GPU-accelerated real-time preview with RAM caching, scrubbing tiers, transform handles, and multi-output support.
All preview rendering in Masterselects runs on the GPU via WebGPU — from the main preview canvas to additional output windows. This means every frame you see, even during scrubbing, is a fully composited GPU render.
All preview rendering — compositing, effects, and frame caching — is performed on the GPU. A discrete GPU or a GPU with dedicated VRAM will significantly improve preview performance on complex compositions.
The 900-frame composite cache stores fully rendered ImageData on the CPU side and uses LRU eviction when either the frame count or byte limit is reached. The 60-frame GPU cache holds those same frames as GPU textures for zero-upload-cost playback.
You can reduce the internal render resolution to save memory and improve caching speed:
Setting
Render resolution
Cache savings
Full (100%)
1920×1080
—
Half (50%)
960×540
75%
Quarter (25%)
480×270
~94%
Quality is set via the dropdown in the bottom-left of the Preview panel. Export always uses the full composition resolution regardless of preview quality.
Dragging the playhead triggers the scrubbing cache, which is a 3-tier system designed to deliver the fastest possible frame for any playhead position:Tier 1 — VRAM texture cache
GPU textures keyed by source file and quantized frame time (30 fps boundaries). Holds up to 300 frames (~2.4 GB at 1080p). Provides instant display for recently visited frames with no CPU–GPU upload.Tier 2 — Last-frame cache
One GPU texture per video element that stores the last valid decoded frame. Displayed immediately when seeking to an uncached position, preventing a black flash while the correct frame decodes.Tier 3 — RAM Preview composite cache
If a fully composited frame is cached for the target time, it is displayed directly from the CPU-side ImageData buffer. This is the most accurate representation and requires no further rendering.
Click any layer in the preview canvas to select it. The corresponding clip is also selected in the timeline. Non-selected layers show dashed white outlines; the selected layer shows a solid bounding box with handles.
Use edit mode with keyframe recording enabled to animate a layer’s position by dragging it on the canvas at different playhead positions — no need to type coordinates.
The Speed property on any clip supports varispeed scrubbing. With speed keyframes you can ramp smoothly between rates within a single clip. Negative speed values reverse playback.See Keyframe animation — speed keyframes for details on animating speed over time.