[Frontend] add 'verbose_json' and 'timestamp' feature on Whisper Transcription/Translation (#24209)

Signed-off-by: sangbumlikeagod <oironese@naver.com>
Signed-off-by: sangbumlikeagod <98077576+sangbumlikeagod@users.noreply.github.com>

docs/serving/openai_compatible_server.md

@@ -456,6 +456,7 @@ For `verbose_json` response format:
       ]
     }
     ```
+Currently “verbose_json” response format doesn’t support avg_logprob, compression_ratio, no_speech_prob.
 
 #### Extra Parameters
 

tests/entrypoints/openai/test_transcription_validation_whisper.py

@@ -235,3 +235,16 @@ async def test_audio_prompt(mary_had_lamb, whisper_client):
     )
     out_prompt = json.loads(transcription_wprompt)["text"]
     assert prefix in out_prompt
+
+
+@pytest.mark.asyncio
+async def test_audio_with_timestamp(mary_had_lamb, whisper_client):
+    transcription = await whisper_client.audio.transcriptions.create(
+        model=MODEL_NAME,
+        file=mary_had_lamb,
+        language="en",
+        response_format="verbose_json",
+        temperature=0.0,
+    )
+    assert transcription.segments is not None
+    assert len(transcription.segments) > 0

vllm/entrypoints/openai/api_server.py

@@ -68,9 +68,9 @@ from vllm.entrypoints.openai.protocol import (
     TokenizeRequest,
     TokenizeResponse,
     TranscriptionRequest,
-    TranscriptionResponse,
+    TranscriptionResponseVariant,
     TranslationRequest,
-    TranslationResponse,
+    TranslationResponseVariant,
 )
 from vllm.entrypoints.openai.serving_chat import OpenAIServingChat
 from vllm.entrypoints.openai.serving_completion import OpenAIServingCompletion
@@ -809,7 +809,7 @@ async def create_transcriptions(
             content=generator.model_dump(), status_code=generator.error.code
         )
 
-    elif isinstance(generator, TranscriptionResponse):
+    elif isinstance(generator, TranscriptionResponseVariant):
         return JSONResponse(content=generator.model_dump())
 
     return StreamingResponse(content=generator, media_type="text/event-stream")
@@ -848,7 +848,7 @@ async def create_translations(
             content=generator.model_dump(), status_code=generator.error.code
         )
 
-    elif isinstance(generator, TranslationResponse):
+    elif isinstance(generator, TranslationResponseVariant):
         return JSONResponse(content=generator.model_dump())
 
     return StreamingResponse(content=generator, media_type="text/event-stream")

vllm/entrypoints/openai/protocol.py

@@ -2126,13 +2126,13 @@ class TranscriptionSegment(OpenAIBaseModel):
     id: int
     """Unique identifier of the segment."""
 
-    avg_logprob: float
+    avg_logprob: float | None = None
     """Average logprob of the segment.
 
     If the value is lower than -1, consider the logprobs failed.
     """
 
-    compression_ratio: float
+    compression_ratio: float | None = None
     """Compression ratio of the segment.
 
     If the value is greater than 2.4, consider the compression failed.
@@ -2141,7 +2141,7 @@ class TranscriptionSegment(OpenAIBaseModel):
     end: float
     """End time of the segment in seconds."""
 
-    no_speech_prob: float
+    no_speech_prob: float | None = None
     """Probability of no speech in the segment.
 
     If the value is higher than 1.0 and the `avg_logprob` is below -1, consider
@@ -2181,6 +2181,11 @@ class TranscriptionResponseVerbose(OpenAIBaseModel):
     """Extracted words and their corresponding timestamps."""
 
 
+TranscriptionResponseVariant: TypeAlias = (
+    TranscriptionResponse | TranscriptionResponseVerbose
+)
+
+
 class TranslationResponseStreamChoice(OpenAIBaseModel):
     delta: DeltaMessage
     finish_reason: str | None = None
@@ -2325,13 +2330,13 @@ class TranslationSegment(OpenAIBaseModel):
     id: int
     """Unique identifier of the segment."""
 
-    avg_logprob: float
+    avg_logprob: float | None = None
     """Average logprob of the segment.
 
     If the value is lower than -1, consider the logprobs failed.
     """
 
-    compression_ratio: float
+    compression_ratio: float | None = None
     """Compression ratio of the segment.
 
     If the value is greater than 2.4, consider the compression failed.
@@ -2340,7 +2345,7 @@ class TranslationSegment(OpenAIBaseModel):
     end: float
     """End time of the segment in seconds."""
 
