BabylonJS/Babylon.js · error · Error

Wrong hufUncompress

Error message

Wrong hufUncompress

What it means

After unpacking the Huffman encoding table, HufUncompress checks that the declared bit count (nBits) does not exceed the remaining compressed bytes (×8). If it does, the stream claims more payload bits than physically exist, so the data is incomplete/invalid and decoding is refused before HufDecode runs.

Source

Thrown at packages/dev/core/src/Materials/Textures/Loaders/EXR/exrLoader.compression.huf.ts:453

    const nBits = ParseUint32(dataView, offset);

    offset.value += 4;

    if (im < 0 || im >= HUF_ENCSIZE || iM < 0 || iM >= HUF_ENCSIZE) {
        throw new Error("Wrong HUF_ENCSIZE");
    }

    const freq = new Array(HUF_ENCSIZE);
    const hdec = new Array(HUF_DECSIZE);

    HufClearDecTable(hdec);

    const ni = nCompressed - (offset.value - initialInOffset);

    HufUnpackEncTable(array, offset, ni, im, iM, freq);

    if (nBits > 8 * (nCompressed - (offset.value - initialInOffset))) {
        throw new Error("Wrong hufUncompress");
    }

    HufBuildDecTable(freq, im, iM, hdec);

    HufDecode(freq, hdec, array, offset, nBits, iM, nRaw, outBuffer, outOffset);
}

function UInt16(value: number) {
    return value & 0xffff;
}

function Int16(value: number) {
    const ref = UInt16(value);
    return ref > 0x7fff ? ref - 0x10000 : ref;
}

function Wdec14(l: number, h: number) {
    const ls = Int16(l);

View on GitHub (pinned to 0592b347b8)

Solutions

1. Re-download the .exr and confirm it is not truncated
2. Verify the chunk's data size and offset come from the file's scanline offset table, not a hard-coded value
3. Confirm the file decompresses in a reference EXR tool
4. Re-export with a non-PIZ compression to rule out a writer bug

if (expectedByteLength && file.byteLength !== expectedByteLength) throw new Error("EXR truncated: got " + file.byteLength + " expected " + expectedByteLength);

try {
  await loader.loadAsync(blob);
} catch (e) {
  if (/Wrong hufUncompress/.test(String(e))) {
    // nBits exceeds remaining bytes → truncated block; re-fetch or use fallback asset
    return loadFallbackTexture(url);
  }
  throw e;
}

When it happens

Trigger: Raised in HufUncompress (called by UncompressPIZ) when nCompressed was too small — typically the scanline block size/offset used to slice the huf data was wrong or the block was truncated.

Common situations: Truncated HTTP responses, incorrectly computed nCompressed when manually reading EXR chunk data, or a corrupt offset table pointing mid-block.

Related errors

• Error in HufUnpackEncTable
• Wrong HUF_ENCSIZE
• Wrong PIZ_COMPRESSION BITMAP_SIZE
• Invalid table entry
• hufDecode issues

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/84b0970651e7b782. Report an issue: GitHub.