sync.video

sync.video fixes audio and video that don't line up. Drop one video and it detects claps and hits to find the delay, or drop a video with a separate mic recording or up to eight camera angles and it matches them by the shape of their sound, with a confidence figure for every answer. Check it in slow motion and nudge the sound earlier or later in 10 ms or 1 ms steps, then export: the picture is always copied as it is, so no quality is lost. Extras include a sync player for playing one video in step across several devices, a beat-sync video maker, and a delay test, BPM and tap-tempo tools. Everything runs in your browser and nothing is uploaded. Free, no account, no watermark.