SmartSub is an open-source desktop tool (5.5k Stars, MIT license) that packs the entire audio/video subtitle and dubbing pipeline — speech-to-text, translation, proofreading, TTS dubbing, burn-in — into one app. Supports 8 transcription engines (whisper.cpp/faster-whisper/FunASR/Qwen3-ASR/FireRedASR/Parakeet etc.), 20 translation services, local TTS with zero-shot voice cloning. Built-in AI assistant (multimodal visual diagnostics + Agentic tool-calling) and 111 MCP tools + CLI commands for Cursor/Claude Code/Codex integration. Full pipeline runs completely free, cross-platform Windows/macOS/Linux with full GPU acceleration.