Speed-Pitch Changer is a Firefox extension designed to modify the pitch of audio in web videos based on their playback speed. This tool is particularly useful for users who enjoy creating or listening to 'nightcore' music, allowing them to easily adjust audio settings. The extension offers unlimited pitch adjustment values and supports web audio, although functionality may vary across different websites.

Users can independently change the pitch of a video element without affecting its speed, utilizing the provided and buttons. Additionally, the extension allows users to select specific websites for activation and customize keyboard shortcuts for quick access. Default shortcuts include the numeric keypad keys: *, +, -, and . This functionality enhances user experience by providing flexible audio control while enjoying multimedia content.