add whisper_live module

This commit is contained in:
makaveli10
2023-08-02 16:13:42 +08:00
parent 9cb97aa1ba
commit 242d49d8c5
4 changed files with 284 additions and 259 deletions
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import os
import argparse
import wave
import numpy as np
import scipy
import ffmpeg
import pyaudio
import threading
import textwrap
import json
import websocket
def resample(file: str, sr: int = 16000):
"""
# https://github.com/openai/whisper/blob/7858aa9c08d98f75575035ecd6481f462d66ca27/whisper/audio.py#L22
Open an audio file and read as mono waveform, resampling as necessary,
save the resampled audio
Parameters
----------
file: str
The audio file to open
sr: int
The sample rate to resample the audio if necessary
"""
try:
# This launches a subprocess to decode audio while down-mixing and resampling as necessary.
# Requires the ffmpeg CLI and `ffmpeg-python` package to be installed.
out, _ = (
ffmpeg.input(file, threads=0)
.output("-", format="s16le", acodec="pcm_s16le", ac=1, ar=sr)
.run(cmd=["ffmpeg", "-nostdin"], capture_stdout=True, capture_stderr=True)
)
except ffmpeg.Error as e:
raise RuntimeError(f"Failed to load audio: {e.stderr.decode()}") from e
np_buffer = np.frombuffer(out, dtype=np.int16)
resampled_file = f"{file.split('.')[0]}_resampled.wav"
scipy.io.wavfile.write(resampled_file, sr, np_buffer.astype(np.int16))
return resampled_file
class Client:
CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 16000
RECORD_SECONDS = 60000
START_RECORDING = False
multilingual = False
language = None
task = "transcribe"
def __init__(self, host=None, port=None, is_multilingual=False, lang=None, translate=False):
Client.multilingual = is_multilingual
Client.language = lang if is_multilingual else "en"
if translate:
Client.task = "translate"
self.timestamp_offset = 0.0
self.audio_bytes = None
self.p = pyaudio.PyAudio()
self.stream = self.p.open(format=self.FORMAT,
channels=self.CHANNELS,
rate=self.RATE,
input=True,
frames_per_buffer=self.CHUNK)
# create websocket connection
if host is not None and port is not None:
socket_url = f"ws://{host}:{port}"
self.client_socket = websocket.WebSocketApp(socket_url,
on_open=Client.on_open,
on_message=Client.on_message,
on_error=Client.on_error,
on_close=Client.on_close)
else:
print("[ERROR]: No host or port specified.")
return
# start websocket client in a thread
self.ws_thread = threading.Thread(target=self.client_socket.run_forever)
self.ws_thread.setDaemon(True)
self.ws_thread.start()
self.frames = b""
print("[INFO]: * recording")
@staticmethod
def on_message(ws, message):
message = json.loads(message)
if message == "SERVER_READY":
Client.START_RECORDING = True
return
if isinstance(message, dict):
Client.language = message.get("language")
lang_prob = message.get("language_prob")
print(f"[INFO]: Server detected language {Client.language} with probability {lang_prob}")
return
text = []
if len(message):
for seg in message:
if len(text):
if text[-1] != seg["text"]:
text.append(seg["text"])
else:
text.append(seg["text"])
if len(text) > 3:
text = text[-3:]
wrapper = textwrap.TextWrapper(width=60)
word_list = wrapper.wrap(text="".join(text))
# Print each line.
if os.name=='nt':
os.system('cls')
else:
os.system('clear')
for element in word_list:
print(element)
@staticmethod
def on_error(ws, error):
print(error)
@staticmethod
def on_close(ws, close_status_code, close_msg):
print(f"[INFO]: Websocket connection closed.")
@staticmethod
def on_open(ws):
print(Client.multilingual, Client.language, Client.task)
print("[INFO]: Opened connection")
ws.send(json.dumps({
'multilingual': Client.multilingual,
'language': Client.language,
'task': Client.task
}))
@staticmethod
def bytes_to_float_array(audio_bytes):
raw_data = np.frombuffer(
buffer=audio_bytes, dtype=np.int16
)
return raw_data.astype(np.float32) / 32768.0
def send_packet_to_server(self, message):
try:
self.client_socket.send(message, websocket.ABNF.OPCODE_BINARY)
except Exception as e:
print(e)
def play_file(self, filename):
# read audio and create pyaudio stream
self.wf = wave.open(filename, 'rb')
self.stream = self.p.open(format=self.p.get_format_from_width(self.wf.getsampwidth()),
channels=self.wf.getnchannels(),
rate=self.wf.getframerate(),
input=True,
output=True,
frames_per_buffer=self.CHUNK)
try:
while True:
data = self.wf.readframes(self.CHUNK)
if data==b'': break
audio_array = Client.bytes_to_float_array(data)
self.send_packet_to_server(audio_array.tobytes())
self.stream.write(data)
self.wf.close()
self.stream.close()
except KeyboardInterrupt:
self.wf.close()
self.stream.stop_stream()
self.stream.close()
self.p.terminate()
self.close_websocket()
print("[INFO]: Keyboard interrupt.")
