Correctly handle a SampleStream ending without providing a format

I'm going to introduce an EmptySampleStream that will be used in
some cases in conjunction as part of 608/EMSG support. This change
avoids EmptySampleStream having to provide a dummy format.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148383831

extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java

@@ -65,6 +65,7 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
   private final boolean playClearSamplesWithoutKeys;
   private final EventDispatcher eventDispatcher;
   private final FormatHolder formatHolder;
+  private final DecoderInputBuffer flagsOnlyBuffer;
   private final DrmSessionManager<ExoMediaCrypto> drmSessionManager;
 
   private DecoderCounters decoderCounters;
@@ -149,6 +150,7 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
     joiningDeadlineMs = -1;
     clearLastReportedVideoSize();
     formatHolder = new FormatHolder();
+    flagsOnlyBuffer = new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_DISABLED);
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
     outputMode = VpxDecoder.OUTPUT_MODE_NONE;
   }
@@ -165,10 +167,22 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
       return;
     }
 
-    // Try and read a format if we don't have one already.
+    if (format == null) {
-    if (format == null && !readFormat()) {
+      // We don't have a format yet, so try and read one.
-      // We can't make progress without one.
+      flagsOnlyBuffer.clear();
-      return;
+      int result = readSource(formatHolder, flagsOnlyBuffer, true);
+      if (result == C.RESULT_FORMAT_READ) {
+        onInputFormatChanged(formatHolder.format);
+      } else if (result == C.RESULT_BUFFER_READ) {
+        // End of stream read having not read a format.
+        Assertions.checkState(flagsOnlyBuffer.isEndOfStream());
+        inputStreamEnded = true;
+        outputStreamEnded = true;
+        return;
+      } else {
+        // We still don't have a format and can't make progress without one.
+        return;
+      }
     }
 
     if (isRendererAvailable()) {
@@ -327,7 +341,7 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
       // We've already read an encrypted sample into buffer, and are waiting for keys.
       result = C.RESULT_BUFFER_READ;
     } else {
-      result = readSource(formatHolder, inputBuffer);
+      result = readSource(formatHolder, inputBuffer, false);
     }
 
     if (result == C.RESULT_NOTHING_READ) {
@@ -485,15 +499,6 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
     }
   }
 
-  private boolean readFormat() throws ExoPlaybackException {
-    int result = readSource(formatHolder, null);
-    if (result == C.RESULT_FORMAT_READ) {
-      onInputFormatChanged(formatHolder.format);
-      return true;
-    }
-    return false;
-  }
-
   private void onInputFormatChanged(Format newFormat) throws ExoPlaybackException {
     Format oldFormat = format;
     format = newFormat;

library/src/androidTest/java/com/google/android/exoplayer2/ExoPlayerTest.java

@@ -513,8 +513,9 @@ public final class ExoPlayerTest extends TestCase {
     }
 
     @Override
-    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
-      if (buffer == null || !readFormat) {
+        boolean formatRequired) {
+      if (formatRequired || !readFormat) {
         formatHolder.format = format;
         readFormat = true;
         return C.RESULT_FORMAT_READ;
@@ -571,7 +572,7 @@ public final class ExoPlayerTest extends TestCase {
       FormatHolder formatHolder = new FormatHolder();
       DecoderInputBuffer buffer =
           new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_NORMAL);
-      int result = readSource(formatHolder, buffer);
+      int result = readSource(formatHolder, buffer, false);
       if (result == C.RESULT_FORMAT_READ) {
         formatReadCount++;
         assertEquals(expectedFormat, formatHolder.format);

