iOS Photo Editing App - need advice regarding photo editing engine

We are working on an iOS photo editing application, and are planning to overhaul the photo editing engine for performance reasons. We are looking for advice on how to structure our photo editing engine to make real time editing possible. We are currently using Core Image, and this works okay, but we are having issues with real time photo editing performance and exporting at high resolution. For example if we add multiple textures, and change brightness, the app slows down. Should we stick to core image, or use something else? Is core image the bottleneck, or our implementation of i. The app features: high resolution photo editing, image adjustments (brightness, saturation etc,), filters using LUTs, texture overlays, borders, and more. Eventually real time video editing will need to be added as well. Our goal is to make our app work as well as Polarr, Darkroom, VSCO and Lightroom mobile. These apps (especially Polarr) seem to have no issues whatsover with performance. Deliverables A document with a plan for our image processing engine that can be handed to our dev team for implementation.