Shortcast automates the creation of short-form video content (TikTok, Reels, YouTube Shorts) from long-form recordings. This native macOS app finds viral moments, transcribes audio, generates platform-specific captions, reframes footage to vertical, and schedules posts, all processed 100% on-device for privacy. It significantly reduces manual effort for content creators.

How It Works

Utilizing Swift and Apple's MLX, Shortcast performs all AI tasks locally. WhisperKit (large-v3) transcribes audio, while Gemma 4 (12B/E4B) or Qwen 3.5 9B models act as the "Director LLM." This LLM analyzes the full transcript in one pass to identify key clips and craft tailored captions. Horizontal video is automatically reframed to 9:16 using Vision face tracking. No data leaves the Mac until explicit publishing.

Quick Start & Requirements

Download Shortcast.dmg and drag to Applications. Bypass Gatekeeper with xattr -dr com.apple.quarantine /Applications/Shortcast.app in Terminal. Building from source requires Xcode 16+ and XcodeGen. Prerequisites: macOS 15+, Apple Silicon required. Models (Gemma 4, WhisperKit) download on first use. An Upload-Post API key is needed for publishing/scheduling.

Highlighted Details

• On-Device Processing: Transcription, moment finding, captioning, and reframing occur entirely locally.
• Unified LLM Workflow: Single