library/src/main/java/com/google/android/exoplayer2/BaseRenderer.java

@@ -262,13 +262,16 @@ public abstract class BaseRenderer implements Renderer, RendererCapabilities {
    * @param formatHolder A {@link FormatHolder} to populate in the case of reading a format.
    * @param buffer A {@link DecoderInputBuffer} to populate in the case of reading a sample or the
    *     end of the stream. If the end of the stream has been reached, the
-   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer. May be null if the
+   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer.
-   *     caller requires that the format of the stream be read even if it's not changing.
+   * @param formatRequired Whether the caller requires that the format of the stream be read even if
+   *     it's not changing. A sample will never be read if set to true, however it is still possible
+   *     for the end of stream or nothing to be read.
    * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ} or
    *     {@link C#RESULT_BUFFER_READ}.
    */
-  protected final int readSource(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+  protected final int readSource(FormatHolder formatHolder, DecoderInputBuffer buffer,
-    int result = stream.readData(formatHolder, buffer);
+      boolean formatRequired) {
+    int result = stream.readData(formatHolder, buffer, formatRequired);
     if (result == C.RESULT_BUFFER_READ) {
       if (buffer.isEndOfStream()) {
         readEndOfStream = true;

library/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java

@@ -34,6 +34,7 @@ import com.google.android.exoplayer2.decoder.SimpleOutputBuffer;
 import com.google.android.exoplayer2.drm.DrmSession;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
 import com.google.android.exoplayer2.drm.ExoMediaCrypto;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MediaClock;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.TraceUtil;
@@ -67,12 +68,12 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
    */
   private static final int REINITIALIZATION_STATE_WAIT_END_OF_STREAM = 2;
 
+  private final DrmSessionManager<ExoMediaCrypto> drmSessionManager;
   private final boolean playClearSamplesWithoutKeys;
-
   private final EventDispatcher eventDispatcher;
   private final AudioTrack audioTrack;
-  private final DrmSessionManager<ExoMediaCrypto> drmSessionManager;
   private final FormatHolder formatHolder;
+  private final DecoderInputBuffer flagsOnlyBuffer;
 
   private DecoderCounters decoderCounters;
   private Format inputFormat;
@@ -142,11 +143,12 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       DrmSessionManager<ExoMediaCrypto> drmSessionManager, boolean playClearSamplesWithoutKeys,
       BufferProcessor... bufferProcessors) {
     super(C.TRACK_TYPE_AUDIO);
+    this.drmSessionManager = drmSessionManager;
+    this.playClearSamplesWithoutKeys = playClearSamplesWithoutKeys;
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
     audioTrack = new AudioTrack(audioCapabilities, bufferProcessors, new AudioTrackListener());
-    this.drmSessionManager = drmSessionManager;
     formatHolder = new FormatHolder();
-    this.playClearSamplesWithoutKeys = playClearSamplesWithoutKeys;
+    flagsOnlyBuffer = new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_DISABLED);
     decoderReinitializationState = REINITIALIZATION_STATE_NONE;
     audioTrackNeedsConfigure = true;
   }
@@ -187,9 +189,22 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
     }
 
     // Try and read a format if we don't have one already.
-    if (inputFormat == null && !readFormat()) {
+    if (inputFormat == null) {
-      // We can't make progress without one.
+      // We don't have a format yet, so try and read one.
-      return;
+      flagsOnlyBuffer.clear();
+      int result = readSource(formatHolder, flagsOnlyBuffer, true);
+      if (result == C.RESULT_FORMAT_READ) {
+        onInputFormatChanged(formatHolder.format);
+      } else if (result == C.RESULT_BUFFER_READ) {
+        // End of stream read having not read a format.
+        Assertions.checkState(flagsOnlyBuffer.isEndOfStream());
+        inputStreamEnded = true;
+        processEndOfStream();
+        return;
+      } else {
+        // We still don't have a format and can't make progress without one.
+        return;
+      }
     }
 
     // If we don't have a decoder yet, we need to instantiate one.
@@ -284,8 +299,7 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       } else {
         outputBuffer.release();
         outputBuffer = null;
-        outputStreamEnded = true;
+        processEndOfStream();
-        audioTrack.playToEndOfStream();
       }
       return false;
     }
@@ -334,7 +348,7 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       // We've already read an encrypted sample into buffer, and are waiting for keys.
       result = C.RESULT_BUFFER_READ;
     } else {
-      result = readSource(formatHolder, inputBuffer);
+      result = readSource(formatHolder, inputBuffer, false);
     }
 
     if (result == C.RESULT_NOTHING_READ) {
@@ -375,6 +389,15 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
         && (bufferEncrypted || !playClearSamplesWithoutKeys);
   }
 