def close_websocket(self):
try:
self.client_socket.close() # Close the WebSocket connection
except Exception as e:
print("[ERROR]: Error closing WebSocket:", e)
try:
self.ws_thread.join() # Wait for the WebSocket thread to finish
except Exception as e:
print("[ERROR:] Error joining WebSocket thread:", e)
def get_client_socket(self):
return self.client_socket
def write_audio_frames_to_file(self, frames, file_name):
wf = wave.open(file_name, 'wb')
wf.setnchannels(self.CHANNELS)
wf.setsampwidth(2)
wf.setframerate(self.RATE)
wf.writeframes(frames)
wf.close()
def record(self, out_file="output_recording.wav"):
n_audio_file = 0
# create dir for saving audio chunks
if not os.path.exists("chunks"):
os.makedirs("chunks", exist_ok=True)
try:
for _ in range(0, int(self.RATE / self.CHUNK * self.RECORD_SECONDS)):
data = self.stream.read(self.CHUNK)
self.frames += data
audio_array = Client.bytes_to_float_array(data)
self.send_packet_to_server(audio_array.tobytes())
# save frames if more than a minute
if len(self.frames) > 60*self.RATE:
t = threading.Thread(
target=self.write_audio_frames_to_file,
args=(self.frames[:], f"chunks/{n_audio_file}.wav", )
)
t.start()
n_audio_file += 1
self.frames = b""
except KeyboardInterrupt:
if len(self.frames):
self.write_audio_frames_to_file(
self.frames[:], f"chunks/{n_audio_file}.wav")
n_audio_file += 1
self.stream.stop_stream()
self.stream.close()
self.p.terminate()
self.close_websocket()
# combine all the audio files
self.write_output_recording(n_audio_file, out_file)
def write_output_recording(self, n_audio_file, out_file):
input_files = [f"chunks/{i}.wav" for i in range(n_audio_file) if os.path.exists(f"chunks/{i}.wav")]
wf = wave.open(out_file, 'wb')
wf.setnchannels(self.CHANNELS)
wf.setsampwidth(2)
wf.setframerate(self.RATE)
for in_file in input_files:
w = wave.open(in_file, 'rb')
while True:
data = w.readframes(self.CHUNK)
if data==b'': break
wf.writeframes(data)
w.close()
# remove this file
os.remove(in_file)
wf.close()
class TranscriptionClient:
def __init__(self, host, port, is_multilingual=False, lang=None, translate=False):
self.client = Client(host, port, is_multilingual, lang, translate)
def __call__(self, audio=None):
print("[INFO]: Waiting for server ready ...")
while not Client.START_RECORDING:
pass
print("[INFO]: Server Ready!")
if audio is not None:
resampled_file = resample(audio)
self.client.play_file(resampled_file)
else:
self.client.record()
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import websockets
import pickle, struct, time, pyaudio
import threading
import os, json
import wave
import textwrap
import logging
logging.basicConfig(level = logging.INFO)
from collections import deque
from dataclasses import dataclass
from websockets.sync.server import serve
import torch
import numpy as np
from whisper_live.transcriber import WhisperModel
class TranscriptionServer:
"""
Represents a transcription server that handles incoming audio from clients.
Attributes:
clients (dict): A dictionary to store connected clients.
"""
def __init__(self):
self.clients = {}
def recv_audio(self, websocket):
"""
Receive audio chunks from a client in an infinite loop.
Args:
websocket (WebSocket): The WebSocket connection for the client.
"""
options = websocket.recv()
options = json.loads(options)
client = ServeClient(
websocket,
multilingual=options["multilingual"],
language=options["language"],
task=options["task"],
)
self.clients[websocket] = client
while True:
try:
frame_data = websocket.recv()
frame_np = np.frombuffer(frame_data, np.float32)
self.clients[websocket].add_frames(frame_np)
except Exception as e:
self.clients[websocket].cleanup()
self.clients.pop(websocket)
logging.info("Connection Closed.")
break
def run(self, host, port):
"""
Run the transcription server.
Args:
host (str): The host address to bind the server.
port (int): The port number to bind the server.
"""
with serve(self.recv_audio, host, port) as server:
server.serve_forever()
class ServeClient:
RATE = 16000
SERVER_READY = "SERVER_READY"
def __init__(self, websocket, task="transcribe", device=None, multilingual=False, language=None):
self.data = b""
self.frames = b""
self.language = language if multilingual else "en"
self.task = task
self.transcriber = WhisperModel(
"small" if multilingual else "small.en",
device=device if device else "cuda",
compute_type="float16",
local_files_only=False,
)
# voice activity detection model
self.vad_model, _ = torch.hub.load(repo_or_dir='snakers4/silero-vad',
model='silero_vad',
force_reload=True,
onnx=True
)
self.vad_threshold = 0.4
self.timestamp_offset = 0.0
self.frames_np = None
self.frames_offset = 0.0
self.text = []
self.current_out = ''
self.prev_out = ''
self.t_start=None
self.exit = False
self.same_output_threshold = 0
self.show_prev_out_thresh = 5 # if pause(no output from whisper) show previous output for 5 seconds
self.add_pause_thresh = 3 # add a blank to segment list as a pause(no speech) for 3 seconds
self.transcript = []
self.send_last_n_segments = 10
# text formatting
self.wrapper = textwrap.TextWrapper(width=50)
self.pick_previous_segments = 2
# threading
self.websocket = websocket
self.trans_thread = threading.Thread(target=self.speech_to_text)
self.trans_thread.start()
self.websocket.send(json.dumps(self.SERVER_READY))
def fill_output(self, output):
"""
Format output with current and previous complete segments
into two lines of 50 characters.
