Yalantis/uCrop · error · CImgIOException

load_parrec(): Failed to recognize valid PAR-REC data in…

Error message

load_parrec(): Failed to recognize valid PAR-REC data in file '%s'.

What it means

After parsing the PAR header and REC data, load_parrec() checks whether any image dimensions were actually set (_width). A zero width means the parser never recognized valid PAR/REC content, so CImg throws CImgIOException instead of returning an empty list.

Solutions

Pass the .PAR header file (not the .REC binary) to load_parrec()
Open the file in a text editor and confirm it contains Philips PAR header blocks ('# Interested Eco lane', image lines, etc.)
Re-transfer/re-download the study - truncated files parse to zero images
If the format is a newer Philips revision, convert to NIfTI/DICOM externally or update CImg

Example fix

// before
imgs.load_parrec("scan.rec"); // binary data, no PAR header
// after
imgs.load_parrec("scan.par"); // PAR text header (references scan.rec)

Defensive patterns

Strategy: validation

Validate before calling

std::ifstream f(parPath); std::string line;
bool isPar = false;
while (std::getline(f, line)) if (line.rfind("# ", 0) == 0 && line.find("Philips") != std::string::npos) { isPar = true; break; }
if (!isPar) { /* not a PAR header - abort or convert */ }

Try / catch

try { imgs.load_parrec(parPath); }
catch (CImgIOException& e) { fprintf(stderr, "not a valid PAR file: %s\n", e.what()); }

Prevention

Always pass the .par header, never the .rec binary
Check the file's first lines look like a Philips PAR header before loading
Verify file sizes after transfer (truncation detection)

When it happens

Trigger: load_parrec() given a file that lacks the required PAR header keywords (e.g. '# Patients', '# Recon resolution', image info lines) so no image records are parsed; passing the .REC file instead of the .PAR text header; an empty or wrong-format file.

Common situations: Mixing up the .par and .rec files (the loader wants the .par header path); loading a renamed DICOM/NIfTI file with a .par extension; truncated downloads; PAR files from scanner versions with a header layout CImg cannot parse.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/958ebde39d6ecee5. Report an issue: GitHub.

Appendix: source

Thrown at ucrop/src/main/jni/CImg.h:67124

          CImg<uintT> buf(size_x,size_y);
          cimg::fread(buf._data,size_x*size_y,file2);
          if (cimg::endianness()) cimg::invert_endianness(buf._data,size_x*size_y);
          CImg<T>& img = (*this)[imn];
          cimg_forXY(img,x,y) img(x,y,sn) = (T)(( buf(x,y)*rs + ri )/(rs*ss));
        } break;
        default :
          cimg::fclose(file);
          cimg::fclose(file2);
          throw CImgIOException(_cimglist_instance
                                "load_parrec(): Unsupported %d-bits pixel type for file '%s'.",
                                cimglist_instance,
                                pixsize,filename);
        }
      }
      cimg::fclose(file);
      cimg::fclose(file2);
      if (!_width)
        throw CImgIOException(_cimglist_instance
                              "load_parrec(): Failed to recognize valid PAR-REC data in file '%s'.",
                              cimglist_instance,
                              filename);
      return *this;
    }

    //! Load a list from a PAR/REC (Philips) file \newinstance.
    static CImgList<T> get_load_parrec(const char *const filename) {
      return CImgList<T>().load_parrec(filename);
    }

    //! Load a list from a YUV image sequence file.
    /**
        \param filename Filename to read data from.
        \param size_x Width of the images.
        \param size_y Height of the images.
        \param chroma_subsampling Type of chroma subsampling. Can be <tt>{ 420 | 422 | 444 }</tt>.
        \param first_frame Index of first image frame to read.

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