+  private void processEndOfStream() throws ExoPlaybackException {
+    outputStreamEnded = true;
+    try {
+      audioTrack.playToEndOfStream();
+    } catch (AudioTrack.WriteException e) {
+      throw ExoPlaybackException.createForRenderer(drmSession.getError(), getIndex());
+    }
+  }
+
   private void flushDecoder() throws ExoPlaybackException {
     waitingForKeys = false;
     if (decoderReinitializationState != REINITIALIZATION_STATE_NONE) {
@@ -523,15 +546,6 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
     decoderReceivedBuffers = false;
   }
 
-  private boolean readFormat() throws ExoPlaybackException {
-    int result = readSource(formatHolder, null);
-    if (result == C.RESULT_FORMAT_READ) {
-      onInputFormatChanged(formatHolder.format);
-      return true;
-    }
-    return false;
-  }
-
   private void onInputFormatChanged(Format newFormat) throws ExoPlaybackException {
     Format oldFormat = inputFormat;
     inputFormat = newFormat;

library/src/main/java/com/google/android/exoplayer2/extractor/DefaultTrackOutput.java

@@ -267,40 +267,42 @@ public final class DefaultTrackOutput implements TrackOutput {
    * @param formatHolder A {@link FormatHolder} to populate in the case of reading a format.
    * @param buffer A {@link DecoderInputBuffer} to populate in the case of reading a sample or the
    *     end of the stream. If the end of the stream has been reached, the
-   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer.  May be null if the
+   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer.
-   *     caller requires that the format of the stream be read even if it's not changing.
+   * @param formatRequired Whether the caller requires that the format of the stream be read even if
+   *     it's not changing. A sample will never be read if set to true, however it is still possible
+   *     for the end of stream or nothing to be read.
    * @param loadingFinished True if an empty queue should be considered the end of the stream.
    * @param decodeOnlyUntilUs If a buffer is read, the {@link C#BUFFER_FLAG_DECODE_ONLY} flag will
    *     be set if the buffer's timestamp is less than this value.
    * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ} or
    *     {@link C#RESULT_BUFFER_READ}.
    */
-  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean loadingFinished,
+  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired,
-      long decodeOnlyUntilUs) {
+      boolean loadingFinished, long decodeOnlyUntilUs) {
-    switch (infoQueue.readData(formatHolder, buffer, downstreamFormat, extrasHolder)) {
+    int result = infoQueue.readData(formatHolder, buffer, formatRequired, loadingFinished,
-      case C.RESULT_NOTHING_READ:
+        downstreamFormat, extrasHolder);
-        if (loadingFinished) {
+    switch (result) {
-          buffer.setFlags(C.BUFFER_FLAG_END_OF_STREAM);
-          return C.RESULT_BUFFER_READ;
-        }
-        return C.RESULT_NOTHING_READ;
       case C.RESULT_FORMAT_READ:
         downstreamFormat = formatHolder.format;
         return C.RESULT_FORMAT_READ;
       case C.RESULT_BUFFER_READ:
-        if (buffer.timeUs < decodeOnlyUntilUs) {
+        if (!buffer.isEndOfStream()) {
-          buffer.addFlag(C.BUFFER_FLAG_DECODE_ONLY);
+          if (buffer.timeUs < decodeOnlyUntilUs) {
+            buffer.addFlag(C.BUFFER_FLAG_DECODE_ONLY);
+          }
+          // Read encryption data if the sample is encrypted.
+          if (buffer.isEncrypted()) {
+            readEncryptionData(buffer, extrasHolder);
+          }
+          // Write the sample data into the holder.
+          buffer.ensureSpaceForWrite(extrasHolder.size);
+          readData(extrasHolder.offset, buffer.data, extrasHolder.size);
+          // Advance the read head.
+          dropDownstreamTo(extrasHolder.nextOffset);
         }
-        // Read encryption data if the sample is encrypted.
-        if (buffer.isEncrypted()) {
-          readEncryptionData(buffer, extrasHolder);
-        }
-        // Write the sample data into the holder.
-        buffer.ensureSpaceForWrite(extrasHolder.size);
-        readData(extrasHolder.offset, buffer.data, extrasHolder.size);
-        // Advance the read head.
-        dropDownstreamTo(extrasHolder.nextOffset);
         return C.RESULT_BUFFER_READ;
+      case C.RESULT_NOTHING_READ:
+        return C.RESULT_NOTHING_READ;
       default:
         throw new IllegalStateException();
     }
@@ -760,23 +762,34 @@ public final class DefaultTrackOutput implements TrackOutput {
      *     and the absolute position of the first byte that may still be required after the current
      *     sample has been read. May be null if the caller requires that the format of the stream be
      *     read even if it's not changing.
+     * @param formatRequired Whether the caller requires that the format of the stream be read even
+     *     if it's not changing. A sample will never be read if set to true, however it is still
+     *     possible for the end of stream or nothing to be read.
+     * @param loadingFinished True if an empty queue should be considered the end of the stream.
      * @param downstreamFormat The current downstream {@link Format}. If the format of the next
      *     sample is different to the current downstream format then a format will be read.
      * @param extrasHolder The holder into which extra sample information should be written.
      * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ}
      *     or {@link C#RESULT_BUFFER_READ}.
      */
+    @SuppressWarnings("ReferenceEquality")
     public synchronized int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
-        Format downstreamFormat, BufferExtrasHolder extrasHolder) {
+        boolean formatRequired, boolean loadingFinished, Format downstreamFormat,
+        BufferExtrasHolder extrasHolder) {
       if (queueSize == 0) {
-        if (upstreamFormat != null && (buffer == null || upstreamFormat != downstreamFormat)) {
+        if (loadingFinished) {
+          buffer.setFlags(C.BUFFER_FLAG_END_OF_STREAM);
+          return C.RESULT_BUFFER_READ;
+        } else if (upstreamFormat != null
+            && (formatRequired || upstreamFormat != downstreamFormat)) {
           formatHolder.format = upstreamFormat;
           return C.RESULT_FORMAT_READ;
+        } else {
+          return C.RESULT_NOTHING_READ;
         }
-        return C.RESULT_NOTHING_READ;
       }
 
