How to Compress iPhone Videos in the Background (iOS 26)

Published October 19, 2026.

Compressing a few hundred videos takes a while. Each one is decoded and encoded again, and older clips may have to download from iCloud first. You probably don't want to keep your iPhone on the HEVCut screen for that long.

iOS 26 lets an app keep a job you started running after you leave, with a progress bar shown by the system. HEVCut uses it for its compression queue. Here's how to start a run, what can make iOS pause it, and what happens when it does.

Quick answer

Open Compress in HEVCut and start a run: tap Compress for the whole list, or tap videos to queue them.
Leave the app the normal way. Don't close it from the app switcher.
iOS shows the progress in a Live Activity, for example "Shrinking 3 of 12 · 52%".
If iOS stops the task, HEVCut pauses the queue, sends a Compression paused notification, and resumes when you open the app.
When the run ends, review the results in HEVCut. Nothing is deleted until you confirm it.

How background processing works in iOS 26

Apple calls this a continued processing task (BGContinuedProcessingTask for developers). According to Apple's documentation, the task starts in the foreground and has to come from something you did, such as tapping a button. When you leave the app, the system shows the task's progress in a Live Activity, and you can cancel it from there.

The system decides how long the task runs. Apple's documentation says it can end the task under resource constraints, ending tasks that show little progress first, and that closing the app in the app switcher cancels it.

HEVCut asks iOS for the task at the moment you leave the app, not when you tap Compress. A short run that you watch to the end never puts a progress bar on your Lock Screen.

Compression continues in the background, scanning doesn't

Only compression uses this background task. The library scan, including the passes that find duplicates and clutter, needs HEVCut open: it stops when you leave and picks up where it left off when you return. On a new install, let the first scan finish with the app open, then start compressing and leave.

Start a background compression run

Compress videos in the background with HEVCut

01
Plug in your iPhone if you can and turn off Low Power Mode. iOS weighs battery level and power settings when it decides how much background time an app gets.
02
Open HEVCut and tap Compress on Home. The Compress button at the top shows how much your library can shrink and how many items it will work through.
03
Check your settings: tap the gear (Settings) in the toolbar, then Video Compression. Standard is the default. Turn on Keep original resolution if you want 4K videos to stay 4K.
04
Tap Compress to work through the whole list, or tap individual videos to queue only those.
05
Leave HEVCut by swiping up, locking the screen, or switching apps. Don't close it from the app switcher, because that cancels the run.
06
When the run finishes, open HEVCut. The dock at the bottom of Compress shows how many originals are waiting and how much space deleting them frees. Review before you delete anything.

What you see while it runs

After you leave the app, the system progress bar takes over. Its title reads "Freeing up space" at first, then something like "1.2 GB freed so far". The line below names the current step:

"Downloading 3 of 12 · 52%" while an original downloads from iCloud
"Shrinking 3 of 12 · 52%" while the video is compressed
"Waiting for network · 3 of 12" when an iCloud download is waiting for a connection

The bar covers the whole run and also moves within the current item, so it keeps advancing during a long clip.

When iOS may refuse or stop the task

Background time on iPhone is managed by the system and isn't guaranteed. In its WWDC25 session on background tasks, Apple says network availability, CPU load, device activity, thermal state, and battery level all inform scheduling decisions, and that settings such as Low Power Mode, Background App Refresh, and Low Data Mode influence them too. Apple's support page adds that Low Power Mode reduces background activity.

These habits give a long run the best chance to finish:

Charge while it runs. Battery level is one of the inputs.
Turn off Low Power Mode for the duration of the run.
Keep the iPhone cool. Thermal state is another input, so a phone in a hot car or under a pillow is a poor place for a long job.
Don't close HEVCut from the app switcher. Apple's documentation says that cancels running tasks.
Use Wi-Fi if many originals are in iCloud. Downloads are part of the run.

HEVCut asks iOS to start the task right away or not at all. Apple's documentation says such a request is declined when the system can't start it immediately, for example when it has reached its maximum number of concurrent tasks. HEVCut then only gets the short time iOS gives any app after you leave it, so keep it open for that run. While HEVCut is on screen, your iPhone won't auto-lock.