Args:
output(str): current incomplete segment
Returns:
transcription wrapped in two lines
"""
text = ''
pick_prev = min(len(self.text), self.pick_previous_segments)
for seg in self.text[-pick_prev:]:
# discard everything before a 3 second pause
if seg == '':
text = ''
else:
text += seg
wrapped = "".join(text + output)
return wrapped
def add_frames(self, frame_np):
try:
speech_prob = self.vad_model(torch.from_numpy(frame_np.copy()), self.RATE).item()
if speech_prob < self.vad_threshold:
return
except Exception as e:
logging.error(e)
return
if self.frames_np is not None and self.frames_np.shape[0] > 45*self.RATE:
self.frames_offset += 30.0
self.frames_np = self.frames_np[int(30*self.RATE):]
if self.frames_np is None:
self.frames_np = frame_np.copy()
else:
self.frames_np = np.concatenate((self.frames_np, frame_np), axis=0)
def speech_to_text(self):
"""
Process audio stream in an infinite loop.
"""
# detect language
if self.language is None:
# wait for 30s of audio
while self.frames_np is None or self.frames_np.shape[0] < 30*self.RATE:
time.sleep(1)
input_bytes = self.frames_np[-30*self.RATE:].copy()
self.frames_np = None
duration = input_bytes.shape[0] / self.RATE
self.language, lang_prob = self.transcriber.transcribe(
input_bytes,
initial_prompt=None,
language=self.language,
task=self.task
)
logging.info(f"Detected language {self.language} with probability {lang_prob}")
self.websocket.send(json.dumps({"language": self.language, "language_prob": lang_prob}))
while True:
if self.exit:
logging.info("Exiting speech to text thread")
break
if self.frames_np is None:
continue
# clip audio if the current chunk exceeds 30 seconds, this basically implies that
# no valid segment for the last 30 seconds from whisper
if self.frames_np[int((self.timestamp_offset - self.frames_offset)*self.RATE):].shape[0] > 25 * self.RATE:
duration = self.frames_np.shape[0] / self.RATE
self.timestamp_offset = self.frames_offset + duration - 5
samples_take = max(0, (self.timestamp_offset - self.frames_offset)*self.RATE)
input_bytes = self.frames_np[int(samples_take):].copy()
duration = input_bytes.shape[0] / self.RATE
if duration<1.0:
continue
try:
input_sample = input_bytes.copy()
# set previous complete segment as initial prompt
if len(self.text) and self.text[-1] != '':
initial_prompt = self.text[-1]
else:
initial_prompt = None
# whisper transcribe with prompt
result = self.transcriber.transcribe(
input_sample,
initial_prompt=initial_prompt,
language=self.language,
task=self.task
)
if len(result):
self.t_start = None
last_segment = self.update_segments(result, duration)
if len(self.transcript) < self.send_last_n_segments:
segments = self.transcript
else:
segments = self.transcript[-self.send_last_n_segments:]
if last_segment is not None:
segments = segments + [last_segment]
try:
self.websocket.send(json.dumps(segments))
except Exception as e:
logging.info(f"[ERROR]: {e}")
else:
# show previous output if there is pause i.e. no output from whisper
segments = []
if self.t_start is None: self.t_start = time.time()
if time.time() - self.t_start < self.show_prev_out_thresh:
if len(self.transcript) < self.send_last_n_segments:
segments = self.transcript
else:
segments = self.transcript[-self.send_last_n_segments:]
# add a blank if there is no speech for 3 seconds
if len(self.text) and self.text[-1] != '':
if time.time() - self.t_start > self.add_pause_thresh:
self.text.append('')
try:
self.websocket.send(json.dumps(segments))
except Exception as e:
logging.info(f"[INFO]: {e}")
except Exception as e:
logging.info(f"[INFO]: {e}")
time.sleep(0.01)
def update_segments(self, segments, duration):
"""
Processes the segments from whisper. Appends all the segments to the list
except for the last segment assuming that it is incomplete.
Args:
segments(dict) : dictionary of segments as returned by whisper
duration(float): duration of the current chunk
Returns:
transcription for the current chunk
"""
offset = None
self.current_out = ''
last_segment = None
# process complete segments
if len(segments) > 1:
for i, s in enumerate(segments[:-1]):
text_ = s.text
self.text.append(text_)
start, end = self.timestamp_offset + s.start, self.timestamp_offset + min(duration, s.end)
self.transcript.append(
{
'start': start,
'end': end,
'text': text_
}
)
offset = min(duration, s.end)
self.current_out += segments[-1].text
last_segment = {
'start': self.timestamp_offset + segments[-1].start,
'end': self.timestamp_offset + min(duration, segments[-1].end),
'text': self.current_out
}
# if same incomplete segment is seen multiple times then update the offset
# and append the segment to the list
if self.current_out.strip() == self.prev_out.strip() and self.current_out != '':
self.same_output_threshold += 1
else:
self.same_output_threshold = 0
if self.same_output_threshold > 5:
if not len(self.text) or self.text[-1].strip().lower()!=self.current_out.strip().lower():
self.text.append(self.current_out)
self.transcript.append(
{
'start': self.timestamp_offset,
'end': self.timestamp_offset + duration,
'text': self.current_out
}
)
self.current_out = ''
offset = duration
self.same_output_threshold = 0
last_segment = None
else:
self.prev_out = self.current_out
# update offset
if offset is not None:
self.timestamp_offset += offset
return last_segment
def cleanup(self):
logging.info("Cleaning up.")