-      if (buffer == null || formats[relativeReadIndex] != downstreamFormat) {
+      if (formatRequired || formats[relativeReadIndex] != downstreamFormat) {
         formatHolder.format = formats[relativeReadIndex];
         return C.RESULT_FORMAT_READ;
       }

library/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecRenderer.java

@@ -484,7 +484,21 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
       return;
     }
     if (format == null) {
-      readFormat();
+      // We don't have a format yet, so try and read one.
+      buffer.clear();
+      int result = readSource(formatHolder, buffer, true);
+      if (result == C.RESULT_FORMAT_READ) {
+        onInputFormatChanged(formatHolder.format);
+      } else if (result == C.RESULT_BUFFER_READ) {
+        // End of stream read having not read a format.
+        Assertions.checkState(buffer.isEndOfStream());
+        inputStreamEnded = true;
+        processEndOfStream();
+        return;
+      } else {
+        // We still don't have a format and can't make progress without one.
+        return;
+      }
     }
     maybeInitCodec();
     if (codec != null) {
@@ -498,13 +512,6 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
     decoderCounters.ensureUpdated();
   }
 
-  private void readFormat() throws ExoPlaybackException {
-    int result = readSource(formatHolder, null);
-    if (result == C.RESULT_FORMAT_READ) {
-      onInputFormatChanged(formatHolder.format);
-    }
-  }
-
   protected void flushCodec() throws ExoPlaybackException {
     codecHotswapDeadlineMs = C.TIME_UNSET;
     inputIndex = C.INDEX_UNSET;
@@ -594,7 +601,7 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
         codecReconfigurationState = RECONFIGURATION_STATE_QUEUE_PENDING;
       }
       adaptiveReconfigurationBytes = buffer.data.position();
-      result = readSource(formatHolder, buffer);
+      result = readSource(formatHolder, buffer, false);
     }
 
     if (result == C.RESULT_NOTHING_READ) {

library/src/main/java/com/google/android/exoplayer2/metadata/MetadataRenderer.java

