Context and scope

Timelapze is a iOS and MacOS application for creating screen and camera time-lapsed videos built off a slower-than-realtime ScreenCaptureKit Recording Engine.

Goals and non-goals

Color accurate, slower-than realtime recording without any editing, post-processing and composition tool.

Design

Both the Menu-bar MacOS app and iOS app are simple which only allows screen and application selection or camera selection. In configuration, both the frame rate and speed multiple can be selected.

APIs

Standard Model, View, View-Model setup.

Data Storage

All data is stored locally in a user-specified directory. No synced configuration is stored.

Code / Pseudo Code

func handleFrame(frame){
  if(frame.timestamp < previousStoredFrameTimeStamp + 1. / FrameRate){
    return
  }

  saveFrame(frame);
}

Degree of Constraints

Both system specifications and software limit the use of applications. ScreenCaptureKit limits the frame rate and resolution of recordings. Memory and compute requirements practically limit to pre-defined frame rates.

Alternatives Considered

Recording alternate frames using Python and OpenCV was initially built as a proof of concept. Limitations to recordings granularity and large bundle sizes lead to a native application built in Swift.

Cross-cutting concerns

Time lapse projects with unknown duration require upfront flexibility in storage and frame rates.