Fix Dackka/Metalava errors in av1, flac, ffmpeg, midi, and opus modules

This uses `@hide` on `protected final` methods to hide them from Dackka
javadoc generation, since these methods are inaccessible to developers
anyway. These symbols will still (currently) be included in artefacts
distributed on Maven (because we don't run Metalava as part of
generating these artefacts).

In some cases I had to change the visibility/finality of methods to make
them `protected final` before adding the `@hide` annotation (but
the impact should be very low, since most of these methods were either
already unusable by app developers, or they shouldn't have been used).

#minor-release

PiperOrigin-RevId: 487472907

libraries/decoder_av1/src/main/java/androidx/media3/decoder/av1/Libgav1VideoRenderer.java

@@ -140,8 +140,13 @@ public class Libgav1VideoRenderer extends DecoderVideoRenderer {
         C.FORMAT_HANDLED, ADAPTIVE_SEAMLESS, TUNNELING_NOT_SUPPORTED);
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
-  protected Gav1Decoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
+  protected final Gav1Decoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
       throws Gav1DecoderException {
     TraceUtil.beginSection("createGav1Decoder");
     int initialInputBufferSize =

libraries/decoder_ffmpeg/src/main/java/androidx/media3/decoder/ffmpeg/FfmpegAudioRenderer.java

@@ -106,10 +106,15 @@ public final class FfmpegAudioRenderer extends DecoderAudioRenderer<FfmpegAudioD
   }
 
   @Override
-  public final @AdaptiveSupport int supportsMixedMimeTypeAdaptation() {
+  public @AdaptiveSupport int supportsMixedMimeTypeAdaptation() {
     return ADAPTIVE_NOT_SEAMLESS;
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
   protected FfmpegAudioDecoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
       throws FfmpegDecoderException {
@@ -123,8 +128,13 @@ public final class FfmpegAudioRenderer extends DecoderAudioRenderer<FfmpegAudioD
     return decoder;
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
-  public Format getOutputFormat(FfmpegAudioDecoder decoder) {
+  protected Format getOutputFormat(FfmpegAudioDecoder decoder) {
     Assertions.checkNotNull(decoder);
     return new Format.Builder()
         .setSampleMimeType(MimeTypes.AUDIO_RAW)

libraries/decoder_flac/src/main/java/androidx/media3/decoder/flac/LibflacAudioRenderer.java

@@ -108,6 +108,11 @@ public final class LibflacAudioRenderer extends DecoderAudioRenderer<FlacDecoder
     }
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
   protected FlacDecoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
       throws FlacDecoderException {
@@ -118,6 +123,11 @@ public final class LibflacAudioRenderer extends DecoderAudioRenderer<FlacDecoder
     return decoder;
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
   protected Format getOutputFormat(FlacDecoder decoder) {
     return getOutputFormat(decoder.getStreamMetadata());

libraries/decoder_opus/src/main/java/androidx/media3/decoder/opus/LibopusAudioRenderer.java

@@ -95,8 +95,13 @@ public class LibopusAudioRenderer extends DecoderAudioRenderer<OpusDecoder> {
     }
   }
 
+  /**
+   * {@inheritDoc}
+   *
+   * @hide
+   */
   @Override
-  protected OpusDecoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
+  protected final OpusDecoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
       throws OpusDecoderException {
     TraceUtil.beginSection("createOpusDecoder");
     @SinkFormatSupport
@@ -121,8 +126,13 @@ public class LibopusAudioRenderer extends DecoderAudioRenderer<OpusDecoder> {
     return decoder;
   }
 
+  /**
+   * {@inheritDoc} g
+   *
+   * @hide
+   */
   @Override
-  protected Format getOutputFormat(OpusDecoder decoder) {
+  protected final Format getOutputFormat(OpusDecoder decoder) {
     @C.PcmEncoding
     int pcmEncoding = decoder.outputFloat ? C.ENCODING_PCM_FLOAT : C.ENCODING_PCM_16BIT;
     return Util.getPcmFormat(pcmEncoding, decoder.channelCount, OpusDecoder.SAMPLE_RATE);