self.exit = True
self.transcriber.destroy()
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# original https://github.com/guillaumekln/faster-whisper/blob/master/faster_whisper/transcribe.py
import itertools
import logging
import os
import zlib
import logging
from typing import BinaryIO, Iterable, List, NamedTuple, Optional, Tuple, Union
import ctranslate2
import numpy as np
import tokenizers
from faster_whisper.audio import decode_audio
from faster_whisper.feature_extractor import FeatureExtractor
from faster_whisper.tokenizer import Tokenizer
from faster_whisper.utils import download_model, format_timestamp
from faster_whisper.vad import (
SpeechTimestampsMap,
collect_chunks,
get_speech_timestamps,
)
# implement logger not available in faster_whisper==0.4.1
def get_logger():
"""Returns the module logger."""
return logging.getLogger("faster_whisper")
class Word(NamedTuple):
start: float
end: float
word: str
probability: float
class Segment(NamedTuple):
start: float
end: float
text: str
words: Optional[List[Word]]
avg_log_prob: float
no_speech_prob: float
class AudioInfo(NamedTuple):
language: str
language_probability: float
duration: float
class TranscriptionOptions(NamedTuple):
beam_size: int
best_of: int
patience: float
length_penalty: float
log_prob_threshold: Optional[float]
no_speech_threshold: Optional[float]
compression_ratio_threshold: Optional[float]
condition_on_previous_text: bool
temperatures: List[float]
initial_prompt: Optional[str]
prefix: Optional[str]
suppress_blank: bool
suppress_tokens: Optional[List[int]]
without_timestamps: bool
max_initial_timestamp: float
word_timestamps: bool
prepend_punctuations: str
append_punctuations: str
class WhisperModel:
def __init__(
self,
model_size_or_path: str,
device: str = "auto",
device_index: Union[int, List[int]] = 0,
compute_type: str = "default",
cpu_threads: int = 0,
num_workers: int = 1,
download_root: Optional[str] = None,
local_files_only: bool = True,
):
"""Initializes the Whisper model.
Args:
model_size_or_path: Size of the model to use (tiny, tiny.en, base, base.en,
small, small.en, medium, medium.en, large-v1, or large-v2) or a path to a converted
model directory. When a size is configured, the converted model is downloaded
from the Hugging Face Hub.
device: Device to use for computation ("cpu", "cuda", "auto").
device_index: Device ID to use.
The model can also be loaded on multiple GPUs by passing a list of IDs
(e.g. [0, 1, 2, 3]). In that case, multiple transcriptions can run in parallel
when transcribe() is called from multiple Python threads (see also num_workers).
compute_type: Type to use for computation.
See https://opennmt.net/CTranslate2/quantization.html.
cpu_threads: Number of threads to use when running on CPU (4 by default).
A non zero value overrides the OMP_NUM_THREADS environment variable.
num_workers: When transcribe() is called from multiple Python threads,
having multiple workers enables true parallelism when running the model
(concurrent calls to self.model.generate() will run in parallel).
This can improve the global throughput at the cost of increased memory usage.
download_root: Directory where the model should be saved. If not set, the model
is saved in the standard Hugging Face cache directory.
"""
self.logger = get_logger()
if os.path.isdir(model_size_or_path):
model_path = model_size_or_path
else:
model_path = download_model(
model_size_or_path,
local_files_only=local_files_only,
cache_dir=download_root,
)
self.model = ctranslate2.models.Whisper(
model_path,
device=device,
device_index=device_index,
compute_type=compute_type,
intra_threads=cpu_threads,
inter_threads=num_workers,
)
tokenizer_file = os.path.join(model_path, "tokenizer.json")
if os.path.isfile(tokenizer_file):
self.hf_tokenizer = tokenizers.Tokenizer.from_file(tokenizer_file)
else:
self.hf_tokenizer = tokenizers.Tokenizer.from_pretrained(
"openai/whisper-tiny" + ("" if self.model.is_multilingual else ".en")
)
self.feature_extractor = FeatureExtractor()
self.num_samples_per_token = self.feature_extractor.hop_length * 2
self.frames_per_second = (
self.feature_extractor.sampling_rate // self.feature_extractor.hop_length
)
self.tokens_per_second = (
self.feature_extractor.sampling_rate // self.num_samples_per_token
)
self.input_stride = 2
self.time_precision = 0.02
self.max_length = 448
def transcribe(
self,
audio: Union[str, BinaryIO, np.ndarray],
language: Optional[str] = None,
task: str = "transcribe",
beam_size: int = 5,
best_of: int = 5,
patience: float = 1,
length_penalty: float = 1,
temperature: Union[float, List[float], Tuple[float, ...]] = [
0.0,
0.2,
0.4,
0.6,
0.8,
1.0,
],
compression_ratio_threshold: Optional[float] = 2.4,
log_prob_threshold: Optional[float] = -1.0,
no_speech_threshold: Optional[float] = 0.6,
condition_on_previous_text: bool = True,
initial_prompt: Optional[str] = None,
prefix: Optional[str] = None,
suppress_blank: bool = True,
suppress_tokens: Optional[List[int]] = [-1],
without_timestamps: bool = False,
max_initial_timestamp: float = 1.0,
word_timestamps: bool = False,
prepend_punctuations: str = "\"'“¿([{-",
append_punctuations: str = "\"'.。,!?::”)]}、",
vad_filter: bool = False,
vad_parameters: Optional[dict] = None,
) -> Tuple[Iterable[Segment], AudioInfo]:
"""Transcribes an input file.
