predict.py

"""
download the models to ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/65147644a518d12f04e32d6f3b26facc3f8dd46e5390956a9424a650c0ce22b9/tiny.pt -P ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/ed3a0b6b1c0edf879ad9b11b1af5a0e6ab5db9205f891f668f8b0e6c6326e34e/base.pt -P ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/9ecf779972d90ba49c06d968637d720dd632c55bbf19d441fb42bf17a411e794/small.pt -P ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/345ae4da62f9b3d59415adc60127b97c714f32e89e936602e85993674d08dcb1/medium.pt -P ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/e4b87e7e0bf463eb8e6956e646f1e277e901512310def2c24bf0e11bd3c28e9a/large-v1.pt  -P ./weights
wget https://openaipublic.azureedge.net/main/whisper/models/81f7c96c852ee8fc832187b0132e569d6c3065a3252ed18e56effd0b6a73e524/large-v2.pt  -P ./weights
"""

import io
import os
from typing import Optional, Any
import torch
import numpy as np
from cog import BasePredictor, Input, Path, BaseModel

import whisper
from whisper.model import Whisper, ModelDimensions
from whisper.tokenizer import LANGUAGES, TO_LANGUAGE_CODE
from whisper.utils import format_timestamp


class ModelOutput(BaseModel):
    detected_language: str
    transcription: str
    segments: Any
    translation: Optional[str]
    txt_file: Optional[Path]
    srt_file: Optional[Path]


class Predictor(BasePredictor):
    def setup(self):
        """Load the model into memory to make running multiple predictions efficient"""

        self.models = {}
        for model in ["tiny", "base", "small", "medium", "large-v1", "large-v2"]:
            with open(f"weights/{model}.pt", "rb") as fp:
                checkpoint = torch.load(fp, map_location="cpu")
                dims = ModelDimensions(**checkpoint["dims"])
                self.models[model] = Whisper(dims)
                self.models[model].load_state_dict(checkpoint["model_state_dict"])

    def predict(
        self,
        audio: Path = Input(description="Audio file"),
        model: str = Input(
            default="base",
            choices=["tiny", "base", "small", "medium", "large-v1", "large-v2"],
            description="Choose a Whisper model.",
        ),
        transcription: str = Input(
            choices=["plain text", "srt", "vtt"],
            default="plain text",
            description="Choose the format for the transcription",
        ),
        translate: bool = Input(
            default=False,
            description="Translate the text to English when set to True",
        ),
        language: str = Input(
            choices=sorted(LANGUAGES.keys())
            + sorted([k.title() for k in TO_LANGUAGE_CODE.keys()]),
            default=None,
            description="language spoken in the audio, specify None to perform language detection",
        ),
        temperature: float = Input(
            default=0,
            description="temperature to use for sampling",
        ),
        patience: float = Input(
            default=None,
            description="optional patience value to use in beam decoding, as in https://arxiv.org/abs/2204.05424, the default (1.0) is equivalent to conventional beam search",
        ),
        suppress_tokens: str = Input(
            default="-1",
            description="comma-separated list of token ids to suppress during sampling; '-1' will suppress most special characters except common punctuations",
        ),
        initial_prompt: str = Input(
            default=None,
            description="optional text to provide as a prompt for the first window.",
        ),
        condition_on_previous_text: bool = Input(
            default=True,
            description="if True, provide the previous output of the model 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",
        ),
        temperature_increment_on_fallback: float = Input(
            default=0.2,
            description="temperature to increase when falling back when the decoding fails to meet either of the thresholds below",
        ),
        compression_ratio_threshold: float = Input(
            default=2.4,
            description="if the gzip compression ratio is higher than this value, treat the decoding as failed",
        ),
        logprob_threshold: float = Input(
            default=-1.0,
            description="if the average log probability is lower than this value, treat the decoding as failed",
        ),
        no_speech_threshold: float = Input(
            default=0.6,
            description="if the probability of the <|nospeech|> token is higher than this value AND the decoding has failed due to `logprob_threshold`, consider the segment as silence",
        ),
    ) -> ModelOutput:

        """Run a single prediction on the model"""
        print(f"Transcribe with {model} model")
        model = self.models[model].to("cuda")

        if temperature_increment_on_fallback is not None:
            temperature = tuple(
                np.arange(temperature, 1.0 + 1e-6, temperature_increment_on_fallback)
            )
        else:
            temperature = [temperature]

        args = {
            "language": language,
            "patience": patience,
            "suppress_tokens": suppress_tokens,
            "initial_prompt": initial_prompt,
            "condition_on_previous_text": condition_on_previous_text,
            "compression_ratio_threshold": compression_ratio_threshold,
            "logprob_threshold": logprob_threshold,
            "no_speech_threshold": no_speech_threshold,
        }

        result = model.transcribe(str(audio), temperature=temperature, **args)

        if transcription == "plain text":
            transcription = result["text"]
        elif transcription == "srt":
            transcription = write_srt(result["segments"])
        else:
            transcription = write_vtt(result["segments"])

        if translate:
            translation = model.transcribe(
                str(audio), task="translate", temperature=temperature, **args
            )

        return ModelOutput(
            segments=result["segments"],
            detected_language=LANGUAGES[result["language"]],
            transcription=transcription,
            translation=translation["text"] if translate else None,
        )


def write_vtt(transcript):
    result = ""
    for segment in transcript:
        result += f"{format_timestamp(segment['start'])} --> {format_timestamp(segment['end'])}\n"
        result += f"{segment['text'].strip().replace('-->', '->')}\n"
        result += "\n"
    return result


def write_srt(transcript):
    result = ""
    for i, segment in enumerate(transcript, start=1):
        result += f"{i}\n"
        result += f"{format_timestamp(segment['start'], always_include_hours=True, decimal_marker=',')} --> "
        result += f"{format_timestamp(segment['end'], always_include_hours=True, decimal_marker=',')}\n"
        result += f"{segment['text'].strip().replace('-->', '->')}\n"
        result += "\n"
    return result