Create utils/vad.py

utils/vad.py

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+import bisect
+import functools
+import os
+import warnings
+
+from typing import List, NamedTuple, Optional
+
+import numpy as np
+
+
+# The code below is adapted from https://github.com/snakers4/silero-vad.
+class VadOptions(NamedTuple):
+    """VAD options.
+
+    Attributes:
+      threshold: Speech threshold. Silero VAD outputs speech probabilities for each audio chunk,
+        probabilities ABOVE this value are considered as SPEECH. It is better to tune this
+        parameter for each dataset separately, but "lazy" 0.5 is pretty good for most datasets.
+      min_speech_duration_ms: Final speech chunks shorter min_speech_duration_ms are thrown out.
+      max_speech_duration_s: Maximum duration of speech chunks in seconds. Chunks longer
+        than max_speech_duration_s will be split at the timestamp of the last silence that
+        lasts more than 100ms (if any), to prevent aggressive cutting. Otherwise, they will be
+        split aggressively just before max_speech_duration_s.
+      min_silence_duration_ms: In the end of each speech chunk wait for min_silence_duration_ms
+        before separating it
+      window_size_samples: Audio chunks of window_size_samples size are fed to the silero VAD model.
+        WARNING! Silero VAD models were trained using 512, 1024, 1536 samples for 16000 sample rate.
+        Values other than these may affect model performance!!
+      speech_pad_ms: Final speech chunks are padded by speech_pad_ms each side
+    """
+
+    threshold: float = 0.5
+    min_speech_duration_ms: int = 250
+    max_speech_duration_s: float = float("inf")
+    min_silence_duration_ms: int = 2000
+    window_size_samples: int = 1024
+    speech_pad_ms: int = 400
+
+
+def get_speech_timestamps(
+    audio: np.ndarray,
+    vad_options: Optional[VadOptions] = None,
+    **kwargs,
+) -> List[dict]:
+    """This method is used for splitting long audios into speech chunks using silero VAD.
+
+    Args:
+      audio: One dimensional float array.
+      vad_options: Options for VAD processing.
+      kwargs: VAD options passed as keyword arguments for backward compatibility.
+
+    Returns:
+      List of dicts containing begin and end samples of each speech chunk.
+    """
+    if vad_options is None:
+        vad_options = VadOptions(**kwargs)
+
+    threshold = vad_options.threshold
+    min_speech_duration_ms = vad_options.min_speech_duration_ms
+    max_speech_duration_s = vad_options.max_speech_duration_s
+    min_silence_duration_ms = vad_options.min_silence_duration_ms
+    window_size_samples = vad_options.window_size_samples
+    speech_pad_ms = vad_options.speech_pad_ms
+
+    if window_size_samples not in [512, 1024, 1536]:
+        warnings.warn(
+            "Unusual window_size_samples! Supported window_size_samples:\n"
+            " - [512, 1024, 1536] for 16000 sampling_rate"
+        )
+
+    sampling_rate = 16000
+    min_speech_samples = sampling_rate * min_speech_duration_ms / 1000
+    speech_pad_samples = sampling_rate * speech_pad_ms / 1000
+    max_speech_samples = (
+        sampling_rate * max_speech_duration_s
+        - window_size_samples
+        - 2 * speech_pad_samples
+    )
+    min_silence_samples = sampling_rate * min_silence_duration_ms / 1000
+    min_silence_samples_at_max_speech = sampling_rate * 98 / 1000
+
+    audio_length_samples = len(audio)
+
+    model = get_vad_model()
+    state = model.get_initial_state(batch_size=1)
+
+    speech_probs = []
+    for current_start_sample in range(0, audio_length_samples, window_size_samples):
+        chunk = audio[current_start_sample : current_start_sample + window_size_samples]
+        if len(chunk) < window_size_samples:
+            chunk = np.pad(chunk, (0, int(window_size_samples - len(chunk))))
+        speech_prob, state = model(chunk, state, sampling_rate)
+        speech_probs.append(speech_prob)
+
+    triggered = False
+    speeches = []
+    current_speech = {}
+    neg_threshold = threshold - 0.15
+
+    # to save potential segment end (and tolerate some silence)
+    temp_end = 0
+    # to save potential segment limits in case of maximum segment size reached
+    prev_end = next_start = 0
+
+    for i, speech_prob in enumerate(speech_probs):
+        if (speech_prob >= threshold) and temp_end:
+            temp_end = 0
+            if next_start < prev_end:
+                next_start = window_size_samples * i
+
+        if (speech_prob >= threshold) and not triggered:
+            triggered = True
+            current_speech["start"] = window_size_samples * i
+            continue
+
+        if (
+            triggered
+            and (window_size_samples * i) - current_speech["start"] > max_speech_samples
+        ):
+            if prev_end:
+                current_speech["end"] = prev_end
+                speeches.append(current_speech)
+                current_speech = {}
+                # previously reached silence (< neg_thres) and is still not speech (< thres)
+                if next_start < prev_end:
+                    triggered = False
+                else:
+                    current_speech["start"] = next_start
+                prev_end = next_start = temp_end = 0
+            else:
+                current_speech["end"] = window_size_samples * i
+                speeches.append(current_speech)
+                current_speech = {}
