demodsl 2.0.0

DSL-driven automated product demo video generator

DemoDSL

DSL-driven automated product demo video generator.

Define your product demos in YAML or JSON — DemoDSL handles browser automation, voice narration, visual effects, video editing, and final export.

Features

• YAML & JSON DSL — Declarative scenario definitions with steps, effects, and narration
• Browser Automation — Playwright-powered capture (Chrome, Firefox, WebKit)
• Voice Narration — ElevenLabs TTS with automatic sync to video
• 18 Visual Effects — Spotlight, confetti, glitch, neon glow, and more
• Video Composition — Intro/outro, transitions, watermarks via MoviePy
• Audio Mixing — Background music with smart ducking during narration
• Multi-format Export — MP4, WebM, GIF + social media presets (YouTube, Instagram, Twitter)

Installation

pip install demodsl

Then install Playwright browsers:

playwright install chromium

Quick Start

1. Generate a template:

demodsl init

2. Edit demo.yaml:

metadata:
  title: "My Product Demo"

scenarios:
  - name: "Main Demo"
    url: "https://myapp.com"
    steps:
      - action: "navigate"
        url: "https://myapp.com"
        narration: "Welcome to our product!"
        effects:
          - type: "spotlight"
            duration: 2.0

pipeline:
  - generate_narration: {}
  - edit_video: {}
  - mix_audio: {}
  - optimize:
      format: "mp4"

3. Run:

demodsl run demo.yaml

4. Validate without executing:

demodsl validate demo.yaml

CLI Commands

Command	Description
demodsl run <config>	Execute the full pipeline
demodsl validate <config>	Validate config without executing
demodsl init	Generate a minimal template
demodsl init -o demo.json	Generate a JSON template

Options

• --output-dir, -o — Output directory (default: output/)
• --dry-run — Log all steps without executing
• --skip-voice — Skip TTS generation (dev mode)
• --verbose, -v — Debug logging

Architecture

DemoDSL uses a modular architecture with 5 design patterns:

Component	Pattern	Purpose
Providers	Abstract Factory	Voice, Browser, Render provider instantiation
Browser Actions	Command	Navigate, Click, Type, Scroll, WaitFor, Screenshot
Pipeline	Chain of Responsibility	8 stages with critical/optional error handling
Visual Effects	Registry + Strategy	18 effects in 2 registries (browser JS + post-processing)
Video Composition	Builder	Progressive intro → segments → watermark → outro assembly

Pipeline Stages

Stage	Critical	Description
restore_audio	Optional	Denoise + normalize audio
restore_video	Optional	Stabilize + sharpen video
apply_effects	Optional	Post-processing visual effects
generate_narration	Critical	TTS generation + video sync
render_device_mockup	Optional	Device frame overlay
edit_video	Critical	Intro, outro, transitions, watermark
mix_audio	Critical	Voice + background music ducking
optimize	Critical	Final encoding + compression

Environment Variables

Variable	Description
ELEVENLABS_API_KEY	ElevenLabs TTS API key
OPENAI_API_KEY	OpenAI API key (tts-1-hd)
GOOGLE_APPLICATION_CREDENTIALS	Path to Google Cloud service account JSON
AZURE_SPEECH_KEY	Azure Cognitive Services Speech key
AZURE_SPEECH_REGION	Azure region (default: eastus)
AWS_ACCESS_KEY_ID	AWS access key for Polly
AWS_SECRET_ACCESS_KEY	AWS secret key for Polly
AWS_DEFAULT_REGION	AWS region (default: us-east-1)
COSYVOICE_API_URL	CosyVoice API server URL (default: http://localhost:50000)
COQUI_MODEL	Coqui TTS model name (default: xtts_v2)
COQUI_LANGUAGE	Language code for Coqui TTS (default: en)
PIPER_BIN	Path to piper binary (default: piper)
PIPER_MODEL	Path to Piper .onnx voice model (required for piper engine)
LOCAL_TTS_URL	OpenAI-compatible local TTS server URL (default: http://localhost:8000)
LOCAL_TTS_API_KEY	API key for local TTS server (default: not-needed)
LOCAL_TTS_MODEL	Model name for local TTS server (default: tts-1)
ESPEAK_BIN	Path to eSpeak-NG binary (default: espeak-ng)

Without the required credentials, DemoDSL falls back to a silent dummy provider for development.

Vintage / debug providers: espeak and gtts need no API key — ideal pour le prototypage rapide. espeak donne un son robotique rétro, gtts utilise Google Translate (nécessite internet + pip install gtts).

License

MIT