content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.google.android.exoplayer2.ext.flac;
  
  import android.os.Handler;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.audio.AudioProcessor;
  import com.google.android.exoplayer2.audio.AudioRendererEventListener;
  import com.google.android.exoplayer2.audio.AudioSink;
  import com.google.android.exoplayer2.audio.DecoderAudioRenderer;
  import com.google.android.exoplayer2.decoder.CryptoConfig;
  import com.google.android.exoplayer2.extractor.FlacStreamMetadata;
  import com.google.android.exoplayer2.util.MimeTypes;
  import com.google.android.exoplayer2.util.TraceUtil;
  import com.google.android.exoplayer2.util.Util;
  
  /** Decodes and renders audio using the native Flac decoder. */
  public final class LibflacAudioRenderer extends DecoderAudioRenderer<FlacDecoder> {
  
    private static final String TAG = "LibflacAudioRenderer";
    private static final int NUM_BUFFERS = 16;
    private static final int STREAM_MARKER_SIZE = 4;
    private static final int METADATA_BLOCK_HEADER_SIZE = 4;
  
    public LibflacAudioRenderer() {
      this(/* eventHandler= */ null, /* eventListener= */ null);
    }
  
    /**
     * Creates an instance.
     *
     * @param eventHandler A handler to use when delivering events to {@code eventListener}. May be
     *     null if delivery of events is not required.
     * @param eventListener A listener of events. May be null if delivery of events is not required.
     * @param audioProcessors Optional {@link AudioProcessor}s that will process audio before output.
     */
    public LibflacAudioRenderer(
        @Nullable Handler eventHandler,
        @Nullable AudioRendererEventListener eventListener,
        AudioProcessor... audioProcessors) {
      super(eventHandler, eventListener, audioProcessors);
    }
  
    /**
     * Creates an instance.
     *
     * @param eventHandler A handler to use when delivering events to {@code eventListener}. May be
     *     null if delivery of events is not required.
     * @param eventListener A listener of events. May be null if delivery of events is not required.
     * @param audioSink The sink to which audio will be output.
     */
    public LibflacAudioRenderer(
        @Nullable Handler eventHandler,
        @Nullable AudioRendererEventListener eventListener,
        AudioSink audioSink) {
      super(eventHandler, eventListener, audioSink);
    }
  
    @Override
    public String getName() {
      return TAG;
    }
  
    @Override
    protected @C.FormatSupport int supportsFormatInternal(Format format) {
      if (!FlacLibrary.isAvailable()
          || !MimeTypes.AUDIO_FLAC.equalsIgnoreCase(format.sampleMimeType)) {
        return C.FORMAT_UNSUPPORTED_TYPE;
      }
      // Compute the format that the FLAC decoder will output.
      Format outputFormat;
      if (format.initializationData.isEmpty()) {
        // The initialization data might not be set if the format was obtained from a manifest (e.g.
        // for DASH playbacks) rather than directly from the media. In this case we assume
        // ENCODING_PCM_16BIT. If the actual encoding is different then playback will still succeed as
        // long as the AudioSink supports it, which will always be true when using DefaultAudioSink.
        outputFormat =
            Util.getPcmFormat(C.ENCODING_PCM_16BIT, format.channelCount, format.sampleRate);
      } else {
        int streamMetadataOffset = STREAM_MARKER_SIZE + METADATA_BLOCK_HEADER_SIZE;
        FlacStreamMetadata streamMetadata =
            new FlacStreamMetadata(format.initializationData.get(0), streamMetadataOffset);
        outputFormat = getOutputFormat(streamMetadata);
      }
      if (!sinkSupportsFormat(outputFormat)) {
        return C.FORMAT_UNSUPPORTED_SUBTYPE;
      } else if (format.cryptoType != C.CRYPTO_TYPE_NONE) {
        return C.FORMAT_UNSUPPORTED_DRM;
      } else {
        return C.FORMAT_HANDLED;
      }
    }
  
    /** {@inheritDoc} */
    @Override
    protected FlacDecoder createDecoder(Format format, @Nullable CryptoConfig cryptoConfig)
        throws FlacDecoderException {
      TraceUtil.beginSection("createFlacDecoder");
      FlacDecoder decoder =
          new FlacDecoder(NUM_BUFFERS, NUM_BUFFERS, format.maxInputSize, format.initializationData);
      TraceUtil.endSection();
      return decoder;
    }
  
    /** {@inheritDoc} */
    @Override
    protected Format getOutputFormat(FlacDecoder decoder) {
      return getOutputFormat(decoder.getStreamMetadata());
    }
  
    private static Format getOutputFormat(FlacStreamMetadata streamMetadata) {
      return Util.getPcmFormat(
          Util.getPcmEncoding(streamMetadata.bitsPerSample),
          streamMetadata.channels,
          streamMetadata.sampleRate);
    }
  }
  