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

The viewer is implemented in WebGL and renders a single textured quad. It also supports encoding .PNG, .JPG, .EXR or .HDR files to LDR or HDR .KTX2 files. 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 12 megapixels or 4 megapixels (depending on format and WASM64/WASM32) to avoid running out of WASM memory.




Use Multithreading (if available)
Additional Worker Threads (Max 18):


.ktx2 file:

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

--Select Image File-- 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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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

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Primary compression quality/effort options:
Use unified quality/effort options (overrides below low-level options):
Effort: 2

Quality: 80

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Transcoder Options (Decode Flags):
ETC1S: No BC7 Chroma Artifact Filtering (faster transcoding):
XUASTC/ASTC LDR: Disable deblocking filtering (faster):
XUASTC/ASTC LDR: Stronger deblocking filtering:
XUASTC/ASTC LDR: Use deblocking on all block sizes (slower):
XUASTC LDR 4x4/6x6/8x6: No direct BC7 transcoding (slower/higher quality):
Prefer higher quality transcoding when supported (slower):

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Display/Visualization Options:


Disabled
Exposure: 1

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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 Quality: 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:

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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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Low-level XUASTC/ASTC LDR 4x4-12x12 Options:
XUASTC LDR Syntax: Full arithmetic (slowest transcoding, highest compression) Hybrid arithmetic+Zstd Full ZStd (fastest transcoding, lowest compression)
Effort Level (higher=slower): 3
XUASTC Weight Grid DCT Quality (100=no DCT): 80
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):

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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Other Options:
Use sRGB/perceptual metrics:
Generate mipmap levels:
Y flip source image:

Debug Output (See Dev Console): Compute Stats (slower encoding):

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Log Output: