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Generate Video Subtitles

Updated May 15, 2025 ·

You can generate English subtitles (e.g., .srt files) from MP4 videos using automatic speech recognition (ASR) tools.

OpenAI Whisper (Best Accuracy)​

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Of all the options, this is the one that I used for majority of my videos.

Whisper is an open-source ASR model by OpenAI, known for its accuracy and support for many languages.

  1. Make sure Python 3.8+ and pip are available:

    python3 --version
    pip3 --version

    If not yet installed:

    sudo apt update
    sudo apt install -y python3 python3-pip

  2. Install Whisper and dependencies:

    pip install openai-whisper
    sudo apt install ffmpeg

  3. Verify:

    pip show openai-whisper

    Sample output:

    Name: openai-whisper
    Version: 20240930
    Summary: Robust Speech Recognition via Large-Scale Weak Supervision
    Home-page: https://github.com/openai/whisper
    Author: OpenAI
    Author-email:
    License: MIT
    Location: /home/username/.local/lib/python3.10/site-packages
    Requires: more-itertools, numba, numpy, tiktoken, torch, tqdm, triton

  4. Generate subtitles:

    whisper your_video.mp4 --language English --task transcribe --output_format srt

  5. It will create your_video.srt in the same folder.

Note: It uses your CPU or GPU. Can be slow on large files without a GPU.

(Optional) Transcribe All MP4s in a Folder​

If you have multiple videos that you want to transcribe, you can use a script:

for f in *.mp4; do
  whisper "$f" --language English --task transcribe --output_format srt
done

To process MP4 files in the current directory and all nested directories (recursively):

find . -type f -name "*.mp4" | while read -r f; do
  whisper "$f" --language English --task transcribe --output_format srt
done

SubtitleEdit (GUI, Windows)​

Subtitle Edit is a Windows app with built-in speech recognition using Whisper or Google APIs.

  1. Download Subtitle Edit: https://www.nikse.dk/subtitleedit/
  2. Open your MP4 video in the app.
  3. Go to Video > Audio to text (Whisper) or Generate Subtitles via Google.

YouTube (Hacky but works)​

If the video is not sensitive/private, upload it as unlisted to YouTube.

  1. Upload video as unlisted/private.
  2. Wait for auto-captions to generate.
  3. Download captions via YouTube Studio or use 3rd-party tools like DownSub.

Online Tools​

There are websites that offer auto-captioning:

These often require a free account or have limits unless you subscribe.

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