whisper-jax / processing_whisper.py
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Create processing_whisper.py
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import math
import numpy as np
from transformers import WhisperProcessor
class WhisperPrePostProcessor(WhisperProcessor):
def chunk_iter_with_batch(self, inputs, chunk_len, stride_left, stride_right, batch_size):
inputs_len = inputs.shape[0]
step = chunk_len - stride_left - stride_right
all_chunk_start_idx = np.arange(0, inputs_len, step)
num_samples = len(all_chunk_start_idx)
num_batches = math.ceil(num_samples / batch_size)
batch_idx = np.array_split(np.arange(num_samples), num_batches)
for i, idx in enumerate(batch_idx):
chunk_start_idx = all_chunk_start_idx[idx]
chunk_end_idx = chunk_start_idx + chunk_len
chunks = [inputs[chunk_start:chunk_end] for chunk_start, chunk_end in zip(chunk_start_idx, chunk_end_idx)]
processed = self.feature_extractor(
chunks, sampling_rate=self.feature_extractor.sampling_rate, return_tensors="np"
)
_stride_left = np.where(chunk_start_idx == 0, 0, stride_left)
is_last = np.where(stride_right > 0, chunk_end_idx > inputs_len, chunk_end_idx >= inputs_len)
_stride_right = np.where(is_last, 0, stride_right)
chunk_lens = [chunk.shape[0] for chunk in chunks]
strides = [
(int(chunk_l), int(_stride_l), int(_stride_r))
for chunk_l, _stride_l, _stride_r in zip(chunk_lens, _stride_left, _stride_right)
]
yield {"stride": strides, **processed}
def preprocess_batch(self, inputs, chunk_length_s=0, stride_length_s=None, batch_size=None):
stride = None
if isinstance(inputs, dict):
stride = inputs.pop("stride", None)
# Accepting `"array"` which is the key defined in `datasets` for
# better integration
if not ("sampling_rate" in inputs and ("raw" in inputs or "array" in inputs)):
raise ValueError(
"When passing a dictionary to FlaxWhisperPipline, the dict needs to contain a "
'"raw" or "array" key containing the numpy array representing the audio, and a "sampling_rate" key '
"containing the sampling rate associated with the audio array."
)
_inputs = inputs.pop("raw", None)
if _inputs is None:
# Remove path which will not be used from `datasets`.
inputs.pop("path", None)
_inputs = inputs.pop("array", None)
in_sampling_rate = inputs.pop("sampling_rate")
inputs = _inputs
if in_sampling_rate != self.feature_extractor.sampling_rate:
try:
import librosa
except ImportError as err:
raise ImportError(
"To support resampling audio files, please install 'librosa' and 'soundfile'."
) from err
inputs = librosa.resample(
inputs, orig_sr=in_sampling_rate, target_sr=self.feature_extractor.sampling_rate
)
ratio = self.feature_extractor.sampling_rate / in_sampling_rate
else:
ratio = 1
if not isinstance(inputs, np.ndarray):
raise ValueError(f"We expect a numpy ndarray as input, got `{type(inputs)}`")
if len(inputs.shape) != 1:
raise ValueError("We expect a single channel audio input for AutomaticSpeechRecognitionPipeline")
if stride is not None:
if stride[0] + stride[1] > inputs.shape[0]:
raise ValueError("Stride is too large for input")
# Stride needs to get the chunk length here, it's going to get
# swallowed by the `feature_extractor` later, and then batching
# can add extra data in the inputs, so we need to keep track
# of the original length in the stride so we can cut properly.
stride = (inputs.shape[0], int(round(stride[0] * ratio)), int(round(stride[1] * ratio)))
if chunk_length_s:
if stride_length_s is None:
stride_length_s = chunk_length_s / 6
if isinstance(stride_length_s, (int, float)):
stride_length_s = [stride_length_s, stride_length_s]
chunk_len = round(chunk_length_s * self.feature_extractor.sampling_rate)
stride_left = round(stride_length_s[0] * self.feature_extractor.sampling_rate)
stride_right = round(stride_length_s[1] * self.feature_extractor.sampling_rate)
if chunk_len < stride_left + stride_right:
raise ValueError("Chunk length must be superior to stride length")
for item in self.chunk_iter_with_batch(
inputs,
chunk_len,
stride_left,
stride_right,
batch_size,
):
yield item
else:
processed = self.feature_extractor(
inputs, sampling_rate=self.feature_extractor.sampling_rate, return_tensors="np"
)
if stride is not None:
processed["stride"] = stride
yield processed
def postprocess(self, model_outputs, return_timestamps=None, return_language=None):
# unpack the outputs from list(dict(list)) to list(dict)
model_outputs = [dict(zip(output, t)) for output in model_outputs for t in zip(*output.values())]
time_precision = self.feature_extractor.chunk_length / 1500 # max source positions = 1500
# Send the chunking back to seconds, it's easier to handle in whisper
sampling_rate = self.feature_extractor.sampling_rate
for output in model_outputs:
if "stride" in output:
chunk_len, stride_left, stride_right = output["stride"]
# Go back in seconds
chunk_len /= sampling_rate
stride_left /= sampling_rate
stride_right /= sampling_rate
output["stride"] = chunk_len, stride_left, stride_right
text, optional = self.tokenizer._decode_asr(
model_outputs,
return_timestamps=return_timestamps,
return_language=return_language,
time_precision=time_precision,
)
return {"text": text, **optional}