YouTube subtitle downloader

Baixar Legendas YouTube is a Python command-line script with an optional desktop GUI that downloads the .srt subtitles of a single video, a whole YouTube channel, a playlist or a pasted list of URLs in one run, built on yt-dlp and pywebview, with no YouTube API key required.

YouTube has no built-in way to grab every subtitle from a channel or playlist at once, and downloading them video by video is slow. This tool hands the URLs to yt-dlp, skips the video and audio, and saves only the captions.

YouTube subtitle downloader · download YouTube captions · bulk SRT download · channel transcripts · playlist subtitles · yt-dlp subtitles · auto-generated captions

Features

• Video, channel or playlist. Pass any mix of URLs. yt-dlp expands channels (.../videos) and playlists to every video.
• SRT output. Subtitles are converted to .srt with ffmpeg.
• Language choice. Defaults to pt,pt-BR,en; pass any comma-separated list.
• Auto-generated captions. The optional --auto flag includes YouTube automatic captions.
• Keeps going on errors. A video with no subtitle in the requested languages is skipped and the rest continue.
• Subtitles only. It never downloads video or audio.
• Optional GUI. A small pywebview window with a URL box, language field, folder picker, auto-caption checkbox and a live log.

Tech stack

Technology	Version	Used for
Python	3.9+	Runtime (the code uses list[str] type hints, which need 3.9+)
yt-dlp	unpinned in requirements.txt	Fetching and downloading subtitles
pywebview	unpinned in requirements.txt	Native window for the optional GUI (gui.py)
pythonnet	unpinned; installed only when sys_platform == "win32"	pywebview backend on Windows
ffmpeg	external, not a Python package	Converts subtitles to .srt

Getting started

Requirements: Python 3.9 or newer, and ffmpeg on your PATH.

git clone https://github.com/WednyFernandes/baixar-legendas-youtube.git
cd baixar-legendas-youtube
pip install -r requirements.txt

Usage

Command line

python baixar_legendas_canal.py https://www.youtube.com/@channel/videos

It accepts a video, a channel or a playlist, alone or combined:

python baixar_legendas_canal.py https://www.youtube.com/watch?v=XXXX
python baixar_legendas_canal.py URL1 URL2 URL3
python baixar_legendas_canal.py URL --idiomas en,es --saida subs --auto

Files are saved as <output folder>/<video title>.srt.

Argument	Default	Description
urls	required	One or more URLs: video, channel (.../videos) or playlist
--idiomas	pt,pt-BR,en	Subtitle languages, comma-separated
--saida	legendas	Output folder for the .srt files
--auto	off	Include auto-generated subtitles when no manual one exists

Desktop GUI

python gui.py

Paste one URL per line (video, channel, playlist or a mixed list), set the languages and output folder, tick the auto-caption box if needed, and start. The log shows a Baixado: <file> (downloaded) line per subtitle and Concluido. (done) at the end.

How it works

The script calls yt_dlp directly and passes the list of URLs to ydl.download(urls). yt-dlp detects whether each URL is a video, a channel or a playlist and expands it, so all cases share one code path. It runs with skip_download=True and writesubtitles=True (plus writeautomaticsub when --auto is on), and converts the result to .srt through the FFmpegSubtitlesConvertor post-processor. ignoreerrors=True makes it skip videos without a matching subtitle. The GUI (gui.py) calls the same functions (baixar_legendas, parse_urls) on a background thread and streams the log to the window.

Project structure

baixar_legendas_canal.py   # CLI: parses arguments and runs the download via yt-dlp
gui.py                     # pywebview window that calls the same functions as the CLI
gui.html                   # GUI markup (HTML + Tailwind via CDN)
requirements.txt           # Python dependencies

FAQ

Do I need a YouTube API key? No. yt-dlp reads the public subtitle tracks directly.

Can I download the subtitles of an entire YouTube channel? Yes. Pass the channel videos URL, for example https://www.youtube.com/@channel/videos, and every video with a subtitle in your chosen languages is saved.

Why is a video missing from the output folder? It had no subtitle in the requested languages. Add more languages with --idiomas, or use --auto to include auto-generated captions.

Does it download the video too? No. It only saves the subtitle files.