core.py

import os
from io import StringIO
from threading import Lock
from typing import BinaryIO, Union

import torch
import whisper
from whisper.utils import ResultWriter, WriteJSON, WriteSRT, WriteTSV, WriteTXT, WriteVTT

model_name = os.getenv("ASR_MODEL", "base")
model_path = os.getenv("ASR_MODEL_PATH", os.path.join(os.path.expanduser("~"), ".cache", "whisper"))

if torch.cuda.is_available():
    model = whisper.load_model(model_name, download_root=model_path).cuda()
else:
    model = whisper.load_model(model_name, download_root=model_path)
model_lock = Lock()


def transcribe(
    audio,
    task: Union[str, None],
    language: Union[str, None],
    initial_prompt: Union[str, None],
    vad_filter: Union[bool, None],
    word_timestamps: Union[bool, None],
    output,
):
    options_dict = {"task": task}
    if language:
        options_dict["language"] = language
    if initial_prompt:
        options_dict["initial_prompt"] = initial_prompt
    if word_timestamps:
        options_dict["word_timestamps"] = word_timestamps
    with model_lock:
        result = model.transcribe(audio, **options_dict)

    output_file = StringIO()
    write_result(result, output_file, output)
    output_file.seek(0)

    return output_file


def language_detection(audio):
    # load audio and pad/trim it to fit 30 seconds
    audio = whisper.pad_or_trim(audio)

    # make log-Mel spectrogram and move to the same device as the model
    mel = whisper.log_mel_spectrogram(audio, model.dims.n_mels).to(model.device)

    # detect the spoken language
    with model_lock:
        _, probs = model.detect_language(mel)
    detected_lang_code = max(probs, key=probs.get)

    return detected_lang_code


def write_result(result: dict, file: BinaryIO, output: Union[str, None]):
    options = {"max_line_width": 1000, "max_line_count": 10, "highlight_words": False}
    if output == "srt":
        WriteSRT(ResultWriter).write_result(result, file=file, options=options)
    elif output == "vtt":
        WriteVTT(ResultWriter).write_result(result, file=file, options=options)
    elif output == "tsv":
        WriteTSV(ResultWriter).write_result(result, file=file, options=options)
    elif output == "json":
        WriteJSON(ResultWriter).write_result(result, file=file, options=options)
    elif output == "txt":
        WriteTXT(ResultWriter).write_result(result, file=file, options=options)
    else:
        return "Please select an output method!"