Summary
Description:
I would like to propose adding native import support for JPEG XL (.jxl) as a primary texture source format within Unreal Engine. While Oodle Texture is exceptional for runtime and packaged compression, current industry-standard source formats (PNG, TGA, EXR) cause massive storage bloat in Editor-side project folders and Source Control (Git/Perforce) repositories.
The Problem:
Modern high-fidelity projects utilizing 4K/8K textures and 16-bit data (Heightmaps, Displacement, and Mask maps) face exponential growth in the Content folder size:
- PNG / TIFF: Extremely large file sizes for 16-bit data, even with lossless compression.
- EXR: Heavily used for HDR/16-bit float, but introduces significant storage overhead.
- TGA: Completely uncompressed, leading to wasted disk I/O and repository bloating.
- JPEG: Limited to 8-bit depth per channel, making it completely unusable for high-quality 16-bit master source authoring as it causes severe banding artifacts.
The Proposed Solution:
Integrating the open-source libjxl decoder into the Unreal Engine asset pipeline would yield immense benefits:
- Source Storage Efficiency: JXL delivers significantly better compression than PNG/EXR, reducing file sizes by 50-80% in pure lossless mode, and up to 90%+ in visually lossless modes. This directly reduces the Source Data payload size inside .uasset files on the disk.
- 16-bit & HDR Excellence: JXL natively and efficiently supports high bit-depth and alpha channels losslessly, making it the ultimate “master” format for production.
- Faster Workflow: Smaller repository sizes mean faster sync/clone times in Source Control and reduced disk I/O bottlenecks during asset discovery.
Clarification on GPU Cooking:
To clarify, this request is not asking the GPU to render JXL directly. I am fully aware that during the Cooking/Packaging process, textures are re-encoded into GPU-friendly block compression formats (BC7, ASTC, etc.). This feature request specifically targets the Source Data layer in the Editor to solve a major workflow and storage pain point for developers.
What Type of Bug are you experiencing?
Editor
Steps to Reproduce
- Create a texture or heightmap in JPEG XL (.jxl) format.
- Open the Unreal Engine Editor.
- Attempt to drag and drop or import the .jxl file into the Content Browser.
- Observe that the engine does not recognize the file format and cannot import it.
Expected Result
The Unreal Engine Editor should successfully recognize the JPEG XL (.jxl) file format and import it as a standard Texture Asset (UTexture2D) in the Content Browser, efficiently storing its lossless 16-bit or compressed source data.
Observed Result
The editor completely fails to recognize the .jxl file extension. An error message appears stating that the file format is unknown, or the drag-and-drop action is rejected, making it impossible to import JPEG XL assets.
Affects Versions
5.8
Platform(s)
Windows