Recreate Opus decoder for stream change

The framework opus decoder discards some samples after a call to
flush(). Because we flush a decoder that is being retained across an
input format change, this means that the start of audio gets truncated
when transitioning to a new opus stream. See also
https://android.googlesource.com/platform/frameworks/av/+/refs/heads/android10-release/media/libstagefright/codecs/opus/dec/SoftOpus.cpp.

Avoid this by recreating opus decoders instead of flushing them. It
seems fine to do this for all opus decoders as reinitialization should
be cheap, OEM-provided implementations may also discard samples and
playback shouldn't be interrupted on reinitialization due to the
downstream AudioTrack buffer.

PiperOrigin-RevId: 277458759

RELEASENOTES.md

@@ -1,6 +1,11 @@
 # Release notes #
 
-### 2.10.6 (2019-10-18) ###
+### 2.10.7 ###
+
+* Fix the start of audio getting truncated when transitioning to a new
+  item in a playlist of opus streams.
+
+### 2.10.6 (2019-10-17) ###
 
 * Add `Player.onPlaybackSuppressionReasonChanged` to allow listeners to
   detect playbacks suppressions (e.g. transient audio focus loss) directly

library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java

@@ -434,13 +434,34 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     } else if (codecInfo.isSeamlessAdaptationSupported(
         oldFormat, newFormat, /* isNewFormatComplete= */ true)) {
       return KEEP_CODEC_RESULT_YES_WITHOUT_RECONFIGURATION;
-    } else if (areCodecConfigurationCompatible(oldFormat, newFormat)) {
+    } else if (canKeepCodecWithFlush(oldFormat, newFormat)) {
       return KEEP_CODEC_RESULT_YES_WITH_FLUSH;
     } else {
       return KEEP_CODEC_RESULT_NO;
     }
   }
 
+  /**
+   * Returns whether the codec can be flushed and reused when switching to a new format. Reuse is
+   * generally possible when the codec would be configured in an identical way after the format
+   * change (excluding {@link MediaFormat#KEY_MAX_INPUT_SIZE} and configuration that does not come
+   * from the {@link Format}).
+   *
+   * @param oldFormat The first format.
+   * @param newFormat The second format.
+   * @return Whether the codec can be flushed and reused when switching to a new format.
+   */
+  protected boolean canKeepCodecWithFlush(Format oldFormat, Format newFormat) {
+    // Flush and reuse the codec if the audio format and initialization data matches. For Opus, we
+    // don't flush and reuse the codec because the decoder may discard samples after flushing, which
+    // would result in audio being dropped just after a stream change (see [Internal: b/143450854]).
+    return Util.areEqual(oldFormat.sampleMimeType, newFormat.sampleMimeType)
+        && oldFormat.channelCount == newFormat.channelCount
+        && oldFormat.sampleRate == newFormat.sampleRate
+        && oldFormat.initializationDataEquals(newFormat)
+        && !MimeTypes.AUDIO_OPUS.equals(oldFormat.sampleMimeType);
+  }
+
   @Override
   public MediaClock getMediaClock() {
     return this;
@@ -818,24 +839,6 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     return format.maxInputSize;
   }
 
-  /**
-   * Returns whether two {@link Format}s will cause the same codec to be configured in an identical
-   * way, excluding {@link MediaFormat#KEY_MAX_INPUT_SIZE} and configuration that does not come from
-   * the {@link Format}.
-   *
-   * @param oldFormat The first format.
-   * @param newFormat The second format.
-   * @return Whether the two formats will cause a codec to be configured in an identical way,
-   *     excluding {@link MediaFormat#KEY_MAX_INPUT_SIZE} and configuration that does not come from
-   *     the {@link Format}.
-   */
-  protected boolean areCodecConfigurationCompatible(Format oldFormat, Format newFormat) {
-    return Util.areEqual(oldFormat.sampleMimeType, newFormat.sampleMimeType)
-        && oldFormat.channelCount == newFormat.channelCount
-        && oldFormat.sampleRate == newFormat.sampleRate
-        && oldFormat.initializationDataEquals(newFormat);
-  }
-
   /**
    * Returns the framework {@link MediaFormat} that can be used to configure a {@link MediaCodec}
    * for decoding the given {@link Format} for playback.

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecInfo.java

@@ -328,13 +328,13 @@ public final class MediaCodecInfo {
 
   /**
    * Whether the decoder supports video with a given width, height and frame rate.
-   * <p>
+   *
-   * Must not be called if the device SDK version is less than 21.
+   * <p>Must not be called if the device SDK version is less than 21.
    *
    * @param width Width in pixels.
    * @param height Height in pixels.
-   * @param frameRate Optional frame rate in frames per second. Ignored if set to
+   * @param frameRate Optional frame rate in frames per second. Ignored if set to {@link
-   *     {@link Format#NO_VALUE} or any value less than or equal to 0.
+   *     Format#NO_VALUE} or any value less than or equal to 0.
    * @return Whether the decoder supports video with the given width, height and frame rate.
    */
   @TargetApi(21)