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Earlyn

How much disk space screen memory takes.

At Earlyn's default 2,560-pixel capture, a busy hour of screen memory takes about 9 MB, which is around 160 stored moments at roughly 52 KB of picture and 4.5 KB of text each, and a still screen stores nothing.

Updated Read as Markdown

Per hour, per day, per history window

PeriodPicturesTextTotal
One busy hour8.3 MB0.7 MBabout 9 MB
An 8-hour workday66 MB6 MBabout 72 MB
A month of workdays (22)1.5 GB0.1 GBabout 1.6 GB
Pro's 90-day window (≈64 workdays)4.2 GB0.4 GBabout 4.6 GB
Assumes every hour of the day is busy; real days are usually lighter. Meeting audio, when kept, adds about 14 MB an hour. Settings → Storage shows your own rate.

Why so little

  • Earlyn keeps a frame only when the text on screen changed; ScreenCaptureKit sends nothing while the screen is still.
  • Frames go into HEVC video made by the Mac's hardware encoder, which stores the small differences between moments very compactly.
  • Terminals change every second and produce the most moments, about 1.4 KB of text each.

Resolution: what 2,560 pixels buys

Capture widthPicture per momentText legibility
1,440 px30 KBReadable but soft for 11–13 px text
2,560 px (default)52 KBNear crisp
Native (3,420 px on a 2× display)87 KBCrisp
A scripted 10-minute session, 27 stored moments, the same screens at each width. Encoding cost 0.6–2.7 ms per frame at every width.

When an app exposes no text, Earlyn reads the picture with on-device text recognition. On a 2× display the 1,440-pixel stream was useless for that (0–16% of words recovered); at 2,560 pixels recovery came within 4 to 9 points of a native-resolution screenshot:

AppWords recovered at 2,560 pxAt native resolution
Safari85%93%
Xcode75%79%
Zed88%92%
Slack50%59%
Recall against the text the app exposes through Accessibility. Apple's slower “accurate” recognition added only a few points at three to four times the cost.

Cost of encryption

Scrubbing the timeline over encrypted segments took 5.7 ms per thumbnail and 6.6 ms per full frame, the same as unencrypted, because a segment is decrypted once into memory and then read from there.

Questions

Which Mac were these measured on?
Earlyn's development Mac, an Apple Silicon MacBook with a 2× Retina display, in September 2026, with the app's own debug benchmarks.
Can I make it smaller?
Yes: shorten the history window, set shorter windows for busy apps, or lower the capture quality in Settings → Storage.

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