Arguments:
audio: Path to the input file (or a file-like object), or the audio waveform.
language: The language spoken in the audio. It should be a language code such
as "en" or "fr". If not set, the language will be detected in the first 30 seconds
of audio.
task: Task to execute (transcribe or translate).
beam_size: Beam size to use for decoding.
best_of: Number of candidates when sampling with non-zero temperature.
patience: Beam search patience factor.
length_penalty: Exponential length penalty constant.
temperature: Temperature for sampling. It can be a tuple of temperatures,
which will be successively used upon failures according to either
`compression_ratio_threshold` or `log_prob_threshold`.
compression_ratio_threshold: If the gzip compression ratio is above this value,
treat as failed.
log_prob_threshold: If the average log probability over sampled tokens is
below this value, treat as failed.
no_speech_threshold: If the no_speech probability is higher than this value AND
the average log probability over sampled tokens is below `log_prob_threshold`,
consider the segment as silent.
condition_on_previous_text: If True, the previous output of the model is provided
as a prompt for the next window; disabling may make the text inconsistent across
windows, but the model becomes less prone to getting stuck in a failure loop,
such as repetition looping or timestamps going out of sync.
initial_prompt: Optional text to provide as a prompt for the first window.
prefix: Optional text to provide as a prefix for the first window.
suppress_blank: Suppress blank outputs at the beginning of the sampling.
suppress_tokens: List of token IDs to suppress. -1 will suppress a default set
of symbols as defined in the model config.json file.
without_timestamps: Only sample text tokens.
max_initial_timestamp: The initial timestamp cannot be later than this.
word_timestamps: Extract word-level timestamps using the cross-attention pattern
and dynamic time warping, and include the timestamps for each word in each segment.
prepend_punctuations: If word_timestamps is True, merge these punctuation symbols
with the next word
append_punctuations: If word_timestamps is True, merge these punctuation symbols
with the previous word
vad_filter: Enable the voice activity detection (VAD) to filter out parts of the audio
without speech. This step is using the Silero VAD model
https://github.com/snakers4/silero-vad.
vad_parameters: Dictionary of Silero VAD parameters (see available parameters and
default values in the function `get_speech_timestamps`).
Returns:
A tuple with:
- a generator over transcribed segments
- an instance of AudioInfo
"""
sampling_rate = self.feature_extractor.sampling_rate
if not isinstance(audio, np.ndarray):
audio = decode_audio(audio, sampling_rate=sampling_rate)
duration = audio.shape[0] / sampling_rate
self.logger.info(
"Processing audio with duration %s", format_timestamp(duration)
)
if vad_filter:
vad_parameters = {} if vad_parameters is None else vad_parameters
speech_chunks = get_speech_timestamps(audio, **vad_parameters)
audio = collect_chunks(audio, speech_chunks)
self.logger.info(
"VAD filter removed %s of audio",
format_timestamp(duration - (audio.shape[0] / sampling_rate)),
)
if self.logger.isEnabledFor(logging.DEBUG):
self.logger.debug(
"VAD filter kept the following audio segments: %s",
", ".join(
"[%s -> %s]"
% (
format_timestamp(chunk["start"] / sampling_rate),
format_timestamp(chunk["end"] / sampling_rate),
)
for chunk in speech_chunks
),
)
else:
speech_chunks = None
features = self.feature_extractor(audio)
encoder_output = None
if language is None:
if not self.model.is_multilingual:
language = "en"
language_probability = 1
else:
segment = features[:, : self.feature_extractor.nb_max_frames]
encoder_output = self.encode(segment)
results = self.model.detect_language(encoder_output)
language_token, language_probability = results[0][0]
language = language_token[2:-2]
self.logger.info(
"Detected language '%s' with probability %.2f",
language,
language_probability,
)
return language, language_probability