+                prev_end = next_start = temp_end = 0
+                triggered = False
+                continue
+
+        if (speech_prob < neg_threshold) and triggered:
+            if not temp_end:
+                temp_end = window_size_samples * i
+            # condition to avoid cutting in very short silence
+            if (window_size_samples * i) - temp_end > min_silence_samples_at_max_speech:
+                prev_end = temp_end
+            if (window_size_samples * i) - temp_end < min_silence_samples:
+                continue
+            else:
+                current_speech["end"] = temp_end
+                if (
+                    current_speech["end"] - current_speech["start"]
+                ) > min_speech_samples:
+                    speeches.append(current_speech)
+                current_speech = {}
+                prev_end = next_start = temp_end = 0
+                triggered = False
+                continue
+
+    if (
+        current_speech
+        and (audio_length_samples - current_speech["start"]) > min_speech_samples
+    ):
+        current_speech["end"] = audio_length_samples
+        speeches.append(current_speech)
+
+    for i, speech in enumerate(speeches):
+        if i == 0:
+            speech["start"] = int(max(0, speech["start"] - speech_pad_samples))
+        if i != len(speeches) - 1:
+            silence_duration = speeches[i + 1]["start"] - speech["end"]
+            if silence_duration < 2 * speech_pad_samples:
+                speech["end"] += int(silence_duration // 2)
+                speeches[i + 1]["start"] = int(
+                    max(0, speeches[i + 1]["start"] - silence_duration // 2)
+                )
+            else:
+                speech["end"] = int(
+                    min(audio_length_samples, speech["end"] + speech_pad_samples)
+                )
+                speeches[i + 1]["start"] = int(
+                    max(0, speeches[i + 1]["start"] - speech_pad_samples)
+                )
+        else:
+            speech["end"] = int(
+                min(audio_length_samples, speech["end"] + speech_pad_samples)
+            )
+
+    return speeches
+
+
+def collect_chunks(audio: np.ndarray, chunks: List[dict]) -> np.ndarray:
+    """Collects and concatenates audio chunks."""
+    if not chunks:
+        return np.array([], dtype=np.float32)
+
+    return np.concatenate([audio[chunk["start"] : chunk["end"]] for chunk in chunks])
+
+
+class SpeechTimestampsMap:
+    """Helper class to restore original speech timestamps."""
+
+    def __init__(self, chunks: List[dict], sampling_rate: int, time_precision: int = 2):
+        self.sampling_rate = sampling_rate
+        self.time_precision = time_precision
+        self.chunk_end_sample = []
+        self.total_silence_before = []
+
+        previous_end = 0
+        silent_samples = 0
+
+        for chunk in chunks:
+            silent_samples += chunk["start"] - previous_end
+            previous_end = chunk["end"]
+
+            self.chunk_end_sample.append(chunk["end"] - silent_samples)
+            self.total_silence_before.append(silent_samples / sampling_rate)
+
+    def get_original_time(
+        self,
+        time: float,
+        chunk_index: Optional[int] = None,
+    ) -> float:
+        if chunk_index is None:
+            chunk_index = self.get_chunk_index(time)
+
+        total_silence_before = self.total_silence_before[chunk_index]
+        return round(total_silence_before + time, self.time_precision)
+
+    def get_chunk_index(self, time: float) -> int:
+        sample = int(time * self.sampling_rate)
+        return min(
+            bisect.bisect(self.chunk_end_sample, sample),
+            len(self.chunk_end_sample) - 1,
+        )
+
+
+@functools.lru_cache
+def get_vad_model():
+    """Returns the VAD model instance."""
+    asset_dir = os.path.join(os.path.dirname(__file__), "assets")
+    path = os.path.join(asset_dir, "silero_vad.onnx")
+    return SileroVADModel(path)
+
+
+class SileroVADModel:
+    def __init__(self, path):
+        try:
+            import onnxruntime
+        except ImportError as e:
+            raise RuntimeError(
+                "Applying the VAD filter requires the onnxruntime package"
+            ) from e
+
+        opts = onnxruntime.SessionOptions()
+        opts.inter_op_num_threads = 1
+        opts.intra_op_num_threads = 1
+        opts.log_severity_level = 4
+
+        self.session = onnxruntime.InferenceSession(
+            path,
+            providers=["CPUExecutionProvider"],
+            sess_options=opts,
+        )
+
+    def get_initial_state(self, batch_size: int):
+        h = np.zeros((2, batch_size, 64), dtype=np.float32)
+        c = np.zeros((2, batch_size, 64), dtype=np.float32)
+        return h, c
+
+    def __call__(self, x, state, sr: int):
+        if len(x.shape) == 1:
+            x = np.expand_dims(x, 0)
+        if len(x.shape) > 2:
+            raise ValueError(
+                f"Too many dimensions for input audio chunk {len(x.shape)}"
+            )
+        if sr / x.shape[1] > 31.25:
+            raise ValueError("Input audio chunk is too short")
+
+        h, c = state
+
+        ort_inputs = {
+            "input": x,
+            "h": h,
+            "c": c,
+            "sr": np.array(sr, dtype="int64"),
+        }
+
+        out, h, c = self.session.run(None, ort_inputs)
+        state = (h, c)
+
+        return out, state