This tool uses the Basis Universal C++ transcoder (compiled to WebAssembly using Emscripten) to transcode a .ktx2 file to:
FORMAT

About Basis Universal .KTX2/.DDS Studio

The viewer is implemented in WebGL and renders a single textured quad. It also supports encoding .PNG, .JPG, .QOI, .EXR or .HDR files to LDR or HDR .KTX2 files.

Additional image formats (.WebP, .AVIF, .GIF, .BMP, .TIFF, .HEIC, .HEIF, .JXL) are supported via browser-assisted decoding (browser support varies by format).

Thanks to Evan Parker for providing webgl-texture-utils and this test bed. Go back.

Notes: Enable your browser debug console (F12 on Chrome/Firefox) to see debug output. The largest image resolution that can be compressed in the browser with this library is limited to either 16 megapixels or 4 megapixels (depending on format and WASM64/WASM32) to avoid running out of WASM memory.

Close

Use Multithreading (if available)
Additional Worker Threads (Max 32):

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Source Image / File Input:

.ktx2 file:

.png/.jpg/.webp/.exr/.hdr file:

--Select Example Image-- desk.exr MtTamWest.exr sponza.exr CandleGlass.exr src_atrium.exr src_backyard.exr src_memorial.exr src_yucca.exr Tree.exr kodim18_512x512.png kodim18_64x64.png kodim01.png kodim02.png kodim03.png kodim04.png kodim05.png kodim06.png kodim07.png kodim08.png kodim09.png kodim10.png kodim11.png kodim12.png kodim13.png kodim14.png kodim15.png kodim16.png kodim17.png kodim18.png kodim19.png kodim20.png kodim21.png kodim22.png kodim23.png kodim24.png kodim25.png kodim26.png xmen.png tng.png base.png

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Encoding Settings Preset: sRGB Photo (default) Linear Texture / Normal Map

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KTX2 Texture Format to Encode: ETC1S UASTC LDR 4x4 UASTC HDR 4x4 RDO ASTC HDR 6x6 UASTC HDR 6x6 Intermediate XUASTC LDR 4x4 XUASTC LDR 5x4 XUASTC LDR 5x5 XUASTC LDR 6x5 XUASTC LDR 6x6 XUASTC LDR 8x5 XUASTC LDR 8x6 XUASTC LDR 10x5 XUASTC LDR 10x6 XUASTC LDR 8x8 XUASTC LDR 10x8 XUASTC LDR 10x10 XUASTC LDR 12x10 XUASTC LDR 12x12 ASTC LDR 4x4 ASTC LDR 5x4 ASTC LDR 5x5 ASTC LDR 6x5 ASTC LDR 6x6 ASTC LDR 8x5 ASTC LDR 8x6 ASTC LDR 10x5 ASTC LDR 10x6 ASTC LDR 8x8 ASTC LDR 10x8 ASTC LDR 10x10 ASTC LDR 12x10 ASTC LDR 12x12 XUBC7

XUASTC LDR Syntax: Full arithmetic (slowest transcoding, highest compression) Hybrid arithmetic+Zstd Full ZStd (fastest transcoding, lowest compression)

XUBC7 RDO Level (higher=smaller): 0

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Primary compression quality/effort options:
Use unified quality/effort options (overrides many below low-level options):
Effort: 3

Quality: 80

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Display/Visualization Options:


Disabled
Exposure: 1.0000
Display Zoom: 1x
Mipmap Level: 0
Cubemap Face: 0
Array Layer: 0
Canvas Bilinear Filtering:
Canvas Color Space: Default (browser) sRGB Display P3
XUASTC/ASTC LDR: Visualize GPU deblocking edge weights:

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Transcoder Options (Decode Flags):
Deblocking Filter Mode: Disabled Auto: Use file's FilterID - GPU if enabled by texture file, otherwise disabled Force GPU deblocking on >=10x8 blocks, ignore file FilterID Force CPU deblocking on >=10x8 blocks, ignore file FilterID (if available for tex fmt)
Apply deblocking filter to all block sizes when forced, not just to large block sizes:
ETC1S: No BC7 Chroma Artifact Filtering (faster transcoding):
XUASTC LDR 4x4/6x6/8x6: No direct BC7 transcoding (slower/higher quality):
Prefer higher quality transcoding when supported (slower):
Transcode alpha to opaque (ETC1/PVRTC1_RGB):

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Mipmap Generation Options

Generate mipmap levels:
Mip Filter: box tent bell b-spline mitchell blackman lanczos3 lanczos4 lanczos6 lanczos12 kaiser gaussian catmullrom quadratic_interp quadratic_approx quadratic_mix
Mip Scale:
Smallest Mip Dimension:
Mip Wrapping: Mip Renormalize:

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.DDS/.KTX Developer Tools

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Export encoded .KTX2 to .DDS: BC1 (RGB) BC3 (RGBA) BC4 (R) BC5 (RG) BC6H (HDR RGB) BC7 (RGBA) RGBA32 (uncompressed)

