Online ASTC Viewer & Converter - Open .astc Files & Convert to PNG
Open, view, and inspect .astc texture files online in your browser. Preview RGBA channels, analyze 14 standard 2D block footprints (4×4 to 12×12), and convert ASTC textures to PNG images instantly without server uploads.
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Upload ASTC File
Drag and drop a ASTC file here
or
Key Features
100% Browser-Based
All decoding runs locally via WebAssembly. Your textures are never uploaded to a server, ensuring complete asset privacy.
14 Standard 2D Block Footprints (4×4 to 12×12)
Full decoding support for all 14 standard 2D ASTC block sizes, from high-quality 4×4 (8.0 bpp) to ultra-compact 12×12 (0.89 bpp).
Instant Canvas Preview
Real-time texture visualization with responsive zoom, pan, and pixel-level inspection.
Color & Alpha Channel Inspection
Isolate RGBA, RGB, or individual R, G, B, and Alpha channels to inspect tangent-space normal maps and masks.
One-Click Export to PNG
Convert decoded .astc textures to standard PNG images directly in your browser with no desktop software needed.
Free & Private
No limits, no account required, powered by high-performance client-side WebAssembly.
How to Use ASTC Decoder
Upload Your ASTC File
Drag and drop your .astc file into the upload box, or click to select a file from your computer.
View Texture Details
The viewer parses texture dimensions, 2D block footprint (e.g. 4×4 to 12×12), and file size upon loading.
Inspect Preview and Channels
Inspect your decoded texture with zoom and pan controls, and switch between RGBA, RGB, or isolated color and alpha channels.
Export to PNG Image
Download the decoded ASTC texture as a standard PNG image for asset review, documentation, or downstream workflows.
Frequently Asked Questions
Yes. This tool functions both as an in-browser ASTC viewer for inspecting .astc files and as a converter to decode ASTC textures and export them to standard PNG images.
You can open and view standard 2D .astc files covering all 14 block footprints (4×4 to 12×12), such as textures extracted from mobile APKs/IPAs or exported by astcenc. Bundled engine archives (e.g. Unity .bundle or Unreal .pak) must be unpacked to raw .astc first.
Yes, absolutely. All ASTC parsing and decoding occurs entirely in your browser using local WebAssembly. Your files are never uploaded to any remote server.
Yes. Technical artists and mobile developers can drag and drop .astc files to inspect RGB channels and isolated Alpha or Green/Red channels, verifying tangent-space normal map vectors and compression artifacts without CLI tools.
The viewer decodes 2D textures to standard RGBA8 for canvas preview and PNG export. It does not provide certified HDR high-fidelity decoding or tone mapping; production HDR workflows should use specialized tools supporting full HDR pipeline output.
The ASTC decoder works in all modern browsers supporting WebAssembly and HTML5 Canvas, including Chrome, Firefox, Safari, and Edge.
Once the web page and WebAssembly decoder module are loaded, the decoding process operates entirely offline in your browser without requiring ongoing internet access.
To convert PNG, JPG, or WebP images into ASTC format, use our online ASTC Encoder tool to encode textures directly in your browser.