File Formats: JPEG and LEAD Compressed (JPG, J2K, JP2, JPM, JLS, CMP, and CMW)

LEADTOOLS reads and writes the following LEAD and JPEG compressed formats:

• LEAD. This is the LEAD CMP compressed format for grayscale and color images. This format results in smaller files and better image quality than industry-standard formats. In addition, LEAD also supports CMW files, which use Wavelet CMP compression in 8, 12, and 16-bit grayscale and 24-bit color. (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

• Progressive LEAD. This is a LEAD format that is useful for transmitting images, because the first part of the file contains the full dimensions of the image. Therefore, in a paint-while-load routine, you can display the whole image, then progressively clarify it as the rest of the file loads. In this format you can read and write 8 or 24 bits per pixel, where 8 is for grayscale and 24 is for color.

• Lossy JFIF. This is the JPEG File Interchange Format. LEADTOOLS supports YUV 4:4:4, 4:2:2, and 4:1:1 color spacing, and YUV 4:0:0 for grayscale.

• Lossless JFIF. This is the JPEG File Interchange Format. LEADTOOLS supports 8, 12, and 16-bit grayscale and 24-bit color spacing. Please note that not all applications support Lossless JPEG. Before saving a file using Lossless JPEG, make sure your reader supports it.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

Both JPEG 4:4:4 and Lossless JPEG will be recognized when getting file information.

NOTE: JFIF  4:1:1 and 4:2:2 formats use subsampling for the color components. In the case of 411, the color components for 4 pixels is averaged during compression. This will cause a color shift, but the shift is tolerable for low compression ratios. If you have high compression and repeated savings, then the color shift will increase.  Due to inherent limitations of the JPEG algorithm, the only ways to avoid this are: (a) avoid repeated load and resave, or (b) use 4:4:4  format, which has no subsampling.

• Progressive JPEG. This is a JFIF format that is useful for transmitting images, because the first part of the file contains the full dimensions of the image. Therefore, in a paint-while-load routine, you can display the whole image, then progressively clarify it as the rest of the file loads. LEADTOOLS supports YUV 4:4:4, 4:2:2, and 4:1:1 color spacing, and YUV 4:0:0 for grayscale.

• Lossy JTIF. This is the JPEG Tagged Interchange Format. LEADTOOLS supports YUV 4:4:4, 4:2:2, and 4:1:1 color spacing, and YUV 4:0:0 for grayscale.

• Lossless JTIF. This is the JPEG Tagged Interchange Format. LEADTOOLS supports 8, 12, and 16-bit grayscale and 24-bit color spacing. Please note that not all applications support Lossless JPEG. Before saving a file using Lossless JPEG, make sure your reader supports it.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

Both TIFF JPEG 4:4:4 and Lossless JPEG will be recognized when getting file information.

• J2K - Lossy or Lossless. This is a JPEG 2000 format. LEADTOOLS can read  8, 12, and 16-bit grayscale and 24, 32, 48 and 64--bit color images. The J2K format contains only a stream of image data.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

• JP2 - Lossy or Lossless. This is a JPEG 2000 format. LEADTOOLS can read  8, 12, and 16-bit grayscale and 24, 32, 48 and 64-bit color images. The JP2 format contains a stream of image data, plus extra data about the organization and contents of the file.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

• JPX (JPEG 2000 Part 2) - This JPEG 2000 format is especially useful for document, medical, and satellite imagery archiving systems. All LEADTOOLS Imaging Pro, Document Imaging, and Medical Imaging toolkits can read/parse JPX files.  LEADTOOLS Document and Medical Imaging toolkits also add support for writing JPX files and manipulating JPX boxes, frames, GML Data, and other advanced JPX features. For more information, refer to File Formats: JPX.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

• JPM (JPEG 2000 Part 6) - This JPEG 2000 compound image format is developed by the Joint Photographic Experts Group (JPEG). It is especially useful for document, pre-press, and fax-like images. It contains layered still images that use FAX (Group 3-1D, Group 3-2D, Group 4), JBIG1, JBIG2, JPEG Lossy, JPEG Lossless and J2K encodings. JPM file format inherits features from its parent JP2, JPEG 2000 Part 1 (Core). This file format supports stamps, but does not support QFactor, progressive loading or Sub-formats. LEAD supports loading multi-page files in this format. For more information, refer to http://www.digitalpreservation.gov/formats/fdd/fdd000144.shtml.

• JLS - JPEG-LS Lossless and Near Lossless. This raster image format is developed by the Joint Photographic Experts Group (JPEG). JPEG-LS algorithm is based on LOCO-l (low complexity lossless compression for images). LEAD supports compress and decompress lossless and near lossless images. JPEG-LS has popularity in medical imaging and used within DICOM standard.   JLS Filter supports loading and saving 8, 12 and 16 BPP grayscale images, it supports three modes of 24-bit (RGB)  for loading and saving; Non-interleaved, line-interleaved, or sample-interleaved. This file format supports QFactor. Possible values can be a value between 2 and 255 (lossy compression), or value 0 (lossless compression). This file format does not support stamps, progressive loading/saving, Sub-formats, or loading/saving multi-page files. For more information, refer to http://www.hpl.hp.com/loco/ and http://www.itu.int/rec/T-REC-T.87/en. JLS read/write (save) support is included with toolkits.  

• TIF J2K - Lossy or Lossless. This is a Tagged Image File with JPEG 2000 Compression. This file format contains only a stream of image data. LEADTOOLS supports reading  8, 12, and 16-bit grayscale 24, 32, 48 and 64-bit color spacing. All LEADTOOLS SDKs read J2K files. J2K write (save) support is included with toolkits.  (12 and 16-bit grayscale images are only supported in the Document and Medical Imaging toolkits.)

For general information, refer to Compression Using LEAD and JPEG Formats. For instructions for implementing progressive formats, refer to Controlling Progressive Loads and Saves. JPEG and LEAD files can contain many comment fields of various types. You can use the L_ReadFileComment function to read comments in an existing file. Before writing a file, you can use the L_SetComment function to create an array of comments to be saved in the file. You can use the L_DeleteComment function to delete a comment field from a file.

Please note that the LTCLR DLL is required for loading JPEG CMYK images and for loading and saving JPEG LAB images.

File constants associated with this file format are as follows:

Required DLL: For a listing of the exact DLLs needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Related Formats: JPX - JPX Format, EXIF - Exif Formats, FPX - Kodak Format, TIFF - Tagged Image File Format.

Platforms

Win32, x64.

See Also:

Compression Using LEAD and JPEG Formats

Introduction: Bitmaps in Memory and in Files

Programming with JPEG 2000 Features

Programming with JPX Features

Raster Image Functions: Working with JPEG 2000

Raster Image Functions: Working with JPX

JPEG and LEAD File Comments

JPEG 2000 File Comments

JPX File Comments