri getUri() {
+    return dataSource.getUri();
+  }
+
+  @Override
+  public void close() {
+    dataSource.close();
+  }
+
+  @Override
+  public int read(byte[] target, int offset, int length) throws IOException {
+    return dataSource.read(target, offset, length);
+  }
+}

library/rtsp/src/test/java/com/google/android/exoplayer2/source/rtsp/RtspMediaPeriodTest.java

@@ -23,6 +23,7 @@ import androidx.annotation.Nullable;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.MediaPeriod;
+import com.google.android.exoplayer2.source.rtsp.rtp.RtpDataChannel;
 import com.google.android.exoplayer2.source.rtsp.sdp.MediaDescription;
 import com.google.android.exoplayer2.source.rtsp.sdp.SessionDescription;
 import com.google.android.exoplayer2.upstream.DefaultAllocator;
@@ -68,7 +69,8 @@ public class RtspMediaPeriodTest {
                         .addAttribute(SessionDescription.ATTR_CONTROL, "track1")
                         .build(),
                     Uri.parse("rtsp://localhost/test"))),
-            PLACEHOLDER_RTSP_CLIENT);
+            PLACEHOLDER_RTSP_CLIENT,
+            RtpDataChannel.DEFAULT_FACTORY);
 
     AtomicBoolean prepareCallbackCalled = new AtomicBoolean(false);
     rtspMediaPeriod.prepare(
@@ -95,7 +97,8 @@ public class RtspMediaPeriodTest {
         new RtspMediaPeriod(
             new DefaultAllocator(/* trimOnReset= */ true, C.DEFAULT_BUFFER_SEGMENT_SIZE),
             ImmutableList.of(),
-            PLACEHOLDER_RTSP_CLIENT);
+            PLACEHOLDER_RTSP_CLIENT,
+            RtpDataChannel.DEFAULT_FACTORY);
 
     assertThat(rtspMediaPeriod.getBufferedPositionUs()).isEqualTo(C.TIME_END_OF_SOURCE);
   }