Online CRN Converter (Crunch Encoder) - Encode Images to CRN format
Create crunchy textures using our free online CRN converter. Swiftly encode your assets to .crn container files relying on Crunch (BC1/BC3 DXT compressions) minimizing end distribution size.
Related Resources
Step 1: Select Image
- Requirement: width and height must be multiples of 4
HDR input note
HDR, EXR, and UltraHDR JPEG files can be used as inputs. Most current output paths still tone map into the RGBA8 encode pipeline; use DDS BC6H, KTX2 RGBA16F, or KTX2 RGBA32F when you need to preserve HDR source data as much as possible.
Features
Native CRN Output
Powered by crunch wasm to output .crn files directly.
BC1 / BC3 Support
First release supports common BC1 and BC3 encode modes.
Quality Control
Quality level 0-255 to balance visual quality and size.
Browser-side Processing
All encoding runs locally without uploading source images.
Unified Workflow
Same upload/status/download UX as other encode pages.
Round-trip Validation
Encoded files can be verified immediately in CRN decode page.
How to Use
Upload Image
Select PNG/JPG/WebP or other common image formats.
Choose Format
Select BC1 or BC3 based on your target use case.
Set Quality
Adjust quality level in the 0-255 range.
Download Result
Download the generated .crn file when encoding completes.
Frequently Asked Questions
CRN is Crunch's lossy compressed texture container designed for fast transcoding to BC block-compressed data.
Current support includes BC1 and BC3, both emitted as .crn.
BC1/BC3 are 4x4 block-based formats, so non-4x dimensions are blocked in this first release.
Higher quality usually improves image fidelity, but may increase encode time and output size.
No. Encoding is performed locally in your browser via WebAssembly.
Yes. You can load the generated file in the CRN decode page for quick validation.