@@ -109,7 +109,7 @@ public final class MetadataRenderer extends BaseRenderer implements Callback {
   public void render(long positionUs, long elapsedRealtimeUs) throws ExoPlaybackException {
     if (!inputStreamEnded && pendingMetadata == null) {
       buffer.clear();
-      int result = readSource(formatHolder, buffer);
+      int result = readSource(formatHolder, buffer, false);
       if (result == C.RESULT_BUFFER_READ) {
         if (buffer.isEndOfStream()) {
           inputStreamEnded = true;

library/src/main/java/com/google/android/exoplayer2/source/ClippingMediaPeriod.java

@@ -231,18 +231,16 @@ public final class ClippingMediaPeriod implements MediaPeriod, MediaPeriod.Callb
     }
 
     @Override
-    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
+        boolean requireFormat) {
       if (pendingDiscontinuity) {
         return C.RESULT_NOTHING_READ;
       }
-      if (buffer == null) {
-        return stream.readData(formatHolder, null);
-      }
       if (sentEos) {
         buffer.setFlags(C.BUFFER_FLAG_END_OF_STREAM);
         return C.RESULT_BUFFER_READ;
       }
-      int result = stream.readData(formatHolder, buffer);
+      int result = stream.readData(formatHolder, buffer, requireFormat);
       // TODO: Clear gapless playback metadata if a format was read (if applicable).
       if (endUs != C.TIME_END_OF_SOURCE && ((result == C.RESULT_BUFFER_READ
           && buffer.timeUs >= endUs) || (result == C.RESULT_NOTHING_READ

library/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaPeriod.java

@@ -325,13 +325,14 @@ import java.io.IOException;
     loader.maybeThrowError();
   }
 
-  /* package */ int readData(int track, FormatHolder formatHolder, DecoderInputBuffer buffer) {
+  /* package */ int readData(int track, FormatHolder formatHolder, DecoderInputBuffer buffer,
+      boolean formatRequired) {
     if (notifyReset || isPendingReset()) {
       return C.RESULT_NOTHING_READ;
     }
 
-    return sampleQueues.valueAt(track).readData(formatHolder, buffer, loadingFinished,
+    return sampleQueues.valueAt(track).readData(formatHolder, buffer, formatRequired,
-        lastSeekPositionUs);
+        loadingFinished, lastSeekPositionUs);
   }
 
   // Loader.Callback implementation.
@@ -552,8 +553,9 @@ import java.io.IOException;
     }
 
     @Override
-    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
-      return ExtractorMediaPeriod.this.readData(track, formatHolder, buffer);
+        boolean formatRequired) {
+      return ExtractorMediaPeriod.this.readData(track, formatHolder, buffer, formatRequired);
     }
 
     @Override

library/src/main/java/com/google/android/exoplayer2/source/SampleStream.java

@@ -45,20 +45,24 @@ public interface SampleStream {
   /**
    * Attempts to read from the stream.
    * <p>
-   * If no data is available then {@link C#RESULT_NOTHING_READ} is returned. If the format of the
+   * If the stream has ended then {@link C#BUFFER_FLAG_END_OF_STREAM} flag is set on {@code buffer}
-   * media is changing or if {@code buffer == null} then {@code formatHolder} is populated and
+   * and {@link C#RESULT_BUFFER_READ} is returned. Else if no data is available then
+   * {@link C#RESULT_NOTHING_READ} is returned. Else if the format of the media is changing or if
+   * {@code formatRequired} is set then {@code formatHolder} is populated and
    * {@link C#RESULT_FORMAT_READ} is returned. Else {@code buffer} is populated and
    * {@link C#RESULT_BUFFER_READ} is returned.
    *
    * @param formatHolder A {@link FormatHolder} to populate in the case of reading a format.
    * @param buffer A {@link DecoderInputBuffer} to populate in the case of reading a sample or the
    *     end of the stream. If the end of the stream has been reached, the
-   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer. May be null if the
+   *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer.
-   *     caller requires that the format of the stream be read even if it's not changing.
+   * @param formatRequired Whether the caller requires that the format of the stream be read even if
+   *     it's not changing. A sample will never be read if set to true, however it is still possible
+   *     for the end of stream or nothing to be read.
    * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ} or
    *     {@link C#RESULT_BUFFER_READ}.
    */
-  int readData(FormatHolder formatHolder, DecoderInputBuffer buffer);
+  int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired);
 