-    no_speech_prob: float
+    no_speech_prob: float | None = None
     """Probability of no speech in the segment.
 
     If the value is higher than 1.0 and the `avg_logprob` is below -1, consider
@@ -2380,6 +2385,9 @@ class TranslationResponseVerbose(OpenAIBaseModel):
     """Extracted words and their corresponding timestamps."""
 
 
+TranslationResponseVariant: TypeAlias = TranslationResponse | TranslationResponseVerbose
+
+
 ####### Tokens IN <> Tokens OUT #######
 class GenerateRequest(BaseModel):
     request_id: str = Field(

vllm/entrypoints/openai/serving_transcription.py

@@ -12,10 +12,12 @@ from vllm.entrypoints.openai.protocol import (
     TranscriptionRequest,
     TranscriptionResponse,
     TranscriptionResponseStreamChoice,
+    TranscriptionResponseVerbose,
     TranscriptionStreamResponse,
     TranslationRequest,
     TranslationResponse,
     TranslationResponseStreamChoice,
+    TranslationResponseVerbose,
     TranslationStreamResponse,
 )
 from vllm.entrypoints.openai.serving_models import OpenAIServingModels
@@ -51,7 +53,12 @@ class OpenAIServingTranscription(OpenAISpeechToText):
 
     async def create_transcription(
         self, audio_data: bytes, request: TranscriptionRequest, raw_request: Request
-    ) -> TranscriptionResponse | AsyncGenerator[str, None] | ErrorResponse:
+    ) -> (
+        TranscriptionResponse
+        | TranscriptionResponseVerbose
+        | AsyncGenerator[str, None]
+        | ErrorResponse
+    ):
         """Transcription API similar to OpenAI's API.
 
         See https://platform.openai.com/docs/api-reference/audio/createTranscription
@@ -61,7 +68,11 @@ class OpenAIServingTranscription(OpenAISpeechToText):
             audio_data=audio_data,
             request=request,
             raw_request=raw_request,
-            response_class=TranscriptionResponse,
+            response_class=(
+                TranscriptionResponseVerbose
+                if request.response_format == "verbose_json"
+                else TranscriptionResponse
+            ),
             stream_generator_method=self.transcription_stream_generator,
         )
 
@@ -112,7 +123,12 @@ class OpenAIServingTranslation(OpenAISpeechToText):
 
     async def create_translation(
         self, audio_data: bytes, request: TranslationRequest, raw_request: Request
-    ) -> TranslationResponse | AsyncGenerator[str, None] | ErrorResponse:
+    ) -> (
+        TranslationResponse
+        | TranslationResponseVerbose
+        | AsyncGenerator[str, None]
+        | ErrorResponse
+    ):
         """Translation API similar to OpenAI's API.
 
         See https://platform.openai.com/docs/api-reference/audio/createTranslation
@@ -122,7 +138,11 @@ class OpenAIServingTranslation(OpenAISpeechToText):
             audio_data=audio_data,
             request=request,
             raw_request=raw_request,
-            response_class=TranslationResponse,
+            response_class=(
+                TranslationResponseVerbose
+                if request.response_format == "verbose_json"
+                else TranslationResponse
+            ),
             stream_generator_method=self.translation_stream_generator,
         )
 

vllm/entrypoints/openai/speech_to_text.py

@@ -10,6 +10,7 @@ from typing import Literal, TypeAlias, TypeVar, cast
 
 import numpy as np
 from fastapi import Request
+from transformers import PreTrainedTokenizerBase
 
 import vllm.envs as envs
 from vllm.engine.protocol import EngineClient
@@ -20,9 +21,13 @@ from vllm.entrypoints.openai.protocol import (
     RequestResponseMetadata,
     TranscriptionResponse,
     TranscriptionResponseStreamChoice,
+    TranscriptionResponseVerbose,
+    TranscriptionSegment,
     TranscriptionStreamResponse,
     TranslationResponse,
     TranslationResponseStreamChoice,
+    TranslationResponseVerbose,
+    TranslationSegment,
     TranslationStreamResponse,
     UsageInfo,
 )
@@ -32,6 +37,7 @@ 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.transformers_utils.tokenizer import get_tokenizer
 from vllm.utils.import_utils import PlaceholderModule
 
 try:
@@ -40,7 +46,20 @@ except ImportError:
     librosa = PlaceholderModule("librosa")  # type: ignore[assignment]
 
