vllm/vllm/entrypoints/openai/speech_to_text.py
Nick Hill 7992324f23
[BugFix] Use unique ids for different transcription prompts (#29372)
Signed-off-by: Nick Hill <nhill@redhat.com>
2025-11-25 06:55:16 +00:00

406 lines
16 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import asyncio
import io
import math
import time
from collections.abc import AsyncGenerator, Callable
from functools import cached_property
from typing import Literal, TypeAlias, TypeVar, cast
import numpy as np
from fastapi import Request
import vllm.envs as envs
from vllm.engine.protocol import EngineClient
from vllm.entrypoints.logger import RequestLogger
from vllm.entrypoints.openai.protocol import (
DeltaMessage,
ErrorResponse,
RequestResponseMetadata,
TranscriptionResponse,
TranscriptionResponseStreamChoice,
TranscriptionStreamResponse,
TranslationResponse,
TranslationResponseStreamChoice,
TranslationStreamResponse,
UsageInfo,
)
from vllm.entrypoints.openai.serving_engine import OpenAIServing, SpeechToTextRequest
from vllm.entrypoints.openai.serving_models import OpenAIServingModels
from vllm.inputs.data import PromptType
from vllm.logger import init_logger
from vllm.model_executor.models import SupportsTranscription
from vllm.outputs import RequestOutput
from vllm.utils.import_utils import PlaceholderModule
try:
import librosa
except ImportError:
librosa = PlaceholderModule("librosa") # type: ignore[assignment]
SpeechToTextResponse: TypeAlias = TranscriptionResponse | TranslationResponse
T = TypeVar("T", bound=SpeechToTextResponse)
logger = init_logger(__name__)
class OpenAISpeechToText(OpenAIServing):
"""Base class for speech-to-text operations like transcription and
translation."""
def __init__(
self,
engine_client: EngineClient,
models: OpenAIServingModels,
*,
request_logger: RequestLogger | None,
return_tokens_as_token_ids: bool = False,
task_type: Literal["transcribe", "translate"] = "transcribe",
log_error_stack: bool = False,
enable_force_include_usage: bool = False,
):
super().__init__(
engine_client=engine_client,
models=models,
request_logger=request_logger,
return_tokens_as_token_ids=return_tokens_as_token_ids,
log_error_stack=log_error_stack,
)
self.default_sampling_params = self.model_config.get_diff_sampling_param()
self.task_type = task_type
self.asr_config = self.model_cls.get_speech_to_text_config(
self.model_config, task_type
)
self.enable_force_include_usage = enable_force_include_usage
self.max_audio_filesize_mb = envs.VLLM_MAX_AUDIO_CLIP_FILESIZE_MB
if self.default_sampling_params:
logger.info(
"Overwriting default completion sampling param with: %s",
self.default_sampling_params,
)
@cached_property
def model_cls(self) -> type[SupportsTranscription]:
from vllm.model_executor.model_loader import get_model_cls
model_cls = get_model_cls(self.model_config)
return cast(type[SupportsTranscription], model_cls)
async def _preprocess_speech_to_text(
self,
request: SpeechToTextRequest,
audio_data: bytes,
) -> tuple[list[PromptType], float]:
# Validate request
language = self.model_cls.validate_language(request.language)
# Skip to_language validation to avoid extra logging for Whisper.
to_language = (
self.model_cls.validate_language(request.to_language)
if request.to_language
else None
)
if len(audio_data) / 1024**2 > self.max_audio_filesize_mb:
raise ValueError("Maximum file size exceeded.")
with io.BytesIO(audio_data) as bytes_:
# NOTE resample to model SR here for efficiency. This is also a
# pre-requisite for chunking, as it assumes Whisper SR.
y, sr = librosa.load(bytes_, sr=self.asr_config.sample_rate)
duration = librosa.get_duration(y=y, sr=sr)
do_split_audio = (
self.asr_config.allow_audio_chunking
and duration > self.asr_config.max_audio_clip_s
)
chunks = [y] if not do_split_audio else self._split_audio(y, int(sr))
prompts = []
for chunk in chunks:
