Handle seek after playback ends

Reusing the loader wrappers allows us to use the current RTSP connection
without having to set up a new RTSP connection. Consequently, the Extractors,
RTP readers are also preserved.

PiperOrigin-RevId: 524663012

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtpDataChannel.java

@@ -53,6 +53,9 @@ import java.io.IOException;
    */
   int getLocalPort();
 
+  /** Returns whether the {@code RtpDataChannel} needs to be closed when loading completes. */
+  boolean needsClosingOnLoadCompletion();
+
   /**
    * Returns a {@link InterleavedBinaryDataListener} if the implementation supports receiving RTP
    * packets on a side-band protocol, for example RTP-over-RTSP; otherwise {@code null}.

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtpDataLoadable.java

@@ -27,7 +27,6 @@ import androidx.media3.datasource.DataSourceUtil;
 import androidx.media3.exoplayer.upstream.Loader;
 import androidx.media3.extractor.DefaultExtractorInput;
 import androidx.media3.extractor.Extractor;
-import androidx.media3.extractor.ExtractorInput;
 import androidx.media3.extractor.ExtractorOutput;
 import androidx.media3.extractor.PositionHolder;
 import java.io.IOException;
@@ -77,7 +76,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private final Handler playbackThreadHandler;
   private final RtpDataChannel.Factory rtpDataChannelFactory;
 
+  @Nullable private RtpDataChannel dataChannel;
   private @MonotonicNonNull RtpExtractor extractor;
+  private @MonotonicNonNull DefaultExtractorInput extractorInput;
 
   private volatile boolean loadCancelled;
   private volatile long pendingSeekPositionUs;
@@ -142,36 +143,49 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
   @Override
   public void load() throws IOException {
-    @Nullable RtpDataChannel dataChannel = null;
-    try {
-      dataChannel = rtpDataChannelFactory.createAndOpenDataChannel(trackId);
-      String transport = dataChannel.getTransport();
-
-      RtpDataChannel finalDataChannel = dataChannel;
-      playbackThreadHandler.post(() -> eventListener.onTransportReady(transport, finalDataChannel));
+    // Allows to resume loading after canceling load.
+    if (loadCancelled) {
+      loadCancelled = false;
+    }
 
-      // Sets up the extractor.
-      ExtractorInput extractorInput =
-          new DefaultExtractorInput(
-              checkNotNull(dataChannel), /* position= */ 0, /* length= */ C.LENGTH_UNSET);
-      extractor = new RtpExtractor(rtspMediaTrack.payloadFormat, trackId);
-      extractor.init(output);
+    try {
+      if (dataChannel == null) {
+        dataChannel = rtpDataChannelFactory.createAndOpenDataChannel(trackId);
+        String transport = dataChannel.getTransport();
+
+        RtpDataChannel finalDataChannel = dataChannel;
+        playbackThreadHandler.post(
+            () -> eventListener.onTransportReady(transport, finalDataChannel));
+
+        extractorInput =
+            new DefaultExtractorInput(
+                checkNotNull(dataChannel), /* position= */ 0, /* length= */ C.LENGTH_UNSET);
+        extractor = new RtpExtractor(rtspMediaTrack.payloadFormat, trackId);
+        extractor.init(output);
+      }
 
       while (!loadCancelled) {
         if (pendingSeekPositionUs != C.TIME_UNSET) {
-          extractor.seek(nextRtpTimestamp, pendingSeekPositionUs);
+          checkNotNull(extractor).seek(nextRtpTimestamp, pendingSeekPositionUs);
           pendingSeekPositionUs = C.TIME_UNSET;
         }
 
         @Extractor.ReadResult
-        int readResult = extractor.read(extractorInput, /* seekPosition= */ new PositionHolder());
+        int readResult =
+            checkNotNull(extractor)
+                .read(checkNotNull(extractorInput), /* seekPosition= */ new PositionHolder());
         if (readResult == Extractor.RESULT_END_OF_INPUT) {
           // Loading is finished.
           break;
         }
       }
+      // Resets the flag if user cancels loading.
+      loadCancelled = false;
     } finally {
-      DataSourceUtil.closeQuietly(dataChannel);
+      if (checkNotNull(dataChannel).needsClosingOnLoadCompletion()) {
+        DataSourceUtil.closeQuietly(dataChannel);
+        dataChannel = null;
+      }
     }
   }
 

