What It Does
Mask Prompter 3 is an AI-driven rotoscoping plugin for Premiere Pro (and After Effects) that generates video mattes from text descriptions, point clicks, or drawn rectangles. Instead of painting frame-by-frame with Rotobrush, you type something like “river” or “car.person” and the plugin identifies and tracks those elements across your footage.
All processing runs locally on your machine using a fully C++ implementation. No data is uploaded anywhere, and rendering speed stays consistent from Full HD 8-bit up to 4K 32-bit.
Key Features
Segment Anything 3 integration. The plugin uses Meta’s SAM3 model for matte generation, handling complex subjects with strong edge detail.
Text-based matting. Describe objects in plain language and the plugin isolates them. Use dot notation to separate multiple objects in a single prompt, for example “car.person.bike” to key all three at once.
Bounding box detection. Draw rectangles around any number of objects when text prompts aren’t precise enough. Useful for distinguishing two similar subjects in the same frame.
High-quality refinement module. A secondary refinement pass sharpens matte edges, helpful for hair, fur, or foliage where base segmentation tends to lose detail.
Video stability. The tracker maintains consistent results across clips. The developer demonstrates this with a river matte created from a single placed point.
Multiple output modes. Export as an overlay for preview, a black-and-white matte, or direct alpha channel transparency. This makes it straightforward to combine with other effects or composite over new backgrounds.
Hardware acceleration. Optimized for NVIDIA GPUs (8GB VRAM or more) on Windows, and Apple Silicon Macs running macOS Sequoia or newer with 16GB RAM minimum. Non-NVIDIA Windows machines will work but render slowly.
Who It’s For
Editors and VFX artists who regularly need to isolate subjects, replace backgrounds, or create selective color treatments without the time investment of manual rotoscoping. Particularly useful for documentary footage, run-and-gun shoots, or any situation where green screen wasn’t an option on set.
Premiere Pro support was added in February 2026 (version 3.4.47). Check the documentation for current limitations specific to the Premiere Pro implementation.
Pricing
Mask Prompter 3 costs $49.99 as a one-time purchase. Users who bought a previous version after April 11, 2025 can upgrade for free. Earlier purchasers can upgrade for $35. A free trial download is available directly from the product page.