# The model has control over the construction, as long as it
# returns a valid PromptType.
prompt = self.model_cls.get_generation_prompt(
audio=chunk,
stt_config=self.asr_config,
model_config=self.model_config,
language=language,
task_type=self.task_type,
request_prompt=request.prompt,
to_language=to_language,
)
prompts.append(prompt)
return prompts, duration
async def _create_speech_to_text(
self,
audio_data: bytes,
request: SpeechToTextRequest,
raw_request: Request,
response_class: type[T],
stream_generator_method: Callable[..., AsyncGenerator[str, None]],
) -> T | AsyncGenerator[str, None] | ErrorResponse:
"""Base method for speech-to-text operations like transcription and
translation."""
error_check_ret = await self._check_model(request)
if error_check_ret is not None:
return error_check_ret
# If the engine is dead, raise the engine's DEAD_ERROR.
# This is required for the streaming case, where we return a
# success status before we actually start generating text :).
if self.engine_client.errored:
raise self.engine_client.dead_error
if request.response_format not in ["text", "json"]:
return self.create_error_response(
"Currently only support response_format `text` or `json`"
)
request_id = f"{self.task_type}-{self._base_request_id(raw_request)}"
request_metadata = RequestResponseMetadata(request_id=request_id)
if raw_request:
raw_request.state.request_metadata = request_metadata
try:
lora_request = self._maybe_get_adapters(request)
prompts, duration_s = await self._preprocess_speech_to_text(
request=request,
audio_data=audio_data,
)
except ValueError as e:
logger.exception("Error in preprocessing prompt inputs")
return self.create_error_response(str(e))
list_result_generator: list[AsyncGenerator[RequestOutput, None]] | None = None
try:
# Unlike most decoder-only models, whisper generation length is not
# constrained by the size of the input audio, which is mapped to a
# fixed-size log-mel-spectogram.
default_max_tokens = self.model_config.max_model_len
sampling_params = request.to_sampling_params(
default_max_tokens, self.default_sampling_params
)
self._log_inputs(
request_id,
# It will not display special tokens like <|startoftranscript|>
request.prompt,
params=sampling_params,
lora_request=lora_request,
)
list_result_generator = [
self.engine_client.generate(
prompt,
sampling_params,
f"{request_id}_{i}",
lora_request=lora_request,
)
for i, prompt in enumerate(prompts)
]
except ValueError as e:
# TODO: Use a vllm-specific Validation Error
return self.create_error_response(str(e))
if request.stream:
return stream_generator_method(
request, list_result_generator, request_id, request_metadata, duration_s
)
# Non-streaming response.
try:
assert list_result_generator is not None
text = ""
for result_generator in list_result_generator:
async for op in result_generator:
text += op.outputs[0].text
if self.task_type == "transcribe":
# add usage in TranscriptionResponse.
usage = {
"type": "duration",
# rounded up as per openAI specs
"seconds": int(math.ceil(duration_s)),
}
final_response = cast(T, response_class(text=text, usage=usage))
else:
# no usage in response for translation task
final_response = cast(T, response_class(text=text)) # type: ignore[call-arg]
return final_response
except asyncio.CancelledError:
return self.create_error_response("Client disconnected")
except ValueError as e:
# TODO: Use a vllm-specific Validation Error
return self.create_error_response(str(e))
async def _speech_to_text_stream_generator(
self,
request: SpeechToTextRequest,
list_result_generator: list[AsyncGenerator[RequestOutput, None]],
request_id: str,
request_metadata: RequestResponseMetadata,
audio_duration_s: float,
chunk_object_type: Literal["translation.chunk", "transcription.chunk"],
response_stream_choice_class: type[TranscriptionResponseStreamChoice]
| type[TranslationResponseStreamChoice],
stream_response_class: type[TranscriptionStreamResponse]
| type[TranslationStreamResponse],
) -> AsyncGenerator[str, None]:
created_time = int(time.time())
model_name = request.model
completion_tokens = 0
num_prompt_tokens = 0
include_usage = self.enable_force_include_usage or request.stream_include_usage
include_continuous_usage = (
request.stream_continuous_usage_stats
if include_usage and request.stream_continuous_usage_stats
else False
)
try:
for result_generator in list_result_generator:
async for res in result_generator:
# On first result.
if res.prompt_token_ids is not None:
num_prompt_tokens = len(res.prompt_token_ids)
if audio_tokens := self.model_cls.get_num_audio_tokens(
audio_duration_s, self.asr_config, self.model_config
):
