Prevent audio pops on audio format change. We'd like to switch opus audio…

Prevent audio pops on audio format change. We'd like to switch opus audio bitrates in the middle of playback based on network conditions.

Changing between different bitrates on the same codec should not require decoder initialization.

PiperOrigin-RevId: 267208043

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

@@ -361,6 +361,17 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
         null, null, 0, null);
   }
 
+  /**
+   * Returns whether the existing decoder can be kept for a new format.
+   *
+   * @param oldFormat The previous format.
+   * @param newFormat The new format.
+   * @return True if the existing decoder can be kept.
+   */
+  protected boolean canKeepCodec(Format oldFormat, Format newFormat) {
+    return false;
+  }
+
   private boolean drainOutputBuffer() throws ExoPlaybackException, AudioDecoderException,
       AudioSink.ConfigurationException, AudioSink.InitializationException,
       AudioSink.WriteException {
@@ -689,14 +700,16 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       }
     }
 
-    if (decoderReceivedBuffers) {
-      // Signal end of stream and wait for any final output buffers before re-initialization.
-      decoderReinitializationState = REINITIALIZATION_STATE_SIGNAL_END_OF_STREAM;
-    } else {
-      // There aren't any final output buffers, so release the decoder immediately.
-      releaseDecoder();
-      maybeInitDecoder();
-      audioTrackNeedsConfigure = true;
+    if (!canKeepCodec(oldFormat, inputFormat)) {
+      if (decoderReceivedBuffers) {
+        // Signal end of stream and wait for any final output buffers before re-initialization.
+        decoderReinitializationState = REINITIALIZATION_STATE_SIGNAL_END_OF_STREAM;
+      } else {
+        // There aren't any final output buffers, so release the decoder immediately.
+        releaseDecoder();
+        maybeInitDecoder();
+        audioTrackNeedsConfigure = true;
+      }
     }
 
     encoderDelay = inputFormat.encoderDelay;