How to Create Subtitle-Files (srt) with WhisperAI

For my tutorial videos I want to provide high-quality subtitles. But I did not want to write them myself as this is a tedious task.

Luckily there is WhisperAI that can help me, or so it promises 😂 Time to give it a shot for my current project.

Install WhisperAI

I followed their installation guide on their GitHub-Repository side. It is a Python tool so the first step I did was setting up a virtual-environment (my current installed version is 3.9.6 on macOS. Here are all the commands I ran:

## I installed python with brew as far as I remember ;-)
## Initialize and activate the virtualenv
python3 -m venv venv
source venv/bin/activate

## Install latest WhisperAI from Github
pip install git+https://github.com/openai/whisper.git

## Install ffmpeg
brew install ffmpeg

Create Util-Script for Easier Handling

With that set I created a little script based on this Gist. It was for an older version of WhisperAI so I had to implement some changes. Save it as createSrt.py or whatever name you like 😋:

import sys

import whisper
from whisper.utils import get_writer


def run(input_path: str, output_name: str = "", output_directory: str = "./") -> None:
    model = whisper.load_model("medium")
    result = model.transcribe(input_path)

    writer = get_writer("srt", str(output_directory))
    writer(result, output_name)

def main() -> None:
    if len(sys.argv) != 4:
        print(
            "Error: Invalid number of arguments.\n"
            "Usage: python createSrt.py <input-path> <output-name> <output-directory>\n"
            "Example: python createSrt.py transcribed.srt ./transcribed"
        )
        sys.exit(1)

    run(input_path=sys.argv[1], output_name=sys.argv[2], output_directory=sys.argv[3])


if __name__ == "__main__":
    main()

Usage of Util-Script

You can call it like this and it can handle .wav and also .mp4. So you do not even have to export your videos in another format to use it:

python createSrt.py <path to your mp4/wav file> <name of the srt file> <path to where to save the srt file>

Adjustments

If you want to use another model instead of medium you have to change the following line and replace medium with a model documented here:

model = whisper.load_model("medium")

If you want to change the output format you can use one of the following instead of srt: vtt, tsv, json, txt. Change it in the following line:

writer = get_writer("srt", str(output_directory))

Happy transcribing 🦄