SpeedSync for YouTube™

Set a listening pace in words per minute. SpeedSync adapts captioned passages and gives caption gaps a separate speed.

SpeedSync adjusts YouTube™ playback to the listening pace you set in words per minute. Choose a target such as 180 WPM. For each captioned passage, SpeedSync estimates the source speaking rate and adjusts playback toward your target. A passage at 120 WPM plays around 1.5x. A passage at 240 WPM plays around 0.75x. Your minimum and maximum speed limits still apply. Caption gaps use a separate speed. You can keep pauses at normal speed, move through them faster, or turn on Learning guard to cap speech speed and preserve short caption pauses. SpeedSync works with recorded videos that have timed captions. You can also import a matching VTT, SRT, or YouTube JSON3 transcript for the current video. Privacy: - No Rekh account - No analytics or telemetry - No microphone or audio capture - Settings stay in Chrome local storage - Caption data and imported transcripts stay in page memory and are not sent to Rekh SpeedSync estimates speech from caption timing. Incomplete or inaccurate captions can affect the result. Live videos, Shorts, mobile YouTube, and embedded players are not supported. SpeedSync is an independent Rekh product. YouTube is a trademark of Google LLC. Use of this trademark is subject to Google Permissions.