google/ExoPlayer · error · UnhandledAudioFormatException

Unhandled input format:

Error message

Unhandled input format:

What it means

ChannelMappingAudioProcessor implements per-channel output mapping (setOutputChannels, e.g. stereo-to-mono downmix order control) and only supports 16-bit PCM input. During sink configuration (onConfigure), if channel mapping is active and the incoming audio is not ENCODING_PCM_16BIT, it throws UnhandledAudioFormatException so the sink/configuration layer knows this processor cannot be inserted into the chain.

Source

Thrown at library/core/src/main/java/com/google/android/exoplayer2/audio/ChannelMappingAudioProcessor.java:63

   *
   * @param outputChannels The mapping from input to output channel indices, or {@code null} to
   *     leave the input unchanged.
   */
  public void setChannelMap(@Nullable int[] outputChannels) {
    pendingOutputChannels = outputChannels;
  }

  @Override
  @CanIgnoreReturnValue
  public AudioFormat onConfigure(AudioFormat inputAudioFormat)
      throws UnhandledAudioFormatException {
    @Nullable int[] outputChannels = pendingOutputChannels;
    if (outputChannels == null) {
      return AudioFormat.NOT_SET;
    }

    if (inputAudioFormat.encoding != C.ENCODING_PCM_16BIT) {
      throw new UnhandledAudioFormatException(inputAudioFormat);
    }

    boolean active = inputAudioFormat.channelCount != outputChannels.length;
    for (int i = 0; i < outputChannels.length; i++) {
      int channelIndex = outputChannels[i];
      if (channelIndex >= inputAudioFormat.channelCount) {
        throw new UnhandledAudioFormatException(inputAudioFormat);
      }
      active |= (channelIndex != i);
    }
    return active
        ? new AudioFormat(inputAudioFormat.sampleRate, outputChannels.length, C.ENCODING_PCM_16BIT)
        : AudioFormat.NOT_SET;
  }

  @Override
  public void queueInput(ByteBuffer inputBuffer) {
    int[] outputChannels = Assertions.checkNotNull(this.outputChannels);

View on GitHub (pinned to dd430f7053)

Solutions

1. Clear the mapping when playing non-16-bit content: player.setAudioAttributes(...)/ DefaultAudioSink without setChannelMapping, or unset it via track selection parameters.
2. Convert the stream to 16-bit PCM upstream (e.g. disable float output so the decoding chain outputs ENCODING_PCM_16BIT).
3. Wrap sink configuration in try/catch for ConfigurationException/UnhandledAudioFormatException and rebuild the sink without channel mapping before retrying.
4. Verify the media's actual PCM encoding via MediaFormat/Format before applying channel mapping.

Example fix

// before
AudioSink sink = new DefaultAudioSink.Builder(ctx)
    .setChannelMapping(new int[] {0}) // force mono
    .build();

// after — only map channels for 16-bit content
AudioSink.Builder builder = new DefaultAudioSink.Builder(ctx);
if (isPcm16BitContent) {
  builder.setChannelMapping(new int[] {0});
}
AudioSink sink = builder.build();

static int[] safeChannelMapping(int[] requested, @C.PcmEncoding int encoding,
                                int inputChannelCount) {
  if (encoding != C.ENCODING_PCM_16BIT) return null; // processor inactive
  int[] valid = new int[requested.length];
  for (int i = 0; i < requested.length; i++) {
    if (requested[i] >= inputChannelCount) return null; // would throw
    valid[i] = requested[i];
  }
  return valid;
}

try {
  sinkBuilder.setChannelMapping(mapping).build();
} catch (Exception e) { // UnhandledAudioFormatException surfaces as ConfigurationException
  sinkBuilder.setChannelMapping(null).build(); // rebuild without mapping
}

When it happens

Trigger: Calling DefaultAudioSink.Builder.setChannelMapping(int[]) (directly or via DefaultTrackSelector parameters like setAudioChannelCountOverrides / ChannelMappingParameters) and then playing audio whose PCM encoding is 24-bit, 32-bit, or float rather than 16-bit.

Common situations: Apps using ChannelMappingAudioProcessor with high-resolution PCM streams; enabling audio offload or float output while channel mapping is set; forgetting to clear the mapping when switching between 16-bit and high-res content in a playlist.

Related errors

• Unhandled input format: {inputAudioFormat}
• Unhandled input format: {inputAudioFormat}
• Unhandled input format: {inputAudioFormat}
• Unhandled input format: ${audioFormat}
• Unhandled input format: {audioFormat}

AI-assisted analysis of google/ExoPlayer@dd430f7053 (2026-08-14). Data as JSON: /api/errors/60c8fe6a8734ff64. Report an issue: GitHub.