Trying to define a custom transform block that converts audio file to tensor. But encountering a series of errors.
Custom Transform
import soundfile as sf
class AudioTransform(Transform):
def __init__(self, period, stride):
self.period = period
self.stride = stride
self.sr = 48000
def encodes(self, record_id):
if (data_dir/f'train/{record_id}.flac').is_file():
y, sr = sf.read(data_dir/f'train/{record_id}.flac')
else:
y, sr = sf.read(data_dir/f'test/{record_id}.flac')
y_ = []
i = 0
effective_length = self.period * self.sr
stride = self.stride * self.sr
y = np.stack([y[i:i+effective_length].astype(np.float32) for i in range(0, 60*self.sr+stride-effective_length, stride)])
return torch.tensor(y).cuda()
def AudioBlock(): return TransformBlock(type_tfms=AudioTransform(period=10, stride=5).encodes)
Usage
data = DataBlock(blocks=(AudioBlock, MultiCategoryBlock(vocab=[str(i) for i in range(24)])),
splitter=IndexSplitter(val_index),
get_x=ColReader('recording_id'),
get_y=ColReader('species_id', label_delim=' ')
)
dls = data.dataloaders(train_tp,bs=16, worker=1)
learn = Learner(dls, model, metrics=[lwlrap],
loss_func=nn.BCELoss(),
opt_func=Adam)
learn.fit(20, lr)
Usage block produces
RuntimeError: Cannot re-initialize CUDA in forked subprocess. To use CUDA with multiprocessing, you must use the 'spawn' start method
Error fix attempt 1:
If I remove the content of AudioTransform.encodes and just return the input like below, the CUDA multiprocessing error goes away
def encodes(self, record_id):
return record_id
Can someone help me understand why ?
Error fix attempt 2:
Use
torch.multiprocessing.set_start_method('spawn', force=True)
as suggested by the error message. The CUDA multiprocessing error goes away but I get this new error relating to picking my AudioTransform.encodes function above
Question:
- How do I disable all form of multiprocessing in both torch and FastAI ?
- Any Idea on how to fix the CUDA multiprocessing error and the pickling error without disable multiprocessing ?
3.What is wrong with the content ofAudioTransform.encodes? Why does removal of function body suppress the CUDA multiprocessing error ?