else:
language_probability = 1
tokenizer = Tokenizer(
self.hf_tokenizer,
self.model.is_multilingual,
task=task,
language=language,
)
options = TranscriptionOptions(
beam_size=beam_size,
best_of=best_of,
patience=patience,
length_penalty=length_penalty,
log_prob_threshold=log_prob_threshold,
no_speech_threshold=no_speech_threshold,
compression_ratio_threshold=compression_ratio_threshold,
condition_on_previous_text=condition_on_previous_text,
temperatures=(
temperature if isinstance(temperature, (list, tuple)) else [temperature]
),
initial_prompt=initial_prompt,
prefix=prefix,
suppress_blank=suppress_blank,
suppress_tokens=get_suppressed_tokens(tokenizer, suppress_tokens),
without_timestamps=without_timestamps,
max_initial_timestamp=max_initial_timestamp,
word_timestamps=word_timestamps,
prepend_punctuations=prepend_punctuations,
append_punctuations=append_punctuations,
)
segments = self.generate_segments(features, tokenizer, options, encoder_output)
if speech_chunks:
segments = restore_speech_timestamps(segments, speech_chunks, sampling_rate)
audio_info = AudioInfo(
language=language,
language_probability=language_probability,
duration=duration,
)
return segments
def generate_segments(
self,
features: np.ndarray,
tokenizer: Tokenizer,
options: TranscriptionOptions,
encoder_output: Optional[ctranslate2.StorageView] = None,
) -> Iterable[Segment]:
content_frames = features.shape[-1] - self.feature_extractor.nb_max_frames
seek = 0
all_tokens = []
prompt_reset_since = 0
if options.initial_prompt is not None:
initial_prompt = " " + options.initial_prompt.strip()
initial_prompt_tokens = tokenizer.encode(initial_prompt)
all_tokens.extend(initial_prompt_tokens)
all_segments = []
while seek < content_frames:
time_offset = seek * self.feature_extractor.time_per_frame
segment = features[:, seek : seek + self.feature_extractor.nb_max_frames]
segment_size = min(
self.feature_extractor.nb_max_frames, content_frames - seek
)
segment_duration = segment_size * self.feature_extractor.time_per_frame
if self.logger.isEnabledFor(logging.DEBUG):
self.logger.debug(
"Processing segment at %s", format_timestamp(time_offset)
)
previous_tokens = all_tokens[prompt_reset_since:]
prompt = self.get_prompt(
tokenizer,
previous_tokens,
without_timestamps=options.without_timestamps,
prefix=options.prefix if seek == 0 else None,
)
if encoder_output is None:
encoder_output = self.encode(segment)
result, avg_log_prob, temperature = self.generate_with_fallback(
encoder_output, prompt, tokenizer, options
)
if options.no_speech_threshold is not None:
# no voice activity check
should_skip = result.no_speech_prob > options.no_speech_threshold
if (
options.log_prob_threshold is not None
and avg_log_prob > options.log_prob_threshold
):
# don't skip if the logprob is high enough, despite the no_speech_prob
should_skip = False
if should_skip:
self.logger.debug(
"No speech threshold is met (%f > %f)",
result.no_speech_prob,
options.no_speech_threshold,
)
# fast-forward to the next segment boundary
seek += segment_size
continue
tokens = result.sequences_ids[0]
previous_seek = seek
current_segments = []
single_timestamp_ending = (
len(tokens) >= 2
and tokens[-2] < tokenizer.timestamp_begin
and tokens[-1] >= tokenizer.timestamp_begin
)
consecutive_timestamps = [
i
for i in range(len(tokens))
if i > 0
and tokens[i] >= tokenizer.timestamp_begin
and tokens[i - 1] >= tokenizer.timestamp_begin
]
if len(consecutive_timestamps) > 0:
slices = list(consecutive_timestamps)
if single_timestamp_ending:
slices.append(len(tokens))
last_slice = 0
for current_slice in slices:
sliced_tokens = tokens[last_slice:current_slice]
start_timestamp_position = (
sliced_tokens[0] - tokenizer.timestamp_begin
)
end_timestamp_position = (
sliced_tokens[-1] - tokenizer.timestamp_begin
)
start_time = (
time_offset + start_timestamp_position * self.time_precision
)
end_time = (
time_offset + end_timestamp_position * self.time_precision
)
current_segments.append(
dict(
seek=seek,
start=start_time,
end=end_time,
tokens=sliced_tokens,
)
)
last_slice = current_slice
if single_timestamp_ending:
# single timestamp at the end means no speech after the last timestamp.
seek += segment_size
else:
# otherwise, ignore the unfinished segment and seek to the last timestamp
last_timestamp_position = (
tokens[last_slice - 1] - tokenizer.timestamp_begin
)
seek += last_timestamp_position * self.input_stride
else:
duration = segment_duration
timestamps = [
token for token in tokens if token >= tokenizer.timestamp_begin
]
if len(timestamps) > 0 and timestamps[-1] != tokenizer.timestamp_begin:
last_timestamp_position = timestamps[-1] - tokenizer.timestamp_begin
duration = last_timestamp_position * self.time_precision
current_segments.append(
dict(
seek=seek,
start=time_offset,
end=time_offset + duration,
tokens=tokens,
)
)
seek += segment_size
if not options.condition_on_previous_text or temperature > 0.5:
prompt_reset_since = len(all_tokens)
if options.word_timestamps:
self.add_word_timestamps(
current_segments,
tokenizer,
encoder_output,
segment_size,
options.prepend_punctuations,
options.append_punctuations,
)
word_end_timestamps = [
w["end"] for s in current_segments for w in s["words"]
]
if not single_timestamp_ending and len(word_end_timestamps) > 0:
seek_shift = round(
(word_end_timestamps[-1] - time_offset) * self.frames_per_second
)
if seek_shift > 0:
seek = previous_seek + seek_shift
encoder_output = None
for segment in current_segments:
tokens = segment["tokens"]
text = tokenizer.decode(tokens)
if segment["start"] == segment["end"] or not text.strip():
continue
all_tokens.extend(tokens)
all_segments.append(Segment(
start=segment["start"],
end=segment["end"],
text=text,
words=(
[Word(**word) for word in segment["words"]]
if options.word_timestamps
else None
),
avg_log_prob=avg_log_prob,
no_speech_prob=result.no_speech_prob,
))
return all_segments
def encode(self, features: np.ndarray) -> ctranslate2.StorageView:
# When the model is running on multiple GPUs, the encoder output should be moved
# to the CPU since we don't know which GPU will handle the next job.
to_cpu = self.model.device == "cuda" and len(self.model.device_index) > 1
features = np.expand_dims(features, 0)
features = get_ctranslate2_storage(features)
return self.model.encode(features, to_cpu=to_cpu)
def generate_with_fallback(
self,
encoder_output: ctranslate2.StorageView,
prompt: List[int],
tokenizer: Tokenizer,
options: TranscriptionOptions,
) -> Tuple[ctranslate2.models.WhisperGenerationResult, float, float]:
result = None
avg_log_prob = None
final_temperature = None
max_initial_timestamp_index = int(
round(options.max_initial_timestamp / self.time_precision)
)
for temperature in options.temperatures:
if temperature > 0:
kwargs = {
"beam_size": 1,
"num_hypotheses": options.best_of,
"sampling_topk": 0,
"sampling_temperature": temperature,
}
else:
kwargs = {
"beam_size": options.beam_size,
"patience": options.patience,
}
final_temperature = temperature
result = self.model.generate(
encoder_output,
[prompt],
length_penalty=options.length_penalty,
max_length=self.max_length,
return_scores=True,
return_no_speech_prob=True,
suppress_blank=options.suppress_blank,
suppress_tokens=options.suppress_tokens,
max_initial_timestamp_index=max_initial_timestamp_index,
**kwargs,
)[0]
tokens = result.sequences_ids[0]
# Recover the average log prob from the returned score.
seq_len = len(tokens)
cum_log_prob = result.scores[0] * (seq_len**options.length_penalty)
avg_log_prob = cum_log_prob / (seq_len + 1)
text = tokenizer.decode(tokens).strip()
compression_ratio = get_compression_ratio(text)
needs_fallback = False
if (
options.compression_ratio_threshold is not None
and compression_ratio > options.compression_ratio_threshold
):
needs_fallback = True # too repetitive
self.logger.debug(
"Compression ratio threshold is not met with temperature %.1f (%f > %f)",
temperature,
compression_ratio,
options.compression_ratio_threshold,
)
if (
options.log_prob_threshold is not None
and avg_log_prob < options.log_prob_threshold
):
needs_fallback = True # average log probability is too low
self.logger.debug(
"Log probability threshold is not met with temperature %.1f (%f < %f)",
temperature,
avg_log_prob,
options.log_prob_threshold,
)
if not needs_fallback:
break
return result, avg_log_prob, final_temperature
def get_prompt(
self,
tokenizer: Tokenizer,
previous_tokens: List[int],
without_timestamps: bool = False,
prefix: Optional[str] = None,
) -> List[int]:
prompt = []
if previous_tokens:
prompt.append(tokenizer.sot_prev)
prompt.extend(previous_tokens[-(self.max_length // 2 - 1) :])
prompt.extend(tokenizer.sot_sequence)
if without_timestamps:
prompt.append(tokenizer.no_timestamps)
if prefix:
prefix_tokens = tokenizer.encode(" " + prefix.strip())
if len(prefix_tokens) >= self.max_length // 2:
prefix_tokens = prefix_tokens[: self.max_length // 2 - 1]
prompt.extend(prefix_tokens)
return prompt
def add_word_timestamps(
self,
segments: List[dict],
tokenizer: Tokenizer,
encoder_output: ctranslate2.StorageView,
num_frames: int,
prepend_punctuations: str,
append_punctuations: str,
):
if len(segments) == 0:
return
text_tokens_per_segment = [
[token for token in segment["tokens"] if token < tokenizer.eot]
for segment in segments
]
text_tokens = list(itertools.chain.from_iterable(text_tokens_per_segment))
alignment = self.find_alignment(
