Proxy editing: edit small, export full

The problem proxies solve

A modern phone shoots 4K at 60 frames per second. Playing that back is a solved problem — the hardware decoder handles it. Editing it is a different workload entirely:

• During a transition, two streams decode at once and blend per pixel.
• A picture-in-picture overlay means two simultaneous streams for its whole duration.
• Scrubbing asks the decoder for arbitrary frames out of order, which is far more expensive than playing forwards.
• Colour, scale and rotation each add a pass over every pixel of every frame.

Stack those and even a flagship phone drops frames. The result is a preview that stutters, and an editor you cannot trust because you cannot see what you are doing.

How ProCut does it

When you import a clip, ProCut generates a 960p proxy — a smaller, lighter copy of the same footage — plus the thumbnail strip and the audio waveform for the timeline. From then on:

This is exactly what desktop editors do with 6K and 8K camera footage. The difference is that on a desktop you usually have to set it up; in ProCut it happens on import without a setting to find.

What the proxy does not affect

Worth stating plainly, because "proxy" makes people nervous about quality:

• Your original files are never modified. ProCut does not write to your camera roll.
• Export reads the originals, at whatever resolution you chose.
• Edit decisions are stored as frame numbers, so a cut made against the proxy is the same frame in the full-resolution export.
• Colour and effects are parameters applied at render time, not baked into the proxy.

Native engines, not a shared wrapper

The other half of performance is what ProCut is built on. There is no cross-platform UI framework and no shared rendering layer:

Three engines, one shared timeline model — checked against the same golden-frame tests so the output matches.

The cost of that decision is three codebases. The benefit is that every platform gets its own hardware decoder, its own GPU compositor and its own encoder, with nothing lost in translation. It is also why the app launches quickly and the binary is small.

Getting the most from modest hardware

1. Let imports finish. Proxies, thumbnails and waveforms are being built; starting to scrub immediately is the one moment the timeline is slowest.
2. Keep storage free. Proxies need room, and a device close to full slows down everything, not just ProCut.
3. Split long recordings. One forty-minute clip is heavier to work with than the three useful minutes you actually need.
4. Add effects after the cut. Every graded, scaled or keyframed layer is compositing work on every preview frame.
5. Close background apps before a long 4K export — thermal headroom is what keeps the encoder at full speed.

What to expect while editing

• Import: a short processing pass per clip, proportional to its length.
• Scrubbing: immediate, including on stacked lanes.
• Preview with effects: smooth; heavy stacks of layers may soften briefly while the compositor catches up.
• Export: usually a fraction of the project's duration, driven by complexity more than by length.

Battery, heat and long exports

Sustained video encoding is one of the few things that can push a phone into thermal throttling. When that happens the encoder slows down to protect the device, and an export that should take ninety seconds takes four minutes.

What actually helps, in order of effect:

1. Take the case off for a long 4K export. Thick cases are insulation, and they are the single biggest controllable factor.
2. Plug in — but not into a fast charger. Charging generates its own heat; a slower supply keeps the device cooler while still holding the battery steady.
3. Close background apps, particularly anything using the camera, GPS or a video call.
4. Do not leave it in the sun. Obvious, and still the reason half of all slow exports happen.

What ProCut writes to disk

Your source media is never modified and never duplicated at full resolution.

If storage is tight, the fastest win is deleting finished projects rather than individual files — that clears the proxy, thumbnails and waveform cache together, and leaves your original footage exactly where it was.

Frequently asked questions