avsync

AVSync is a browser-based utility designed to synchronize external high-quality audio tracks with video files. It operates as a local-first tool, ensuring that user media remains on the local machine during processing. Key capabilities include: - Automatic alignment estimation using spectrogram feature correlation. - Manual refinement tools including frame-scale nudges, spectrogram dragging, and tempo refinement for drifting recordings. - Support for negative offsets, allowing clean tracks to start after the video begins. - Multiple preview modes: clean audio, blended audio, and original video audio. - Local rendering and export to MP4 using FFmpeg WASM with AAC replacement audio and video stream copying. - Native light and dark theme support. The tool utilizes WebAudio, Canvas2D, and WebAssembly to handle decoding, analysis, and rendering directly in the browser.