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtspClient.java

@@ -230,6 +230,10 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     messageSender.sendPlayRequest(uri, offsetMs, checkNotNull(sessionId));
   }
 
+  public void signalPlaybackEnded() {
+    rtspState = RTSP_STATE_READY;
+  }
+
   /**
    * Seeks to a specific time using RTSP.
    *
@@ -723,7 +727,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
 
     private void onPlayResponseReceived(RtspPlayResponse response) {
-      checkState(rtspState == RTSP_STATE_READY);
+      checkState(rtspState == RTSP_STATE_READY || rtspState == RTSP_STATE_PLAYING);
 
       rtspState = RTSP_STATE_PLAYING;
       if (keepAliveMonitor == null) {

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtspMediaPeriod.java

@@ -19,6 +19,7 @@ package androidx.media3.exoplayer.rtsp;
 import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.common.util.Assertions.checkStateNotNull;
+import static androidx.media3.common.util.Util.usToMs;
 import static java.lang.Math.min;
 
 import android.net.Uri;
@@ -314,7 +315,22 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
 
     pendingSeekPositionUs = positionUs;
-    rtspClient.seekToUs(positionUs);
+
+    if (loadingFinished) {
+      for (int i = 0; i < rtspLoaderWrappers.size(); i++) {
+        rtspLoaderWrappers.get(i).resumeLoad();
+      }
+
+      if (isUsingRtpTcp) {
+        rtspClient.startPlayback(/* offsetMs= */ usToMs(positionUs));
+      } else {
+        rtspClient.seekToUs(positionUs);
+      }
+
+    } else {
+      rtspClient.seekToUs(positionUs);
+    }
+
     for (int i = 0; i < rtspLoaderWrappers.size(); i++) {
       rtspLoaderWrappers.get(i).seekTo(positionUs);
     }
@@ -530,6 +546,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
           break;
         }
       }
+
+      rtspClient.signalPlaybackEnded();
     }
 
     @Override
@@ -817,6 +835,14 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       }
     }
 
+    /** Resumes loading after {@linkplain #cancelLoad() loading is canceled}. */
+    public void resumeLoad() {
+      checkState(canceled);
+      canceled = false;
+      updateLoadingFinished();
+      startLoading();
+    }
+
     /** Resets the {@link Loadable} and {@link SampleQueue} to prepare for an RTSP seek. */
     public void seekTo(long positionUs) {
       if (!canceled) {

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/TransferRtpDataChannel.java

@@ -70,6 +70,12 @@ import java.util.concurrent.LinkedBlockingQueue;
   }
 
   @Override
+  public boolean needsClosingOnLoadCompletion() {
+    // TCP channel is managed by the RTSP mesasge channel and does not need closing from here.
+    return false;
+  }
+
+  @Override
   public InterleavedBinaryDataListener getInterleavedBinaryDataListener() {
     return this;
   }

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/UdpDataSourceRtpDataChannel.java

@@ -64,6 +64,11 @@ import java.io.IOException;
     return port == UdpDataSource.UDP_PORT_UNSET ? C.INDEX_UNSET : port;
   }
 
+  @Override
+  public boolean needsClosingOnLoadCompletion() {
+    return true;
+  }
+
   @Nullable
   @Override
   public RtspMessageChannel.InterleavedBinaryDataListener getInterleavedBinaryDataListener() {

libraries/exoplayer_rtsp/src/test/java/androidx/media3/exoplayer/rtsp/RtspPlaybackTest.java

@@ -442,6 +442,11 @@ public final class RtspPlaybackTest {
     }
 
     @Override
+    public boolean needsClosingOnLoadCompletion() {
+      return false;
+    }
+
+    @Override
     public RtspMessageChannel.InterleavedBinaryDataListener getInterleavedBinaryDataListener() {
       return null;
     }
@@ -454,6 +459,11 @@ public final class RtspPlaybackTest {
       return Util.formatInvariant(
           "RTP/AVP/TCP;unicast;interleaved=%d-%d", LOCAL_PORT + 2, LOCAL_PORT + 3);
     }
+
+    @Override
+    public boolean needsClosingOnLoadCompletion() {
+      return false;
+    }
   }
 
   private static class ForwardingRtpDataChannelFactory implements RtpDataChannel.Factory {