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HEIF (HEIC)

The High Efficiency File Format (HEIF) is described in ISO/IEC 23008-12. This format is common on the latest iPhone and iPad devices using iOS 11 or later. Some digital cameras (eg: Canon) support this format as well.

Compression

The HEIF file format standard specifies that the images can be compressed using HEVC (H265), AVC (H264) or JPEG compression. But in reality, nobody really uses H264 or JPEG compression with this file format. Everybody uses HEVC (H265) compression.

The HEIF files with HEVC (H265) compression use the extension ".heic". Also, by convention, HEIF files with HEVC compression are called HEIC files.

Curretly, LEADTOOLS supports only the HEVC compression.

Features

Thumbnails (Stamps). Use L_ReadFileStamp2 to read a thumbnail. You can save a stamp by setting the ESO_SAVEWITHSTAMP flag in the SAVEFILEOPTION.Flags structure member prior to calling the save function.
Exif metadata, which can contain all the comments and tags supported by TIFF and EXIF. HEIC files can contain an embedded TIF file that contains only tags and comments information (no image data). So any metadata that can be saved in TIFF/Exif files can be saved in HEIC as well.
- Use the L_ReadFileComment or L_ReadFileComments function to read comments from an existing file. Before writing a file, use the L_SetComment function to create an array of comments to be saved in the file. See the Exif File Comments for the list of comments supported.
- Use L_ReadFileTag2 to read TIFF/Exif tags from an existing HEIC file. Use L_SetTag before calling the save function to add your own custom tags to the output file.
8-bit and 10-bit components. HEIC files will typically have 3 x 8-bit color components, which means they are loaded and saved as 24-bit. But the format also supports 10-bit components, and these files are loaded as 48-bit by default. LEADTOOLS will save only 8-bit components (24-bit).
Alpha channel/transparency information. HEIC files can contain optional transparency information from an alpha plane or mask. These files are loaded as 32-bit (if they use 8-bit components) or 64-bit (if they use 10-bit components). For these files, alpha of 0 represents transparent pixels, 255 represents opaque pixels and alpha of 1-254 values represent translucent pixels. LEADTOOLS is currently only loading the alpha information.
Rotate/Flip/Reverse transformation. You can perform a lossless rotate/flip/reverse transformation of an existing file using L_TransformFile, the same way as for CMP, JPEG and TIFF images.

Some places refer to this file format as HEIF, while others as HEIC. Since they represent almost the same thing, for the remainder of this topic, we will refer to everything as HEIC.

File constants associated with this file format are: