Two Settings Cause Most of the Trouble

HEVC (H.265). Since iOS 11, iPhones record in HEVC by default ("High Efficiency"). It makes files smaller than the older H.264 format, but many Windows PCs need an extra codec to play it, and some office and government software won't accept it.

HDR (Dolby Vision). Newer iPhones record HDR video. On a screen or player that doesn't handle HDR, it looks grey, flat or "washed out".

And 4K files are big: a 44-second 4K HDR clip from an iPhone we tested was 279 MB, about 6 MB for every second.

Fix: Convert to a Normal MP4 (and Make It Smaller)

Open Compress iPhone video on the iPhone (Safari, iOS 16.4 or newer) or on the computer you copied the video to. Choose the video and either tap a size limit or pick a quality (High, Medium, Low). The result is an MP4 in H.264 with standard colours, which plays on Android, Windows, Mac and in every app. The video is never uploaded.

In our test (20 October 2026) the 279 MB iPhone video came out at 106 MB on High quality with no limit, still 4K, and at 24.4 MB with a 25 MB limit.

On a Windows PC that can't decode HEVC, the tool switches to a slower built-in decoder automatically. Expect a few minutes for a long 4K clip.

Avoid It Next Time

  • Settings → Camera → Formats → Most Compatible: records H.264 instead of HEVC. Files are bigger but play everywhere.
  • Settings → Camera → Record Video: 1080p instead of 4K makes files roughly a third of the size.
  • HDR Video (under Settings → Camera → Record Video on recent iPhones): switch it off if you mostly share videos with Android or Windows users.