Compress iPhone videos without losing quality

Short answer: Your iPhone records video at a generous bitrate, because it has to encode in real time while you film. Re-encoding the same frames with HEVC afterwards, without that time pressure, usually gives a much smaller file at the same resolution and frame rate. Photos cannot do this, so you need an app that re-encodes on the device. For new recordings, you can also choose settings that make smaller files from the start.

Why iPhone videos are so big

Encoding a video well takes time, and the camera has none: every frame has to be written as it arrives. To keep quality high anyway, the iPhone uses a high bitrate. The file is bigger than the picture needs. A second, unhurried pass can describe the same frames with far fewer bytes.

The format matters too. High Efficiency records HEVC (H.265). Most Compatible records H.264, which needs noticeably more space for the same quality. And ProRes, on Pro models, can be up to 30 times larger than HEVC.

Check your camera settings first

1. Open Settings › Camera › Formats and choose High Efficiency.
2. Open Settings › Camera › Record Video. Pick the lowest resolution and frame rate you are happy with; the screen shows roughly how much a minute takes for each option. 1080p at 30 fps is plenty for most everyday clips.
3. If you have a Pro model and do not edit professionally, keep Apple ProRes off in Formats.

These settings only affect new recordings. The videos already in your library stay as big as they are.

Shrinking videos you already have

To make an existing video smaller without cutting it, it has to be re-encoded. There are three ways:

• Trim it in Photos with Edit if only part of it matters. This is the one built-in option, and it shortens the video rather than compressing it.
• Export it at a lower resolution with an editing app such as iMovie. That makes a new copy, so delete the original afterwards.
• Re-encode it with HEVC at the same resolution with an app that does this on the device, then keep the smaller version.

Be wary of apps that upload your videos to compress them on a server. Your videos do not need to leave the phone for this.

What does DustFox do differently?

Shrink Videos re-encodes your videos with HEVC on the iPhone. With the default Keep Quality setting, only the encoding changes: resolution, frame rate and HDR stay as they were. It reads each video’s codec first and suggests only the ones where it can win real space, so already-efficient videos are skipped. The smaller copy is added to your library and, after you confirm, the original waits 30 days in Recently Deleted. On iOS 26 and later the queue keeps running in the background. Nothing is uploaded.