DrKLO/Telegram · warning · UnhandledAudioFormatException

Unhandled format: {inputAudioFormat}

Error message

Unhandled format: {inputAudioFormat}

What it means

ChannelMappingAudioProcessor.onConfigure throws UnhandledAudioFormatException when the input audio encoding is not C.ENCODING_PCM_16BIT. This processor performs channel remapping (reordering/selecting channels) on 16-bit PCM only; any other encoding (8-bit, 24-bit, 32-bit int, float, compressed) is not handled and is rejected at configuration time so the pipeline can decide whether to skip the processor or fail playback.

Source

Thrown at TMessagesProj/src/main/java/com/google/android/exoplayer2/audio/ChannelMappingAudioProcessor.java:57

   *
   * @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 45ab8f4308)

Solutions

1. Insert a ResamplingAudioProcessor or FloatResamplingAudioProcessor upstream to convert the input to 16-bit PCM before the ChannelMappingAudioProcessor.
2. Only enable channel mapping (setOutputChannels) when the source is known to be 16-bit PCM; disable it otherwise (leave pendingOutputChannels null so onConfigure returns NOT_SET and the processor is bypassed).
3. If the source may be hi-res, prefer an audio sink that accepts the native encoding and do remapping after a format the sink supports.

Example fix

// before: channel mapping always configured
channelMappingProcessor.setOutputChannels(new int[]{1, 0}); // applies to any encoding
// source is 24-bit PCM -> onConfigure throws UnhandledAudioFormatException
// after: only enable when source is 16-bit, else bypass
if (inputAudioFormat.encoding == C.ENCODING_PCM_16BIT) {
  channelMappingProcessor.setOutputChannels(new int[]{1, 0});
} else {
  channelMappingProcessor.setOutputChannels(null); // bypass
}

if (inputAudioFormat.encoding == C.ENCODING_PCM_16BIT) {
  channelMappingProcessor.setOutputChannels(map);
} else {
  channelMappingProcessor.setOutputChannels(null); // bypass
}

try {
  channelMappingProcessor.onConfigure(inputAudioFormat);
} catch (UnhandledAudioFormatException e) {
  // not 16-bit; route through resampler first or bypass
}

When it happens

Trigger: Feeding audio whose decoded PCM encoding is anything other than 16-bit (e.g. ENCODING_PCM_FLOAT from a float decoder, ENCODING_PCM_24BIT/32BIT hi-res source) into a ChannelMappingAudioProcessor that has pending output channels configured.

Common situations: Hi-res audio sources (24/32-bit PCM) routed through a default audio chain that includes channel mapping; enabling channel mapping on a device path where the decoder outputs float PCM; mismatch between source encoding and processor expectations after a format change mid-stream.

Related errors

• Unhandled format: {inputAudioFormat}
• Unhandled format: {inputAudioFormat}
• Unhandled format: {inputAudioFormat}
• Unhandled format: {inputAudioFormat}
• Invalid output encoding (mode={outputMode}) for: {inputForma

AI-assisted analysis of DrKLO/Telegram@45ab8f4308 (2026-08-14). Data as JSON: /api/errors/7a6a0501d9ba875b. Report an issue: GitHub.