Developer Builds Free In-Browser Video Dubbing Tool After AI Services Cost Too Much

A developer wanted to learn game development from a Spanish-language Godot course but found subtitles impractical for screencasts, where watching the screen and reading simultaneously is nearly impossible. Pricing out commercial dubbing services, he found Rask would cost around $540 for a six-hour course, while HeyGen offered a more reasonable $49 option, but both platforms lacked a simple one-time, no-subscription path for personal use. He built an open tool called Dub Any Video that runs locally in the browser, using a six-stage pipeline: audio extraction, transcription via Whisper, translation, text-to-speech via Piper, and audio-to-video synchronisation. The hardest engineering challenge turned out to be timing — fitting translated speech, which often runs longer than the original, into fixed video windows without distorting pitch or breaking the viewer's sync with on-screen actions. The solution combined speech speed adjustment capped at 1.3x, localised video slowdown, and allowing audio to spill into natural gaps rather than truncating it.