What happens when iOS pauses compression

When the task ends early, whether iOS ended it or you tapped stop on the progress bar, HEVCut pauses the run instead of cancelling it:

Finished items stay finished. Each compressed video is saved to your library as soon as it's done.
The current item keeps its place. It goes back to the front of the queue and its encode starts again from the beginning, because a partly written video file can't be used.
The rest of the queue is kept, including a Compress run over the whole list.
You get a Time Sensitive notification titled Compression paused, for example "1.2 GB freed so far. Open HEVCut to pick up where you left off."
Opening HEVCut resumes the run and clears the notification.

To end a run for good, tap Stop in HEVCut. A stop from the system progress bar only pauses it.

Let the pause notification through

Time Sensitive notifications can break through a Focus when you allow them. Go to Settings → Notifications → HEVCut and check that Time Sensitive Notifications is on, then check which apps your Focus allows. Apple explains both in Change notification settings on iPhone and Allow or silence notifications for a Focus.

If notifications are off

When a run looks like it will take a minute or more, HEVCut checks whether it can notify you. If you've never answered the notification prompt, iOS asks then. If you turned notifications off, HEVCut shows This Will Take a While with an Open Settings button, at most once a day.

HEVCut compresses the videos already in your Photos library, on your iPhone, and keeps going in the background on iOS 26.

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Originals stored in iCloud

With iCloud Photos and Optimize iPhone Storage, full-resolution originals are kept in iCloud and your iPhone holds smaller copies when space is needed. HEVCut needs the full original to compress a video, so it downloads each one first. In the list, those items carry a cloud badge ("Stored in iCloud").

Apple's documentation says continued processing tasks can use the network in the background, so downloads carry on after you leave the app. If a download can't finish because you're offline, HEVCut skips that item for this run, tells you once with iCloud Download Unavailable, and carries on with videos already on your iPhone. Start another run later to pick up the ones it skipped.

How big a run can be

Compress works through every eligible item in the current list, filters included. Narrow the list by date, album, or type first if you only want part of the library.
With Pro, you can also tap up to 500 items into the queue by hand.
On the free tier, a run stops when your free compressions are used up.
HEVCut encodes one video at a time. Library compression and External drive compression never run together. If you try, HEVCut shows Already Compressing and names the one that is running.
If your iPhone runs out of free space during a run, the queue pauses with the current item kept in line.

Pro tip

Pick your settings before a long run. They apply to every item picked up after a change, so switching presets halfway leaves you with a mixed batch. Keep 4K or drop to 1080p? explains each preset.

On iPad and Mac

iPad on iPadOS 26 works the same way as iPhone. On a Mac, HEVCut keeps encoding while you use other apps, with no system task needed; quitting it stops the run. More in How to compress your Photos library on a Mac.

After the run: review, then delete

Compression never replaces anything by itself. Each compressed video is saved as a new item next to its original, with the same capture date, location, favorite status, and albums. Open a video to compare and choose Keep Compressed or Revert. For the whole batch, tap Delete in the dock at the bottom of Compress (for example "12 originals · Frees 3.1 GB"), or Undo in the toolbar to remove the compressed copies and keep every original.

Deleted originals go to Recently Deleted in Photos, where Apple keeps them for 30 days. See all HEVCut features and what's new.

Frequently asked questions

Does HEVCut upload my videos to compress them?

No. Compression runs on your iPhone, iPad, or Mac, and your videos are never uploaded. The only network use during a run is downloading your own originals from iCloud Photos when they aren't stored on the device.

Why did my background compression stop?

iOS ends background tasks when resources are tight. Apple lists battery level, thermal state, and settings such as Low Power Mode among the things that affect scheduling. Closing the app from the app switcher also cancels the task. HEVCut pauses the queue, sends a Compression paused notification, and resumes when you open the app.

Does the library scan also continue in the background?

No. Only compression runs in the background. The library scan, including finding duplicates and clutter, stops when you leave HEVCut and resumes where it left off when you open the app again.

Can I lock my iPhone while HEVCut compresses?

Yes. Locking the screen counts as leaving the app, so the run continues with the system progress bar if iOS grants the task.

How do I stop a background run completely?

Open HEVCut and tap Stop in Compress. Stopping from the system progress bar only pauses the queue, and it picks up again the next time you open the app.