   /**
    * Attempts to skip to the keyframe before the specified time.

library/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaPeriod.java

@@ -205,14 +205,15 @@ import java.util.Arrays;
     }
 
     @Override
-    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
-      if (buffer == null || streamState == STREAM_STATE_SEND_FORMAT) {
+        boolean requireFormat) {
+      if (streamState == STREAM_STATE_END_OF_STREAM) {
+        buffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
+        return C.RESULT_BUFFER_READ;
+      } else if (requireFormat || streamState == STREAM_STATE_SEND_FORMAT) {
         formatHolder.format = format;
         streamState = STREAM_STATE_SEND_SAMPLE;
         return C.RESULT_FORMAT_READ;
-      } else if (streamState == STREAM_STATE_END_OF_STREAM) {
-        buffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
-        return C.RESULT_BUFFER_READ;
       }
 
       Assertions.checkState(streamState == STREAM_STATE_SEND_SAMPLE);

library/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java

@@ -169,7 +169,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   }
 
   @Override
-  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
+      boolean formatRequired) {
     if (isPendingReset()) {
       return C.RESULT_NOTHING_READ;
     }
@@ -187,7 +188,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
           currentChunk.startTimeUs);
     }
     downstreamTrackFormat = trackFormat;
-    return sampleQueue.readData(formatHolder, buffer, loadingFinished, lastSeekPositionUs);
+    return sampleQueue.readData(formatHolder, buffer, formatRequired, loadingFinished,
+        lastSeekPositionUs);
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStream.java

@@ -45,8 +45,8 @@ import java.io.IOException;
   }
 
   @Override
-  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean requireFormat) {
-    return sampleStreamWrapper.readData(group, formatHolder, buffer);
+    return sampleStreamWrapper.readData(group, formatHolder, buffer, requireFormat);
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java

@@ -290,7 +290,8 @@ import java.util.LinkedList;
     chunkSource.maybeThrowError();
   }
 
-  /* package */ int readData(int group, FormatHolder formatHolder, DecoderInputBuffer buffer) {
+  /* package */ int readData(int group, FormatHolder formatHolder, DecoderInputBuffer buffer,
+      boolean requireFormat) {
     if (isPendingReset()) {
       return C.RESULT_NOTHING_READ;
     }
@@ -307,8 +308,8 @@ import java.util.LinkedList;
     }
     downstreamTrackFormat = trackFormat;
 
-    return sampleQueues.valueAt(group).readData(formatHolder, buffer, loadingFinished,
+    return sampleQueues.valueAt(group).readData(formatHolder, buffer, requireFormat,
-        lastSeekPositionUs);
+        loadingFinished, lastSeekPositionUs);
   }
 
   /* package */ void skipToKeyframeBefore(int group, long timeUs) {

library/src/main/java/com/google/android/exoplayer2/text/TextRenderer.java

@@ -189,7 +189,7 @@ public final class TextRenderer extends BaseRenderer implements Callback {
           }
         }
         // Try and read the next subtitle from the source.
-        int result = readSource(formatHolder, nextInputBuffer);
+        int result = readSource(formatHolder, nextInputBuffer, false);
         if (result == C.RESULT_BUFFER_READ) {
           if (nextInputBuffer.isEndOfStream()) {
             inputStreamEnded = true;