Training on CommonVoice standard recipe crashes

I was training ASR model using CommonVoice recipe from here: https://github.com/speechbrain/speechbrain/blob/develop/recipes/CommonVoice/ASR/seq2seq/hparams/train_en.yaml

After 920 iterations, training crashed with the following error:

Traceback (most recent call last):
  File "/research_shared/home/eugene/speechbrain/recipes/CommonVoice/ASR/seq2seq/train.py", line 333, in <module>
    asr_brain.fit(
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/speechbrain/core.py", line 1011, in fit
    for batch in t:
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/tqdm/std.py", line 1178, in __iter__
    for obj in iterable:
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/utils/data/dataloader.py", line 517, in __next__
    data = self._next_data()
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/utils/data/dataloader.py", line 1199, in _next_data
    return self._process_data(data)
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/utils/data/dataloader.py", line 1225, in _process_data
    data.reraise()
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/_utils.py", line 429, in reraise
    raise self.exc_type(msg)
AssertionError: Caught AssertionError in DataLoader worker process 2.
Original Traceback (most recent call last):
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/utils/data/_utils/worker.py", line 202, in _worker_loop
    data = fetcher.fetch(index)
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/torch/utils/data/_utils/fetch.py", line 47, in fetch
    return self.collate_fn(data)
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/speechbrain/dataio/batch.py", line 124, in __init__
    padded = PaddedData(*padding_func(values, **padding_kwargs))
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/speechbrain/utils/data_utils.py", line 414, in batch_pad_right
    padded, valid_percent = pad_right_to(
  File "/research_shared/home/eugene/miniconda/envs/speechbrain/lib/python3.9/site-packages/speechbrain/utils/data_utils.py", line 342, in pad_right_to
    assert len(target_shape) == tensor.ndim
AssertionError

When running with -O flag, got the following error:

...
   File "/research_shared/home/eugene/speechbrain/speechbrain/utils/data_utils.py", line 420, in batch_pad_right
    batched = torch.stack(batched)
RuntimeError: stack expects each tensor to be equal size, but got [131328] at entry 0 and [131328, 1] at entry 8

Tried both the latest develop branch and v0.5.5 PyPI installation, got the same error.

[TParcollet]

@EugKar Could you try to add this code and let me know if it works ?

if info.num_channels > 1:
    sig = torch.mean(sig, dim=1)

(On the audio_pipeline function).

[TParcollet]

Right, this is something I need to fix. The problem is simple: For some reason, CommonVoice has stereo files. I will fix this ASAP.