tensorflow/models · error · ValueError

Unknown decoder type: {}!

Error message

Unknown decoder type: {}!

What it means

Error "Unknown decoder type: {}!" thrown in tensorflow/models.

Source

Thrown at official/vision/tasks/maskrcnn.py:151

      params: exp_cfg.DataConfig,
      input_context: Optional[tf.distribute.InputContext] = None,
      dataset_fn: Optional[dataset_fn_lib.PossibleDatasetType] = None
  ) -> tf.data.Dataset:
    """Builds input dataset."""
    decoder_cfg = params.decoder.get()
    if params.decoder.type == 'simple_decoder':
      decoder = tf_example_decoder.TfExampleDecoder(
          include_mask=self._task_config.model.include_mask,
          regenerate_source_id=decoder_cfg.regenerate_source_id,
          mask_binarize_threshold=decoder_cfg.mask_binarize_threshold)
    elif params.decoder.type == 'label_map_decoder':
      decoder = tf_example_label_map_decoder.TfExampleDecoderLabelMap(
          label_map=decoder_cfg.label_map,
          include_mask=self._task_config.model.include_mask,
          regenerate_source_id=decoder_cfg.regenerate_source_id,
          mask_binarize_threshold=decoder_cfg.mask_binarize_threshold)
    else:
      raise ValueError('Unknown decoder type: {}!'.format(params.decoder.type))

    parser = maskrcnn_input.Parser(
        output_size=self.task_config.model.input_size[:2],
        min_level=self.task_config.model.min_level,
        max_level=self.task_config.model.max_level,
        num_scales=self.task_config.model.anchor.num_scales,
        aspect_ratios=self.task_config.model.anchor.aspect_ratios,
        anchor_size=self.task_config.model.anchor.anchor_size,
        rpn_match_threshold=params.parser.rpn_match_threshold,
        rpn_unmatched_threshold=params.parser.rpn_unmatched_threshold,
        rpn_batch_size_per_im=params.parser.rpn_batch_size_per_im,
        rpn_fg_fraction=params.parser.rpn_fg_fraction,
        aug_rand_hflip=params.parser.aug_rand_hflip,
        aug_rand_vflip=params.parser.aug_rand_vflip,
        aug_scale_min=params.parser.aug_scale_min,
        aug_scale_max=params.parser.aug_scale_max,
        aug_type=params.parser.aug_type,
        skip_crowd_during_training=params.parser.skip_crowd_during_training,

View on GitHub (pinned to e006f5f0d5)

Solutions

1. Use a supported decoder type: 'fpn' or 'dilated_fpn' for Mask R-CNN.
2. Check the decoder type in the model config for typos.

When it happens

Trigger: Thrown at official/vision/tasks/maskrcnn.py:151 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of tensorflow/models@e006f5f0d5 (2026-08-24). Data as JSON: /api/errors/c5763fe7d8772842. Report an issue: GitHub.