tokenizer, text_tokens, encoder_output, num_frames
)
merge_punctuations(alignment, prepend_punctuations, append_punctuations)
time_offset = (
segments[0]["seek"]
* self.feature_extractor.hop_length
/ self.feature_extractor.sampling_rate
)
word_index = 0
for segment, text_tokens in zip(segments, text_tokens_per_segment):
saved_tokens = 0
words = []
while word_index < len(alignment) and saved_tokens < len(text_tokens):
timing = alignment[word_index]
if timing["word"]:
words.append(
dict(
word=timing["word"],
start=round(time_offset + timing["start"], 2),
end=round(time_offset + timing["end"], 2),
probability=timing["probability"],
)
)
saved_tokens += len(timing["tokens"])
word_index += 1
if len(words) > 0:
# adjust the segment-level timestamps based on the word-level timestamps
segment["start"] = words[0]["start"]
segment["end"] = words[-1]["end"]
segment["words"] = words
def find_alignment(
self,
tokenizer: Tokenizer,
text_tokens: List[int],
encoder_output: ctranslate2.StorageView,
num_frames: int,
median_filter_width: int = 7,
) -> List[dict]:
if len(text_tokens) == 0:
return []
result = self.model.align(
encoder_output,
tokenizer.sot_sequence,
[text_tokens],
num_frames,
median_filter_width=median_filter_width,
)[0]
text_token_probs = result.text_token_probs
alignments = result.alignments
text_indices = np.array([pair[0] for pair in alignments])
time_indices = np.array([pair[1] for pair in alignments])
words, word_tokens = tokenizer.split_to_word_tokens(
text_tokens + [tokenizer.eot]
)
word_boundaries = np.pad(np.cumsum([len(t) for t in word_tokens[:-1]]), (1, 0))
jumps = np.pad(np.diff(text_indices), (1, 0), constant_values=1).astype(bool)
jump_times = time_indices[jumps] / self.tokens_per_second
start_times = jump_times[word_boundaries[:-1]]
end_times = jump_times[word_boundaries[1:]]
word_probabilities = [
np.mean(text_token_probs[i:j])
for i, j in zip(word_boundaries[:-1], word_boundaries[1:])
]
# hack: ensure the first and second word is not longer than twice the median word duration.
# a better segmentation algorithm based on VAD should be able to replace this.
word_durations = end_times - start_times
word_durations = word_durations[word_durations.nonzero()]
if len(word_durations) > 0:
median_duration = np.median(word_durations)
max_duration = median_duration * 2
if len(word_durations) >= 2 and word_durations[1] > max_duration:
boundary = max(end_times[2] / 2, end_times[2] - max_duration)
end_times[0] = start_times[1] = boundary
if (
len(word_durations) >= 1
and end_times[0] - start_times[0] > max_duration
):
start_times[0] = max(0, end_times[0] - max_duration)
return [
dict(
word=word, tokens=tokens, start=start, end=end, probability=probability
)
for word, tokens, start, end, probability in zip(
words, word_tokens, start_times, end_times, word_probabilities
)
]
def destroy(self):
del self.model
def restore_speech_timestamps(
segments: Iterable[Segment],
speech_chunks: List[dict],
sampling_rate: int,
) -> Iterable[Segment]:
ts_map = SpeechTimestampsMap(speech_chunks, sampling_rate)
for segment in segments:
if segment.words:
words = []
for word in segment.words:
# Ensure the word start and end times are resolved to the same chunk.
chunk_index = ts_map.get_chunk_index(word.start)
word = word._replace(
start=ts_map.get_original_time(word.start, chunk_index),
end=ts_map.get_original_time(word.end, chunk_index),
)
words.append(word)
segment = segment._replace(
start=words[0].start,
end=words[-1].end,
words=words,
)
else:
segment = segment._replace(
start=ts_map.get_original_time(segment.start),
end=ts_map.get_original_time(segment.end),
)
yield segment
def get_ctranslate2_storage(segment: np.ndarray) -> ctranslate2.StorageView:
segment = np.ascontiguousarray(segment)
segment = ctranslate2.StorageView.from_array(segment)
return segment
def get_compression_ratio(text: str) -> float:
text_bytes = text.encode("utf-8")
return len(text_bytes) / len(zlib.compress(text_bytes))
def get_suppressed_tokens(tokenizer, suppress_tokens):
if not suppress_tokens or -1 in suppress_tokens:
return suppress_tokens
suppress_tokens = list(suppress_tokens)
# Ensure the following special tokens are suppressed when the user does
# not use the default set (-1).
suppress_tokens.extend(
[
tokenizer.transcribe,
tokenizer.translate,
tokenizer.sot,
tokenizer.sot_prev,
tokenizer.sot_lm,
]
)
return sorted(set(suppress_tokens))
def merge_punctuations(alignment: List[dict], prepended: str, appended: str):
# merge prepended punctuations
i = len(alignment) - 2
j = len(alignment) - 1
while i >= 0:
previous = alignment[i]
following = alignment[j]
if previous["word"].startswith(" ") and previous["word"].strip() in prepended:
# prepend it to the following word
following["word"] = previous["word"] + following["word"]
following["tokens"] = previous["tokens"] + following["tokens"]
previous["word"] = ""
previous["tokens"] = []
else:
j = i
i -= 1
# merge appended punctuations
i = 0
j = 1
while j < len(alignment):
previous = alignment[i]
following = alignment[j]
if not previous["word"].endswith(" ") and following["word"] in appended:
# append it to the previous word
previous["word"] = previous["word"] + following["word"]
previous["tokens"] = previous["tokens"] + following["tokens"]
following["word"] = ""
following["tokens"] = []
else:
i = j
j += 1