Add factory method to for using TCP streaming.

#minor-release

PiperOrigin-RevId: 377476603

RELEASENOTES.md

@@ -93,6 +93,7 @@
 *   GL demo app:
     *   Fix texture transformation to avoid green bars shown on some videos
         ([#8992](https://github.com/google/ExoPlayer/issues/8992)).
+    *   Add `RtspMediaSource.Factory` option to force using TCP for streaming.
 
 ### 2.14.0 (2021-05-13)
 

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

@@ -84,7 +84,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private boolean prepared;
   private boolean trackSelected;
   private int portBindingRetryCount;
-  private boolean hasRetriedWithRtpTcp;
+  private boolean isUsingRtpTcp;
 
   /**
    * Creates an RTSP media period.
@@ -514,12 +514,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     private LoadErrorAction handleSocketTimeout(RtpDataLoadable loadable) {
       // TODO(b/172331505) Allow for retry when loading is not ending.
       if (getBufferedPositionUs() == Long.MIN_VALUE) {
-        // Retry playback with TCP if no sample has been received so far.
-        if (!hasRetriedWithRtpTcp) {
+        if (!isUsingRtpTcp) {
+          // Retry playback with TCP if no sample has been received so far, and we are not already
+          // using TCP. Retrying will setup new loadables, so will not retry with the current
+          // loadables.
           retryWithRtpTcp();
-          hasRetriedWithRtpTcp = true;
+          isUsingRtpTcp = true;
         }
-        // Don't retry with the current UDP backed loadables.
         return Loader.DONT_RETRY;
       }
 
@@ -685,6 +686,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
         RtspMediaTrack mediaTrack, int trackId, RtpDataChannel.Factory rtpDataChannelFactory) {
       this.mediaTrack = mediaTrack;
 
+      // This listener runs on the playback thread, posted by the Loader thread.
       RtpDataLoadable.EventListener transportEventListener =
           (transport, rtpDataChannel) -> {
             RtpLoadInfo.this.transport = transport;
@@ -695,8 +697,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
             if (interleavedBinaryDataListener != null) {
               rtspClient.registerInterleavedDataChannel(
                   rtpDataChannel.getLocalPort(), interleavedBinaryDataListener);
+              isUsingRtpTcp = true;
             }
-
             maybeSetupTracks();
           };
 

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

@@ -63,6 +63,24 @@ public final class RtspMediaSource extends BaseMediaSource {
    */
   public static final class Factory implements MediaSourceFactory {
 
+    private boolean forceUseRtpTcp;
+
+    /**
+     * Sets whether to force using TCP as the default RTP transport.
+     *
+     * <p>The default value is {@code false}, the source will first try streaming RTSP with UDP. If
+     * no data is received on the UDP channel (for instance, when streaming behind a NAT) for a
+     * while, the source will switch to streaming using TCP. If this value is set to {@code true},
+     * the source will always use TCP for streaming.
+     *
+     * @param forceUseRtpTcp Whether force to use TCP for streaming.
+     * @return This Factory, for convenience.
+     */
+    public Factory setForceUseRtpTcp(boolean forceUseRtpTcp) {
+      this.forceUseRtpTcp = forceUseRtpTcp;
+      return this;
+    }
+
     /** Does nothing. {@link RtspMediaSource} does not support DRM. */
     @Override
     public Factory setDrmSessionManagerProvider(
@@ -127,7 +145,11 @@ public final class RtspMediaSource extends BaseMediaSource {
     @Override
     public RtspMediaSource createMediaSource(MediaItem mediaItem) {
       checkNotNull(mediaItem.playbackProperties);
-      return new RtspMediaSource(mediaItem);
+      return new RtspMediaSource(
+          mediaItem,
+          forceUseRtpTcp
+              ? new TransferRtpDataChannelFactory()
+              : new UdpDataSourceRtpDataChannelFactory());
     }
   }
 
@@ -153,9 +175,9 @@ public final class RtspMediaSource extends BaseMediaSource {
   @Nullable private ImmutableList<RtspMediaTrack> rtspMediaTracks;
   @Nullable private IOException sourcePrepareException;
 
-  private RtspMediaSource(MediaItem mediaItem) {
+  private RtspMediaSource(MediaItem mediaItem, RtpDataChannel.Factory rtpDataChannelFactory) {
     this.mediaItem = mediaItem;
-    rtpDataChannelFactory = new UdpDataSourceRtpDataChannelFactory();
+    this.rtpDataChannelFactory = rtpDataChannelFactory;
   }
 
   @Override