Brief information on JPEG metadata levels is provided in the set of tables below:
JPEG Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "JPEG-JFIF" |
IG_FORMAT_JPG |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| JPEG marker segment levels |
| "JPEG-JFIF" |
IG_FORMAT_JPG |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
All items between items with Name "JPEG-JFIF" and Id IG_FORMAT_JPG (Type LEVEL_START and LEVEL_END) are interpreted as JPEG metadata. If during sending data from application level to filter level the first item is omitted the data will not be parsed and saved.
JPEG Marker Segment Levels
The following JPEG marker segments metadata are supported:
- Frame marker segment level - SOF0, SOF1, SOF2 and SOF3 (read only),
- Scan marker segment level - SOS (read only),
- Define-quantization-table marker segment level - DQT (read only),
- Define-Huffman-tables marker segment level - DHT (read only),
- Comment marker segment level - COM (read/write),
- Application marker segment level - APP0-APP15 (read/write).
Frame Marker Segment Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| <Frame marker name> |
<Frame marker Id> |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| <Frame marker size tag name> |
<Frame marker size tag Id> |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "Precision" |
212 |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "Lines" |
213 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "SamplesPerLine" |
214 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "ComponentNumber" |
215 |
VALUE_ITEM |
UINT8 |
<n> |
1 |
TRUE |
| Frame component level 1 |
| |
|
| Frame component level <n> |
| <Frame marker name> |
<Frame marker Id> |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
<Frame marker Id>, <Frame marker name>, <Frame marker size tag name> and <Frame marker size tag Id> are described in the table below:
| Frame Marker |
<Frame marker name> |
<Frame marker Id> |
<Frame marker size tag name> |
<Frame marker size tag Id> |
| SOF0 |
"SOF0" |
0xFFC0 |
"SOF0_DATASIZE" |
60192 |
| SOF1 |
"SOF1" |
0xFFC1 |
"SOF1_DATASIZE" |
60193 |
| SOF2 |
"SOF2" |
0xFFC2 |
"SOF2_DATASIZE" |
60194 |
| SOF3 |
"SOF3" |
0xFFC3 |
"SOF3_DATASIZE" |
60195 |
Frame Component Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "Component" |
<Component No.> |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "Id" |
<Component No.> |
VALUE_ITEM |
UINT |
|
1 |
TRUE |
| "MCU_HV" |
<Component No.> |
VALUE_ITEM |
UINT |
|
1 |
TRUE |
| "QuantizationNumber" |
<Component No.> |
VALUE_ITEM |
UINT |
|
1 |
TRUE |
| "Component" |
<Component No.> |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
 |
<Component No.> is frame component identifier of appropriate component. |
Scan Marker Segment Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "SOS" |
0xFFDA |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "SOS_DATASIZE" |
60218 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "ComponentNumber" |
228 |
VALUE_ITEM |
UINT8 |
<n> |
1 |
TRUE |
| Scan component level 1 |
| |
|
| Scan component level <n> |
| "SpectralStart" |
235 |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "SpectralEnd" |
236 |
VALUE_ITEM |
UINT8 |
|
|
TRUE |
| "AH_AL" |
237 |
VALUE_ITEM |
UINT8 |
|
|
TRUE |
| "SOS" |
0xFFDA |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
Scan Component Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "Component" |
<Component No.> |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "Selector" |
<Component No.> |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "DC_AC" |
<Component No.> |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "Component" |
<Component No.> |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
|
<Component No.> is scan component selector of appropriate component. |
Define-Quantization-Table Marker Segment Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "DQT" |
0xFFDB |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "DQT_DATASIZE" |
60219 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "QuantizationTable" |
<table 1 Id> |
VALUE_ITEM |
UINT8 or UINT16 |
|
64 |
TRUE |
| |
| "QuantizationTable" |
<table 1 Id> |
VALUE_ITEM |
UINT8 or UINT16 |
|
64 |
TRUE |
| "DQT" |
0xFFDB |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
|
<table Id> is the appropriate quantization table identifier. |
Define-Huffman-Tables Marker Segment Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "DHT" |
0xFFC4 |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "DHT_DATASIZE" |
60196 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "DATA" |
0xFFC4 |
VALUE_ITEM |
RAW_DATA |
|
<ValueSize> |
TRUE |
| "DHT" |
0xFFC4 |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
Comment Marker Segment Level
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "COM" |
0xFFFE |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "COM_DATASIZE" |
60254 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "Comment" |
0xFFFE |
VALUE_ITEM |
STRING |
|
<ValueSize> |
TRUE |
| "COM" |
0xFFFE |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
Application Marker Segment Level
There are several application marker segments, which data structure is well known. These segments are parsed and their data are passed in special format.
