Speed changes alter the timeline
At 2×, a 60-second source becomes about 30 seconds. At 0.5× it becomes about 120 seconds. The video timestamps and audio samples must be transformed together.
Know the pitch tradeoff
This browser workflow changes playback speed and audio pitch together, similar to changing tape speed. High-quality pitch preservation requires a dedicated time-stretch algorithm and is not claimed here.
Use moderate factors
Extreme slowdowns duplicate or stretch information the source never contained, while extreme speedups can make motion hard to follow.
Review synchronization
Play the exported beginning, middle and end. A useful speed tool must keep spoken audio aligned with the corresponding frames.
Official marketplace references
Requirements can change. Review the source before publishing an important listing.
Mediabunny browser media toolkit documentation ↗