Yalantis/uCrop · error · CImgIOException

load_jxl(): Failed to decode image '%s'.

Error message

load_jxl(): Failed to decode image '%s'.

What it means

During the JxlDecoderProcessInput loop, status JXL_DEC_ERROR or JXL_DEC_NEED_MORE_INPUT means the bitstream could not be decoded (or was incomplete), so CImg destroys the decoder and throws. This is the generic 'not valid / corrupt JPEG XL data' failure.

Source

Thrown at ucrop/src/main/jni/CImg.h:57179

                              "load_jxl(): Failed to configure decoder '%s'.",
                              cimg_instance,
                              nfilename);
      }
      if (JXL_DEC_SUCCESS!=JxlDecoderSetInput(decoder,buffer._data,buffer._width)) {
        JxlDecoderDestroy(decoder);
        throw CImgIOException(_cimg_instance
                              "load_jxl(): Failed to load image data '%s'.",
                              cimg_instance,
                              nfilename);
      }
      JxlDecoderCloseInput(decoder);

      while (true) {
        JxlDecoderStatus status = JxlDecoderProcessInput(decoder);
        if (status==JXL_DEC_SUCCESS || status==JXL_DEC_FULL_IMAGE) break;
        else if (status==JXL_DEC_ERROR || status==JXL_DEC_NEED_MORE_INPUT) {
          JxlDecoderDestroy(decoder);
          throw CImgIOException(_cimg_instance
                                "load_jxl(): Failed to decode image '%s'.",
                                cimg_instance,
                                nfilename);
        } else if (status==JXL_DEC_BASIC_INFO) {
          if (JXL_DEC_SUCCESS!=JxlDecoderGetBasicInfo(decoder,&jxlInfo)) {
            JxlDecoderDestroy(decoder);
            throw CImgIOException(_cimg_instance
                                  "load_jxl(): Failed to load image data '%s'.",
                                  cimg_instance,
                                  nfilename);
          }
          if (jxlInfo.have_animation!=0) {
            JxlDecoderDestroy(decoder);
            throw CImgIOException(_cimg_instance
                                  "load_jxl(): Does not support animated JPEG XL '%s'.",
                                  cimg_instance,
                                  nfilename);
          }

View on GitHub (pinned to f788b534b4)

Solutions

1. Validate the file is a genuine JPEG XL image (check FF 0A signature or JXL container box) before loading.
2. Re-obtain a complete, untruncated copy of the file (verify size/checksum).
3. If the image may not be JXL, sniff the format first (cimg::file_type) and dispatch to the appropriate load_* function.
4. For NEED_MORE_INPUT caused by non-standard containers, decode with libjxl's cjxl/djxl-compatible reference setup or convert the file.

Example fix

// before
img.load_jxl(userFile); // corrupt/renamed file throws
// after
if (cimg::file_type(userFile) != "jxl") { /* route to load_jpeg etc. */ }
else img.load_jxl(userFile);

bool looksLikeJxl(const unsigned char* d, size_t n) {
  if (n < 2) return false;
  if (d[0] == 0xFF && d[1] == 0x0A) return true; // codestream
  return n >= 12 && std::memcmp(d, "\x00\x00\x00\x0CJXL ", 8) == 0; // container
}

try { img.load_jxl(path); } catch (CImgIOException& e) { log("not valid jxl, falling back to sniffed loader"); img.load(path); }

When it happens

Trigger: JxlDecoderProcessInput returns JXL_DEC_ERROR or JXL_DEC_NEED_MORE_INPUT inside load_jxl()'s decode loop, typically because the file is not a valid JXL codestream/container or is truncated.

Common situations: Renaming a JPEG/PNG to .jxl and feeding it to load_jxl, partially downloaded files, or ISOBMFF container with data CImg's simple single-pass loop does not supply (NEED_MORE_INPUT).

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• load_jxl(): Failed to decode image data '%s'.
• load_jxl(): Failed to set decode buffer '%s'.
• load_bmp(): Invalid offset %d specified in filename '%s'.
• load_bmp(): File size %lu for filename '%s' does not match e
• load_bmp(): Malformed header in filename '%s'.

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/e1dbb46d4507f5fc. Report an issue: GitHub.