 SpeechToTextResponse: TypeAlias = TranscriptionResponse | TranslationResponse
+SpeechToTextResponseVerbose: TypeAlias = (
+    TranscriptionResponseVerbose | TranslationResponseVerbose
+)
+SpeechToTextSegment: TypeAlias = TranscriptionSegment | TranslationSegment
 T = TypeVar("T", bound=SpeechToTextResponse)
+V = TypeVar("V", bound=SpeechToTextResponseVerbose)
+S = TypeVar("S", bound=SpeechToTextSegment)
+
+ResponseType: TypeAlias = (
+    TranscriptionResponse
+    | TranslationResponse
+    | TranscriptionResponseVerbose
+    | TranslationResponseVerbose
+)
 
 logger = init_logger(__name__)
 
@@ -78,6 +97,14 @@ class OpenAISpeechToText(OpenAIServing):
         self.enable_force_include_usage = enable_force_include_usage
 
         self.max_audio_filesize_mb = envs.VLLM_MAX_AUDIO_CLIP_FILESIZE_MB
+        if self.model_cls.supports_segment_timestamp:
+            self.tokenizer = cast(
+                PreTrainedTokenizerBase,
+                get_tokenizer(
+                    tokenizer_name=self.model_config.tokenizer,
+                    tokenizer_mode=self.model_config.tokenizer_mode,
+                ),
+            )
 
         if self.default_sampling_params:
             logger.info(
@@ -133,17 +160,87 @@ class OpenAISpeechToText(OpenAIServing):
                 request_prompt=request.prompt,
                 to_language=to_language,
             )
+            if request.response_format == "verbose_json":
+                if not isinstance(prompt, dict):
+                    raise ValueError(f"Expected prompt to be a dict,got {type(prompt)}")
+                prompt_dict = cast(dict, prompt)
+                decoder_prompt = prompt.get("decoder_prompt")
+                if not isinstance(decoder_prompt, str):
+                    raise ValueError(
+                        f"Expected decoder_prompt to bestr, got {type(decoder_prompt)}"
+                    )
+                prompt_dict["decoder_prompt"] = decoder_prompt.replace(
+                    "<|notimestamps|>", "<|0.00|>"
+                )
             prompts.append(prompt)
         return prompts, duration
 
+    def _get_verbose_segments(
+        self,
+        tokens: tuple,
+        request: SpeechToTextRequest,
+        segment_class: type[SpeechToTextSegment],
+        start_time: float = 0,
+    ) -> list[SpeechToTextSegment]:
+        """
+        Convert tokens to verbose segments.
+
+        This method expects the model to produce
+        timestamps as tokens (similar to Whisper).
+        If the tokens do not include timestamp information,
+        the segments may not be generated correctly.
+
+        Note: Fields like avg_logprob, compression_ratio,
+        and no_speech_prob are not supported
+        in this implementation and will be None. See docs for details.
+        """
+        BASE_OFFSET = 0.02
+        init_token = self.tokenizer.encode("<|0.00|>", add_special_tokens=False)[0]
+        if tokens[-1] == self.tokenizer.eos_token_id:
+            tokens = tokens[:-1]
+
+        tokens_with_start = (init_token,) + tokens
+        segments: list[SpeechToTextSegment] = []
+        last_timestamp_start = 0
+
+        if tokens_with_start[-2] < init_token and tokens_with_start[-1] >= init_token:
+            tokens_with_start = tokens_with_start + (tokens_with_start[-1],)
+        for idx, token in enumerate(tokens_with_start):
+            # Timestamp tokens (e.g., <|0.00|>) are assumed to be sorted.
+            # If the ordering is violated, this slicing may produce incorrect results.
+            if (
+                token >= init_token
+                and idx != 0
+                and tokens_with_start[idx - 1] >= init_token
+            ):
+                sliced_timestamp_tokens = tokens_with_start[last_timestamp_start:idx]
+                start_timestamp = sliced_timestamp_tokens[0] - init_token
+                end_timestamp = sliced_timestamp_tokens[-1] - init_token
+
+                casting_segment = cast(
+                    SpeechToTextSegment,
+                    segment_class(
+                        id=len(segments),
+                        seek=start_time,
+                        start=start_time + BASE_OFFSET * start_timestamp,
+                        end=start_time + BASE_OFFSET * end_timestamp,
+                        temperature=request.temperature,
+                        text=self.tokenizer.decode(sliced_timestamp_tokens[1:-1]),
+                        tokens=sliced_timestamp_tokens[1:-1],
+                    ),
+                )
+                segments.append(casting_segment)
+                last_timestamp_start = idx
+        return segments
+
     async def _create_speech_to_text(
         self,
         audio_data: bytes,
         request: SpeechToTextRequest,
         raw_request: Request,
-        response_class: type[T],
+        response_class: type[T | V],
         stream_generator_method: Callable[..., AsyncGenerator[str, None]],
-    ) -> T | AsyncGenerator[str, None] | ErrorResponse:
+    ) -> T | V | AsyncGenerator[str, None] | ErrorResponse:
         """Base method for speech-to-text operations like transcription and
         translation."""
         error_check_ret = await self._check_model(request)
@@ -156,11 +253,24 @@ class OpenAISpeechToText(OpenAIServing):
         if self.engine_client.errored:
             raise self.engine_client.dead_error
 
