HuggingFace audio dataset

(Generic) HuggingFace dataset in RETURNN: https://github.com/rwth-i6/returnn/issues/1257

(The underlying format is Arrow. (Parquet is another binary format supported, but not optimized for reading speed.))

HuggingFace audio datasets have some special structure. https://huggingface.co/docs/hub/en/datasets-audio

Examples: https://huggingface.co/datasets/openslr/librispeech_asr

{'chapter_id': 141231,
 'file': '/home/albert/.cache/.../dev_clean/1272/141231/1272-141231-0000.flac',
 'audio': {
    'array': array([-0.00048828, -0.00018311, -0.00137329, ...,  0.00079346, 0.00091553,  0.00085449], dtype=float32),
    'sampling_rate': 16000
 },
 'id': '1272-141231-0000',
 'speaker_id': 1272,
 'text': 'A MAN SAID TO THE UNIVERSE SIR I EXIST'}

https://huggingface.co/datasets/speechcolab/gigaspeech

{
    'segment_id': 'YOU0000000315_S0000660', 
    'speaker': 'N/A', 
    'text': "AS THEY'RE LEAVING <COMMA> CAN KASH PULL ZAHRA ASIDE REALLY QUICKLY <QUESTIONMARK>", 
    'audio': 
        {
            # in streaming mode 'path' will be 'xs_chunks_0000/YOU0000000315_S0000660.wav'
            'path': '/home/user/.cache/huggingface/datasets/downloads/extracted/9d48cf31/xs_chunks_0000/YOU0000000315_S0000660.wav', 
            'array': array([0.0005188 , 0.00085449, 0.00012207, ..., 0.00125122, 0.00076294, 0.00036621], dtype=float32), 
            'sampling_rate': 16000
        }, 
    'begin_time': 2941.889892578125, 
    'end_time': 2945.070068359375, 
    'audio_id': 'YOU0000000315', 
    'title': 'Return to Vasselheim | Critical Role: VOX MACHINA | Episode 43', 
    'url': 'https://www.youtube.com/watch?v=zr2n1fLVasU', 
    'source': 2, 
    'category': 24,
    'original_full_path': 'audio/youtube/P0004/YOU0000000315.opus'
}