slidecast

🎙️ slidecast

Turn any topic into a polished HTML slide deck — then narrate it into a slide-synced video.
A Claude Code plugin powered by ElevenLabs text-to-speech.

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You:    make a 10-slide presentation about our Q3 roadmap, dark theme
Claude: …writes roadmap.html  (a clean, self-contained deck)

You:    now turn it into a narrated video with a calm female voice
Claude: …writes narration.json, picks a voice, renders + speaks each slide → roadmap.mp4

slidecast adds two skills to Claude Code:

Skill	What it does
create-presentation	Generates a branded, self-contained HTML deck — 16:9, keyboard-navigable, themeable accent colour, optional dimmed logo watermark.
narrate-to-video	Renders each slide headless, generates per-slide narration with ElevenLabs, and stitches a slide-synced MP4 with ffmpeg.

Both are model-invoked — just describe what you want. No commands to memorize.

Bring your own ElevenLabs key. slidecast never bundles credentials; speech runs on your account, billed to your quota.

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Requirements

Tool	Why	Install
ELEVENLABS_API_KEY	text-to-speech (your account)	elevenlabs.io → Profile → API Keys
ffmpeg + ffprobe	audio/video assembly	brew install ffmpeg · apt install ffmpeg
Google Chrome / Chromium	headless slide rendering	any recent build (auto-detected, or set CHROME_BIN)
python3	helper scripts (stdlib only — no pip installs)	preinstalled on macOS/Linux

Only the create-presentation skill works without ElevenLabs; you just won't be able to render video.

Install

/plugin marketplace add alinaqi/slidecast
/plugin install slidecast@slidecast

Then make your key available to the session (or put it in your shell profile):

! export ELEVENLABS_API_KEY=sk_your_key_here

Usage

Make a deck

> Create a 12-slide deck introducing our API, accent colour #6366f1, brand "Acme".

You get a single acme-api.html you can open in any browser. Arrow keys navigate; #3 jumps to slide 3.

Narrate it into a video

> Turn acme-api.html into a narrated video. Use a warm British female voice.

Claude drafts narration.json (one line per slide), picks a voice, and runs the build. The acme-api.mp4 lands next to the deck — each slide held for exactly the length of its narration.

Iterate cheaply. The build is idempotent: edit one slide's narration, delete that clip, re-run — only the changed slide is regenerated.

How it works

1. The deck is one self-contained HTML file with a tiny slide engine: #N jumps to slide N · ?render=1 hides the nav chrome (for clean frames) · arrow keys navigate.
2. narration.json maps each slide to spoken text:

   { "voice_id": "<id>", "model": "eleven_multilingual_v2",
     "segments": [ { "slide": 1, "text": "..." }, { "slide": 2, "text": "..." } ] }
   

3. build_video.sh calls ElevenLabs per segment, screenshots each slide via headless Chrome, builds a per-slide ffmpeg clip held for the audio's duration (plus a short tail), and concatenates them into the final MP4.

Nothing is hard-coded — swap the voice, edit the text, rebrand the template, and re-run.

Choosing a voice

# your account voices
python3 scripts/list_voices.py
# the public shared library, filtered
python3 scripts/list_voices.py --shared --gender female --language en

Put the chosen voice_id in narration.json. Models: eleven_multilingual_v2 (accents / non-English), eleven_turbo_v2_5 (fast & cheap), eleven_v3 (most expressive).

Tuning (environment variables)

Var	Default	Effect
SLIDECAST_TAIL	0.6	seconds of silence held after each line
SLIDECAST_WIDTH / SLIDECAST_HEIGHT	1920 / 1080	output resolution
SLIDECAST_FORCE	0	1 = regenerate all audio + renders
SLIDECAST_STABILITY / SLIDECAST_SIMILARITY / SLIDECAST_STYLE	0.5 / 0.75 / 0.0	ElevenLabs voice settings
CHROME_BIN	auto	explicit Chrome/Chromium path

Local development

git clone https://github.com/alinaqi/slidecast
claude --plugin-dir ./slidecast/plugins/slidecast    # load without installing
claude plugin validate ./slidecast/plugins/slidecast # validate the manifest

Run /reload-plugins after edits to pick up changes.

Project layout