-        if request.response_format not in ["text", "json"]:
+        if request.response_format not in ["text", "json", "verbose_json"]:
             return self.create_error_response(
-                "Currently only support response_format `text` or `json`"
+                ("Currently only support response_format")
+                + ("`text`, `json` or `verbose_json`")
             )
 
+        if (
+            request.response_format == "verbose_json"
+            and not self.model_cls.supports_segment_timestamp
+        ):
+            return self.create_error_response(
+                f"Currently do not support verbose_json for {request.model}"
+            )
+
+        if request.response_format == "verbose_json" and request.stream:
+            return self.create_error_response(
+                "verbose_json format doesn't support streaming case"
+            )
         request_id = f"{self.task_type}-{self._base_request_id(raw_request)}"
 
         request_metadata = RequestResponseMetadata(request_id=request_id)
@@ -215,25 +325,69 @@ class OpenAISpeechToText(OpenAIServing):
                 request, list_result_generator, request_id, request_metadata, duration_s
             )
         # Non-streaming response.
+        total_segments = []
+        text_parts = []
         try:
             assert list_result_generator is not None
+            segments_types: dict[str, type[SpeechToTextSegment]] = {
+                "transcribe": TranscriptionSegment,
+                "translate": TranslationSegment,
+            }
+            segment_class: type[SpeechToTextSegment] = segments_types[self.task_type]
             text = ""
-            for result_generator in list_result_generator:
+            for idx, result_generator in enumerate(list_result_generator):
                 async for op in result_generator:
-                    text += op.outputs[0].text
+                    if request.response_format == "verbose_json":
+                        segments: list[SpeechToTextSegment] = (
+                            self._get_verbose_segments(
+                                tokens=tuple(op.outputs[0].token_ids),
+                                segment_class=segment_class,
+                                request=request,
+                                start_time=idx * self.asr_config.max_audio_clip_s,
+                            )
+                        )
 
+                        total_segments.extend(segments)
+                        text_parts.extend([seg.text for seg in segments])
+                    else:
+                        text_parts.append(op.outputs[0].text)
+            text = "".join(text_parts)
             if self.task_type == "transcribe":
+                final_response: ResponseType
                 # 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))
+                if request.response_format != "verbose_json":
+                    final_response = cast(
+                        T, TranscriptionResponse(text=text, usage=usage)
+                    )
+                else:
+                    final_response = cast(
+                        V,
+                        TranscriptionResponseVerbose(
+                            text=text,
+                            language=request.language,
+                            duration=str(duration_s),
+                            segments=total_segments,
+                        ),
+                    )
             else:
                 # no usage in response for translation task
-                final_response = cast(T, response_class(text=text))  # type: ignore[call-arg]
-
+                if request.response_format != "verbose_json":
+                    final_response = cast(T, TranslationResponse(text=text))
+                else:
+                    final_response = cast(
+                        V,
+                        TranslationResponseVerbose(
+                            text=text,
+                            language=request.language,
+                            duration=str(duration_s),
+                            segments=total_segments,
+                        ),
+                    )
             return final_response
         except asyncio.CancelledError:
             return self.create_error_response("Client disconnected")

vllm/model_executor/models/interfaces.py

@@ -837,6 +837,10 @@ class SupportsTranscription(Protocol):
     Transcription models can opt out of text generation by setting this to
     `True`.
     """
+    supports_segment_timestamp: ClassVar[bool] = False
+    """
+    Enables the segment timestamp option for supported models by setting this to `True`.
+    """
 
     def __init_subclass__(cls, **kwargs):
         super().__init_subclass__(**kwargs)

vllm/model_executor/models/whisper.py

@@ -791,6 +791,7 @@ class WhisperForConditionalGeneration(
 
     # Whisper only supports audio-conditioned generation.
     supports_transcription_only = True
+    supports_segment_timestamp = True
     supported_languages = ISO639_1_SUPPORTED_LANGS
 
     @classmethod