The EXIF-JPEG metadata structure is similar to JPEG one. But EXIF-JPEG sends the Exif APP1 marker segment data in parsed form and Jfif APP0 marker segment data is not parsed and sent as raw data.

EXIF-JPEG Level

All items between items with Name "EXIF" and Id IG_FORMAT_EXIF_JPEG (Type LEVEL_START and LEVEL_END) are interpreted as EXIF data. If during sending data from application level to filter level the first item is omitted the data will not be interpreted and saved.

For JPEG marker segment levels see JPEG Non-Image Data Structure.

Exif APP1 Marker Segment Level

The "APP1_DATASIZE" item can be omitted during saving.

For more detailed Exif information see EXIF-TIFF Non-Image Data Structure.

EXIF Makernote

Makernote is a standard EXIF tag of UNDEFINED (byte) type. This tag usually is used as a "hidden" IFD. Makernote can not be read in and written out as a BLOB, because IFD offsets become invalid. Therefore, to preserve this tag while writing an image it's necessary to decode it during reading and re-encode it during writing, despite the fact that formally makernote is just a binary tag.

See enumIGEXIFMakerNoteType for descriptions of the various makernote types.

To present Makernote info in a convenient way ImageGear introduces a special structure as an addition to the standard EXIF Metadata: "Makernote*s* Wrapper IFD". Instead of a single binary Makernote*s* tag (37500), we are adding a virtual IFD, containing all the information about Makernote*s*.

'Makernote Wrapper IFD' has the following format depending on the 'type' tag:

'MakerNote wrapper IFD'
-------->'type' = IG_MAKERNOTE_TYPE_UNKNOWN
-------->'binary MakerNote'

Type IG_MAKERNOTE_TYPE_IFD: 
'MakerNote wrapper IFD'
-------->'type' = IG_MAKERNOTE_TYPE_IFD
-------->'MakerNote IFD'
----------------> 'individual MakerNote tag 1'
----------------> 'individual MakerNote tag 2'
...
----------------> 'individual MakerNote tag N'
-------->'binary MakerNote'

Type IG_MAKERNOTE_TYPE_IFD_PREFIXED: 
'MakerNote wrapper IFD'
-------->'type' = IG_MAKERNOTE_TYPE_IFD_PREFIXED
-------->'MakerNote IFD prefix'
-------->'MakerNote IFD'
----------------> 'individual MakerNote tag 1'
----------------> 'individual MakerNote tag 2'
...
----------------> 'individual MakerNote tag N'
-------->'binary MakerNote'

Type IG_MAKERNOTE_TYPE_TIF_HEADER_PREFIXED: 
'MakerNote wrapper IFD' 
-------->'type' = IG_MAKERNOTE_TYPE_TIF_HEADER_PREFIXED
<The rest of the structure is identical to IG_MAKERNOTE_TYPE_IFD_PREFIXED>

Type IG_MAKERNOTE_TYPE_IFD_PREFIXED_OFFSET_II: 
'MakerNote wrapper IFD'
-------->'type' = IG_MAKERNOTE_TYPE_IFD_PREFIXED_OFFSET_II
<The rest of the structure is identical to IG_MAKERNOTE_TYPE_IFD_PREFIXED>

If 'Makernote' EXIF tag is present in the file then ImageGear will always provide it in its original binary form via meta-data callback ('binary Makernote' tag) on the read side, and will also optionally provide it as a decoded sub-IFD (w/ or w/o prefix depending on how it is stored in the original file) if it can be decoded.

ImageGear will ignore 'binary Makernote' tag on the write side for the 'Makernote wrapper IFDs' that have 'type' other than IG_MAKERNOTE_TYPE_UNKNOWN - and construct 'Makernote' EXIF tag based on the 'Makernote IFD'.

ImageGear will store 'binary Makernote' to file 'as is' for the 'Makernote wrapper IFDs' that have 'type' set to IG_MAKERNOTE_TYPE_UNKNOWN.

If 'Makernote wrapper IFD' is not provided to ImageGear during saving operation then 'Makernote' EXIF tag will not be saved into the output file.

Makernote IFD tags are listed below:

Custom Makernote Tags and IFDs

The following custom tags and IFDs are introduced for Makernote support:

Makernote Wrapper IFD: tag = 37500 (same as standard Makernote tag). This IFD is located in the "Exif IFD" (34665).

For information about new tags, which belong to the Makernote Wrapper IFD, see enumIGEXIFMakerNoteTagIDs.

Vendors and Models Currently Supported

Exif APP2 Marker Segment (Flashpix Extensions) Levels

EXIF file format allows you to store Flashpix extensions in APP2 marker segments.

FPXR Contents List APP2 Marker Segment

Interoperability Entity Level

FPXR Data Stream APP2 Marker Segment

*<Ind.> is pointer to appropriate "InteroperabilityEntity" of FPXR Contents List APP2 marker segment. <Ind.> value is between 0 and <n> - 1(<n> is the "FPXRInteroperabilityCount" item value of FPXR Contents List APP2 marker segment).

The Other FPXR APP2 Marker Segment

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