Do you upload my video?
No. Speed processing runs locally in your browser.
Change MKV Video Speed
Change MKV video speed and export locally — no uploads.
Frequently asked questions
Will this change video quality?
Speed changes require decoding and re-encoding, which may slightly change quality depending on codec settings.
Does changing speed affect audio pitch?
This tool currently adjusts speed by resampling audio, so pitch may change. Pitch-preserving tempo is planned.
Why does processing take time?
We need to decode and re-encode to create a new timeline with updated timestamps.
Which browsers are supported?
For best results, use the latest Chrome / Edge with WebCodecs support.
Which formats are supported?
Common inputs include MP4/WebM/MOV/MKV. Output supports MP4/WebM/MOV/MKV.