VIDEO SPEED CONTROL
Speed up a lecture recording, make a funny slow motion. Voice pitch preserved. 100% offline.
MP4, MOV, WebM, MKV • max 500MB
About Free Video Speed Up & Slow Down (Audio Protected)
Watch a long lecture at 2x or make a funny 0.5x slow motion: video speeds up with setpts, audio with pitch-safe atempo — no chipmunk voice. Fully in your browser.
- ✓9 speeds: from 0.25x slow motion to 3x fast watching.
- ✓Pitch-safe audio: speeds up with an atempo chain without pitch change.
- ✓Silent video protection: automatically converts silently if there is no audio stream.
- ✓Drop-audio option: uncheck the box and the file gets smaller, processing faster.
- ✓Quality output: H.264 + superfast + CRF 23 + faststart.
- ✓Zero upload: everything stays on your device up to the 500MB limit.
- 1.Select your video or drag it into the area (max 500MB).
- 2.Pick a speed (e.g. 1.5x–2x for lectures, 0.5x for comedy).
- 3.Decide whether to keep the audio.
- 4.Press the "Convert" button.
- 5.Preview and download as MP4.
Privacy-First Architecture
Unlike 99% of online free video speed up & slow down (audio protected) tools, Mr. Robot Help operates entirely on your device. When you upload a file, it never travels to a remote server. Instead, we utilize modern browser technologies like WebAssembly (Wasm) and FFmpeg.wasm to process your data locally.
This approach offers three major benefits:
Your sensitive files stay in your browser's memory. No leaks, no hacks, no logs.
Processing speed is limited only by your CPU, not your internet upload speed.
Since we don't pay for cloud bandwidth, we don't impose artificial file size restrictions.