app/faster_whisper/utils.py

# MIT License
#
# Copyright (c) 2022 Ahmet Oner & Besim Alibegovic
# Portions Copyright (c) 2024 Team Audio
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import json
import os
from typing import TextIO

from faster_whisper.utils import format_timestamp


class ResultWriter:
    extension: str

    def __init__(self, output_dir: str):
        self.output_dir = output_dir

    def __call__(self, result: dict, audio_path: str):
        audio_basename = os.path.basename(audio_path)
        output_path = os.path.join(self.output_dir, audio_basename + "." + self.extension)

        with open(output_path, "w", encoding="utf-8") as f:
            self.write_result(result, file=f)

    def write_result(self, result: dict, file: TextIO):
        raise NotImplementedError


class WriteTXT(ResultWriter):
    extension: str = "txt"

    def write_result(self, result: dict, file: TextIO):
        for segment in result["segments"]:
            print(segment['text'].strip(), file=file, flush=True)


class WriteVTT(ResultWriter):
    extension: str = "vtt"

    def write_result(self, result: dict, file: TextIO):
        print("WEBVTT\n", file=file)
        for segment in result["segments"]:
            print(
                f"{format_timestamp(segment['start'])} --> {format_timestamp(segment['end'])}\n"
                f"{segment['text'].strip().replace('-->', '->')}\n",
                file=file,
                flush=True,
            )


class WriteSRT(ResultWriter):
    extension: str = "srt"

    def write_result(self, result: dict, file: TextIO):
        for i, segment in enumerate(result["segments"], start=1):
            # write srt lines
            print(
                f"{i}\n"
                f"{format_timestamp(segment['start'], always_include_hours=True, decimal_marker=',')} --> "
                f"{format_timestamp(segment['end'], always_include_hours=True, decimal_marker=',')}\n"
                f"{segment['text'].strip().replace('-->', '->')}\n",
                file=file,
                flush=True,
            )


class WriteTSV(ResultWriter):
    """
    Write a transcript to a file in TSV (tab-separated values) format containing lines like:
    <start time in integer milliseconds>\t<end time in integer milliseconds>\t<transcript text>

    Using integer milliseconds as start and end times means there's no chance of interference from
    an environment setting a language encoding that causes the decimal in a floating point number
    to appear as a comma; also is faster and more efficient to parse & store, e.g., in C++.
    """
    extension: str = "tsv"

    def write_result(self, result: dict, file: TextIO):
        print("start", "end", "text", sep="\t", file=file)
        for segment in result["segments"]:
            print(round(1000 * segment['start']), file=file, end="\t")
            print(round(1000 * segment['end']), file=file, end="\t")
            print(segment['text'].strip().replace("\t", " "), file=file, flush=True)


class WriteJSON(ResultWriter):
    extension: str = "json"

    def write_result(self, result: dict, file: TextIO):
        json.dump(result, file)