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Export encoded .KTX2 to .KTX (v1): BC1 (RGB) BC3 (RGBA) BC4 (R) BC5 (RG) BC6H (HDR RGB) BC7 (RGBA) ETC1 (RGB) ETC2 (RGBA) EAC R11 EAC RG11 PVRTC1 4bpp RGB PVRTC1 4bpp RGBA PVRTC2 4bpp RGB PVRTC2 4bpp RGBA ASTC LDR 4x4 ASTC LDR 5x4 ASTC LDR 5x5 ASTC LDR 6x5 ASTC LDR 6x6 ASTC LDR 8x5 ASTC LDR 8x6 ASTC LDR 10x5 ASTC LDR 10x6 ASTC LDR 8x8 ASTC LDR 10x8 ASTC LDR 10x10 ASTC LDR 12x10 ASTC LDR 12x12 ASTC HDR 4x4 ASTC HDR 6x6

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Encode loaded source image directly to .DDS:
Download encoded .DDS file when done
DDS Texture Format to Encode: BC1 BC2 BC3 BC4 (R) BC5 (RG) BC7 A8R8G8B8 (BGRA) A8B8G8R8 (RGBA) R8 R8G8 R5G6B5 A1R5G5B5 A4R4G4B4

BC7 Encoder: bc7f (fast, default) bc7e_scalar (slower, higher quality)

bc7f options: analytical partial non-analytical

bc7e_scalar level: 0 1 2 3 4 5 6

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Low-level XUASTC/ASTC LDR 4x4-12x12 Options

Effort Level (higher=slower): 2
XUASTC Weight Grid DCT Quality (100=no DCT): 80

Global Optimization (SCD)/Deblocking (FilterID stored in file): Disabled (no SCD, no filtering) Auto: Use SCD+filtering only on largest (>=10x8) block sizes Enable SCD+filtering on all block sizes Enable SCD, disable filtering Disable SCD, enable filtering on largest block sizes Disable SCD, enable filtering on all block sizes
Deblocking Passes (2-255, 256=auto depending on effort): 256

Bounded/windowed RDO lossy supercompression:
No RGB dual plane (lower quality, faster encoding/BC7 transcoding):
No 2-3 subset usage (lower quality, faster encoding/BC7 transcoding):
Enable prefiltering/blurred candidates (higher quality, slower):
Heavy subset usage (higher quality at lowest bitrates, slower):

LDR Compressor: Auto (tied to effort): ASTCF or merge basisu+ASTCF Use basisu's original ASTC encoder Use ASTCENC Use ASTCF Merge basisu+ASTCENC Merge basisu+ASTCF Merge All

Sharpening Mode: Disabled Auto: On 10x8 or larger block sizes All block sizes
Sharpening Strength:

ASTC/XUASTC LDR Bounded/Windowed RDO Params:
Opaque:
Min Acceptable PSNR:
Window Size (Simple) PSNR:
Window Size (Edge) PSNR:

Alpha:
Min Acceptable Alpha PSNR:
Window Size (Simple) Alpha PSNR:
Window Size (Edge) Alpha Edge PSNR:

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Low-level XUBC7 Options

Number of Stripes (1-16, more=faster encode/decode, slightly larger): 8

BC7 Base Encoder: bc7f (fast, default) bc7e_scalar (slower, higher quality)

bc7e_scalar Level (0-6, higher=slower/better; only used when bc7e_scalar selected): 2

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Low-level ETC1S LDR Options

ETC1S Quality: 255
Effort Level: 1

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Low-level UASTC LDR 4x4 Options

UASTC LDR RDO: RDO Quality: 1.0
UASTC LDR Effort: 1

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Low-level UASTC HDR 4x4 Options

UASTC HDR Effort: 0

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Low-level ASTC/UASTC HDR 6x6 Options

Effort Level: 0
RDO Quality (Lambda, 0-50k, try 0-5k, higher=smaller):
REC 2020 Colorspace (impacts error metrics, KTX2 DFD Gamut):

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LDR->HDR Upconversion Options

Convert LDR images to linear light:
LDR to HDR Upconversion Nit Multiplier: Invalid value!

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Other Options:
Image is sRGB/use sRGB perceptual metrics:
Y flip source image:

Channel Weights (XUASTC/ASTC/XUBC7/DDS bc7e_scalar):
R: G: B: A:

Channel Swizzle (each output channel's source index 0-3; default 0,1,2,3 = no swizzle):
R: G: B: A:

Debug Output (See Dev Console):
Clear Dev Console on each encode:
Encode on worker thread by default (on image load):
Auto-close encode progress dialog when done (uncheck to study debug output):
Compute Stats (slower encoding):
Print Stats:

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Development Log Output Clear

Encoding…

Automatically close when done Close