Load your video, drag the quality slider to balance size against sharpness, and export. The compressed file typically downloads much faster than the original.
It depends heavily on the source: a phone video with a high bitrate can often shrink by 50-80% at a moderate quality setting with little visible difference.
It adjusts the CRF (constant rate factor), FFmpeg's quality-vs-size control — lower values mean higher quality and larger files, higher values mean smaller files with more visible compression.
Resizing shrinks the frame dimensions, while compression reduces the bitrate at the same resolution — this tool focuses on bitrate, so use the Resizer alongside it for maximum size reduction.