# JP2OpenJPEG --- JPEG2000 driver based on OpenJPEG library

(GDAL >= 1.8.0)

This driver is an implementation of a JPEG2000 reader/writer based on OpenJPEG library v2.

For GDAL 1.10 or later, use openjpeg 2.X.

For GDAL 1.9.x or before, use the v2 branch from its Subversion repository : http://openjpeg.googlecode.com/svn/branches/v2 (before r2230 when it was deleted).

The driver uses the VSI Virtual File API, so it can read JPEG2000 compressed NITF files.

Starting with GDAL 1.9.0, XMP metadata can be extracted from JPEG2000 files, and will be stored as XML raw content in the xml:XMP metadata domain.

Starting with GDAL 1.10, the driver supports writing georeferencing information as GeoJP2 and GMLJP2 boxes.

Starting with GDAL 2.0, the driver supports creating files with transparency, arbitrary band count, and adding/reading metadata. Update of georeferencing or metadata of existing file is also supported. Optional intellectual property metdata can be read/written in the xml:IPR box.

## Option Options

(GDAL >= 2.0 ) The following open option is available:

- 1BIT_ALPHA_PROMOTION=YES/NO: Whether a 1-bit alpha channel should be promoted to 8-bit. Defaults to YES.

## Creation Options

- CODEC=JP2/J2K : JP2 will add JP2 boxes around the codestream data. The value is determined automatically from the file extension. If it's neither JP2 nor J2K, J2K codec is used.

- GMLJP2=YES/NO: (Starting with GDAL 1.10) Indicates whether a GML box conforming to the OGC GML in JPEG2000 specification should be included in the file. Unless GMLJP2V2_DEF is used, the version of the GMLJP2 box will be version 1. Defaults to YES.

- GMLJP2V2_DEF=filename: (Starting with GDAL 2.0) Indicates whether a GML box conforming to the OGC GML in JPEG2000, version 2 specification should be included in the file. filename must point to a file with a JSon content that defines how the GMLJP2 v2 box should be built. See below section for the syntax of the JSon configuration file. It is also possible to directly pass the JSon content inlined as a string. If filename is just set to YES, a minimal instance will be built.

- GeoJP2=YES/NO: (Starting with GDAL 1.10) Indicates whether a UUID/GeoTIFF box conforming to the GeoJP2 (GeoTIFF in JPEG2000) specification should be included in the file. Defaults to YES.

- QUALITY=float_value,float_value,... : Percentage between 0 and 100. A value of 50 means the file will be half-size in comparison to uncompressed data, 33 means 1/3, etc.. Defaults to 25 (unless the dataset is made of a single band with color table, in which case the default quality is 100). Starting with GDAL 2.0, it is possible to specify several quality values (comma separated) to ask for several quality layers. Quality values should be increasing.

- REVERSIBLE=YES/NO : YES means use of reversible 5x3 integer-only filter, NO use of the irreversible DWT 9-7. Defaults to NO (unless the dataset is made of a single band with color table, in which case reversible filter is used).

- RESOLUTIONS=int_value : Number of resolution levels. Default value is selected such the smallest overview of a tile is no bigger than 128x128.

- BLOCKXSIZE=int_value : Tile width. Defaults to 1024.

- BLOCKYSIZE=int_value : Tile height. Defaults to 1024.

- PROGRESSION=LRCP/RLCP/RPCL/PCRL/CPRL : Progession order. Defaults to LRCP.

- SOP=YES/NO : YES means generate SOP (Start Of Packet) marker segments. Defaults to NO.

- EPH=YES/NO : YES means generate EPH (End of Packet Header) marker segments. Defaults to NO.

- YCBCR420=YES/NO : (GDAL >= 1.11) YES if RGB must be resampled to YCbCr 4:2:0. Defaults to NO.

- YCC=YES/NO : (GDAL >= 2.0) YES if RGB must be transformed to YCC color space ("MCT transform", i.e. internal transform, without visual degration). Defaults to YES.

- NBITS=int_value : (GDAL >= 2.0) Bits (precision) for sub-byte files (1-7), sub-uint16 (9-15), sub-uint32 (17-31).

- 1BIT_ALPHA=YES/NO: (GDAL >= 2.0) Whether to encode the alpha channel as a 1-bit channel (when there's an alpha channel). Defaults to NO, unless INSPIRE_TG=YES. Enabling this option might cause compatibility problems with some readers. At the time of writing, those based on the MrSID JPEG2000 SDK are unable to open such files. And regarding the ECW JPEG2000 SDK, decoding of 1-bit alpha channel with lossy/irreversible compression gives visual artifacts (OK with lossless encoding).

- ALPHA=YES/NO: (GDAL >= 2.0) Whether to force encoding last channel as alpha channel. Only useful if the color interpretation of that channel is not already Alpha. Defaults to NO.

- PROFILE=AUTO/UNRESTRICTED/PROFILE_1: (GDAL >= 2.0) Determine which codestream profile to use. UNRESTRICTED corresponds to the "Unrestricted JPEG 2000 Part 1 codestream" (RSIZ=0). PROFILE_1 corresponds to the "JPEG 2000 Part 1 Profile 1 codestream" (RSIZ=2), which add constraints on tile dimensions and number of resolutions. In AUTO mode, the driver will determine if the BLOCKXSIZE, BLOCKYSIZE, RESOLUTIONS, CODEBLOCK_WIDTH and CODEBLOCK_HEIGHT values are compatible with PROFILE_1 and advertize it in the relevant case. Note that the default values of those options are compatible with PROFILE_1. Otherwise UNRESTRICTED is advertized. Defaults to AUTO.