These marker segments are:
- JFIF APP0 segment
- JFIF extension (JFXX) APP0 segment (read only)
- EXIF APP1 segment
- Photoshop Image Resource APP13 marker segment (it includes some IPTC data and another Photoshop Image Resource metadata structure)
- Other application marker segment levels
JFIF APP0 Segment
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "APP0" |
0xFFE0 |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "APP0_DATASIZE" |
60224 |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "JFIF_HEADER" |
200 |
VALUE_ITEM |
STRING |
JFIF |
5 |
TRUE |
| "Version" |
201 |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "ResolutionUnits" |
202 |
VALUE_ITEM |
UINT8 |
|
1 |
FALSE |
| "ResolutionX" |
203 |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "ResolutionY" |
204 |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "ThumbnailWidth" |
205 |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "ThumbnailHeight" |
206 |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "APP0" |
0xFFE0 |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
|
The thumbnail width tags are present only if the thumbnail is stored to JFIF segment.
The thumbnail height tags are present only if the thumbnail is stored to JFIF segment.
|
JFIF Extension (JFXX) APP0 Segment
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "APP0" |
0xFFE0 |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "APP0_DATASIZE" |
60224 |
VALUE_ITEM |
UINT16 |
|
1 |
TRUE |
| "JFIF_EX_HEADER" |
209 |
VALUE_ITEM |
STRING |
"JFXX" |
5 |
TRUE |
| "ExtensionCode" |
210 |
VALUE_ITEM |
UINT8 |
|
1 |
TRUE |
| "APP0" |
0xFFE0 |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
Photoshop Image Resource APP13 Marker Segment
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| "APP13" |
0xFFED |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| "APP13_DATASIZE" |
60237 |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "PHOTOSHOP_HEADER" |
59915 |
VALUE_ITEM |
STRING |
"Photoshop 3.0" |
14 |
FALSE |
| Photoshop Image Resource level 1 |
| ... |
| Photoshop Image Resource level n |
| "APP13" |
0xFFED |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
|
For "Photoshop Image Resource" metadata structure see in TIFF non-image data the Photoshop Image Resource metadata structure table. |
Other Application Marker Segment Levels
| Name |
Id |
Type |
Value Type |
Value |
Value Length |
Read Only |
| <Marker name> |
<Marker Id> |
LEVEL_START |
0 |
NULL |
0 |
TRUE |
| <Marker size tag name> |
<Marker size tag Id> |
VALUE_ITEM |
UINT16 |
|
1 |
FALSE |
| "DATA" |
<Marker Id> |
VALUE_ITEM |
RAW_DATA |
|
<ValueSize> |
FALSE |
| <Marker name> |
<Marker Id> |
LEVEL_END |
0 |
NULL |
0 |
TRUE |
<Marker Id>, <Marker name>, <Marker size tag name> and <Marker size tag Id> are in table below:
| Marker |
<Marker name> |
<Marker Id> |
<Marker size tag name> |
<Marker size tag Id> |
| APP0 |
"APP0" |
0xFFE0 |
"APP0_DATASIZE" |
60224 |
| APP1 |
"APP1" |
0xFFE1 |
"APP1_DATASIZE" |
60225 |
| APP2 |
"APP2" |
0xFFE2 |
"APP2_DATASIZE" |
60226 |
| APP3 |
"APP3" |
0xFFE3 |
"APP3_DATASIZE" |
60227 |
| APP4 |
"APP4" |
0xFFE4 |
"APP4_DATASIZE" |
60228 |
| APP5 |
"APP5" |
0xFFE5 |
"APP5_DATASIZE" |
60229 |
| APP6 |
"APP6" |
0xFFE6 |
"APP6_DATASIZE" |
60230 |
| APP7 |
"APP7" |
0xFFE7 |
"APP7_DATASIZE" |
60231 |
| APP8 |
"APP8" |
0xFFE8 |
"APP8_DATASIZE" |
60232 |
| APP9 |
"APP9" |
0xFFE9 |
"APP9_DATASIZE" |
60233 |
| APP10 |
"APP10" |
0xFFEA |
"APP10_DATASIZE" |
60234 |
| APP11 |
"APP11" |
0xFFEB |
"APP11_DATASIZE" |
60235 |
| APP12 |
"APP12" |
0xFFEC |
"APP12_DATASIZE" |
60236 |
| APP13 |
"APP13" |
0xFFED |
"APP13_DATASIZE" |
60237 |
| APP14 |
"APP14" |
0xFFEE |
"APP14_DATASIZE" |
60238 |
| APP15 |
"APP15" |
0xFFEF |
"APP15_DATASIZE" |
60239 |
Callback Required for Writing JPEG Metadata Items
All JPEG metadata items can be written using LPAFT_IG_METAD_ITEM_ADD_CB callback only.
JPEG Metadata Item Name and ID Constants
Please see
enumIGJPGTagIDs for a complete list of JPEG Metadata Id constants.
