Question 1

Why does a part start a little earlier or later than I set?

Accepted Answer

A compressed video is stored as occasional complete pictures (keyframes) with the frames in between described as changes, so a copy can only begin on a keyframe. A part you keep starts at the keyframe just before your time, so nothing you wanted is lost. After a part you cut out, the video picks up at the keyframe just after it, so nothing you cut out comes back. Either way the shift is usually under a few seconds, ends are exact to the frame, and the times used are listed after saving.

Question 2

Can I join videos from different cameras or phones?

Accepted Answer

Yes. Clips with the same codec, picture size and encoder settings are joined by copying. When they differ, the page converts each to H.264 at the first clip's size so they can be joined, and says so. That conversion is the only step that re-encodes, and it uses your browser's video encoder.

Question 3

How does rotating work without re-encoding?

Accepted Answer

The file gets a rotation setting that players read, the same way phones mark a video recorded on its side. Every common player honours it - phones, browsers, VLC, QuickTime and Windows Media Player - though some video editors ignore it.

Question 4

Is there a size or length limit?

Accepted Answer

No limit is set. The finished video is built in memory before it downloads, so a file of several gigabytes needs a computer with plenty of RAM; on a phone, shorter videos work best.

Question 5

Is my video uploaded?

Accepted Answer

No. The video is read and written by your browser, so private recordings stay on your computer and nothing waits on an upload.

Free video cutter - no re-encoding