stage1_dataset codec=mock input_roots=/workspace/datasets/librispeech/LibriSpeech/train-clean-100,/workspace/datasets/librispeech/LibriSpeech/train-clean-360 train_examples=259804 val_examples=5302 train_manifest=/workspace/kafka_duplex_data/stage1_trainclean460/train.stage1.jsonl val_manifest=/workspace/kafka_duplex_data/stage1_trainclean460/val.stage1.jsonl