num_prompt_tokens += audio_tokens
# We need to do it here, because if there are exceptions in
# the result_generator, it needs to be sent as the FIRST
# response (by the try...catch).
# Just one output (n=1) supported.
assert len(res.outputs) == 1
output = res.outputs[0]
delta_message = DeltaMessage(content=output.text)
completion_tokens += len(output.token_ids)
if output.finish_reason is None:
# Still generating, send delta update.
choice_data = response_stream_choice_class(delta=delta_message)
else:
# Model is finished generating.
choice_data = response_stream_choice_class(
delta=delta_message,
finish_reason=output.finish_reason,
stop_reason=output.stop_reason,
)
chunk = stream_response_class(
id=request_id,
object=chunk_object_type,
created=created_time,
choices=[choice_data],
model=model_name,
)
# handle usage stats if requested & if continuous
if include_continuous_usage:
chunk.usage = UsageInfo(
prompt_tokens=num_prompt_tokens,
completion_tokens=completion_tokens,
total_tokens=num_prompt_tokens + completion_tokens,
)
data = chunk.model_dump_json(exclude_unset=True)
yield f"data: {data}\n\n"
# Once the final token is handled, if stream_options.include_usage
# is sent, send the usage.
if include_usage:
final_usage = UsageInfo(
prompt_tokens=num_prompt_tokens,
completion_tokens=completion_tokens,
total_tokens=num_prompt_tokens + completion_tokens,
)
final_usage_chunk = stream_response_class(
id=request_id,
object=chunk_object_type,
created=created_time,
choices=[],
model=model_name,
usage=final_usage,
)
final_usage_data = final_usage_chunk.model_dump_json(
exclude_unset=True, exclude_none=True
)
yield f"data: {final_usage_data}\n\n"
# report to FastAPI middleware aggregate usage across all choices
request_metadata.final_usage_info = UsageInfo(
prompt_tokens=num_prompt_tokens,
completion_tokens=completion_tokens,
total_tokens=num_prompt_tokens + completion_tokens,
)
except Exception as e:
# TODO: Use a vllm-specific Validation Error
logger.exception("Error in %s stream generator.", self.task_type)
data = self.create_streaming_error_response(str(e))
yield f"data: {data}\n\n"
# Send the final done message after all response.n are finished
yield "data: [DONE]\n\n"
def _split_audio(
self, audio_data: np.ndarray, sample_rate: int
) -> list[np.ndarray]:
chunk_size = sample_rate * self.asr_config.max_audio_clip_s
overlap_size = sample_rate * self.asr_config.overlap_chunk_second
chunks = []
i = 0
while i < audio_data.shape[-1]:
if i + chunk_size >= audio_data.shape[-1]:
# handle last chunk
chunks.append(audio_data[..., i:])
break
# Find the best split point in the overlap region
search_start = i + chunk_size - overlap_size
search_end = min(i + chunk_size, audio_data.shape[-1])
split_point = self._find_split_point(audio_data, search_start, search_end)
# Extract chunk up to the split point
chunks.append(audio_data[..., i:split_point])
i = split_point
return chunks
def _find_split_point(self, wav: np.ndarray, start_idx: int, end_idx: int) -> int:
"""Find the best point to split audio by
looking for silence or low amplitude.
Args:
wav: Audio tensor [1, T]
start_idx: Start index of search region
end_idx: End index of search region
Returns:
Index of best splitting point
"""
segment = wav[start_idx:end_idx]
# Calculate RMS energy in small windows
min_energy = math.inf
quietest_idx = 0
min_energy_window = self.asr_config.min_energy_split_window_size
assert min_energy_window is not None
for i in range(0, len(segment) - min_energy_window, min_energy_window):
window = segment[i : i + min_energy_window]
energy = (window**2).mean() ** 0.5
if energy < min_energy:
quietest_idx = i + start_idx
min_energy = energy
return quietest_idx