- INSPIRE_TG=YES/NO: (GDAL >= 2.0) Whether to use JPEG2000 features that comply with Inspire Orthoimagery Technical Guidelines. Defaults to NO. When set to YES, implies PROFILE=PROFILE_1, 1BIT_ALPHA=YES, GEOBOXES_AFTER_JP2C=YES. The CODEC, BLOCKXSIZE, BLOCKYSIZE, RESOLUTIONS, NBITS, PROFILE, CODEBLOCK_WIDTH and CODEBLOCK_HEIGHT options will be checked against the requirements and recommendations of the Technical Guidelines.

- JPX=YES/NO: (GDAL >= 2.0) Whether to advertize JPX features, and add a Reader requirement box, when a GMLJP2 box is written. Defaults to YES. This option should not be used unless compatibility problems with a reader occur.

- GEOBOXES_AFTER_JP2C=YES/NO: (GDAL >= 2.0) Whether to place GeoJP2/GMLJP2 boxes after the code-stream. Defaults to NO, unless INSPIRE_TG=YES. This option should not be used unless compatibility problems with a reader occur.

- PRECINCTS={prec_w,prec_h},{prec_w,prec_h},...: (GDAL >= 2.0) A list of {precincts width,precincts height} tuples to specify precincts size. Each value should be a multiple of 2. The maximum number of tuples used will be the number of resolutions. The first tuple corresponds to the higher resolution level, and the following ones to the lower resolution levels. If less tuples are specified, the last one is used by dividing its values by 2 for each extra lower resolution level. The default value used is {512,512},{256,512},{128,512},{64,512},{32,512},{16,512},{8,512},{4,512},{2,512}. An empty string may be used to disable precincts ( i.e. the default {32767,32767},{32767,32767}, ... will then be used).

- TILEPARTS=DISABLED/RESOLUTIONS/LAYERS/COMPONENTS: (GDAL >= 2.0) Whether to generate tile-parts and according to which criterion. Defaults to DISABLED.

- CODEBLOCK_WIDTH=int_value: (GDAL >= 2.0) Codeblock width: power of two value between 4 and 1024. Defaults to 64. Note that CODEBLOCK_WIDTH * CODEBLOCK_HEIGHT must not be greater than 4096. For PROFILE_1 compatibility, CODEBLOCK_WIDTH must not be greater than 64.

- CODEBLOCK_HEIGHT=int_value: (GDAL >= 2.0) Codeblock height: power of two value between 4 and 1024. Defaults to 64. Note that CODEBLOCK_WIDTH * CODEBLOCK_HEIGHT must not be greater than 4096. For PROFILE_1 compatibility, CODEBLOCK_HEIGHT must not be greater than 64.

- WRITE_METADATA=YES/NO: (GDAL >= 2.0) Whether metadata should be written, in a dedicated JP2 'xml ' box. Defaults to NO. The content of the 'xml ' box will be like:

      <GDALMultiDomainMetadata>
        <Metadata>
          <MDI key="foo">bar</MDI>
        </Metadata>
        <Metadata domain='aux_domain'>
          <MDI key="foo">bar</MDI>
        </Metadata>
        <Metadata domain='a_xml_domain' format='xml'>
          <arbitrary_xml_content>
          </arbitrary_xml_content>
        </Metadata>
      </GDALMultiDomainMetadata>

  If there are metadata domain whose name starts with "xml:BOX_", they will be written each as separate JP2 'xml ' box.

  If there is a metadata domain whose name is "xml:XMP", its content will be written as a JP2 'uuid' XMP box.

  If there is a metadata domain whose name is "xml:IPR", its content will be written as a JP2 'jp2i' box.

- MAIN_MD_DOMAIN_ONLY=YES/NO: (GDAL >= 2.0) (Only if WRITE_METADATA=YES) Whether only metadata from the main domain should be written. Defaults to NO.

- USE_SRC_CODESTREAM=YES/NO: (GDAL >= 2.0) (EXPERIMENTAL!) When source dataset is JPEG2000, whether to reuse the codestream of the source dataset unmodified. Defaults to NO. Note that enabling that feature might result in inconsistent content of the JP2 boxes w.r.t. to the content of the source codestream. Most other creation options will be ignored in that mode. Can be useful in some use cases when adding/correcting georeferencing, metadata, ... INSPIRE_TG and PROFILE options will be ignored, and the profile of the codestream will be overriden with the one specified/implied by the options (which may be inconsistent with the characteristics of the codestream).

### Lossless compression

Lossless compression can be achieved if ALL the following creation options are defined :

- QUALITY=100
- REVERSIBLE=YES
- YCBCR420=NO (which is the default)

### GMLJP2v2 definition file

A GMLJP2v2 box typically contains a GMLJP2RectifiedGridCoverage with the SRS information and geotransformation matrix. It is also possible to add metadata, vector features (GML feature collections), annotations (KML), styles (typically SLD, or other XML format) or any XML content as an extension. The value of the GMLJP2V2_DEF creation option should be a file that conforms with the below syntax (elements starting with "#" are documentation, and can be omitted):

    {
        "#doc" : "Unless otherwise specified, all elements are optional",

        "#root_instance_doc": "Describe content of the GMLJP2CoverageCollection",
        "root_instance": {
            "#gml_id_doc": "Specify GMLJP2CoverageCollection gml:id. Default is ID_GMLJP2_0",
            "gml_id": "some_gml_id",

            "#grid_coverage_file_doc": [
                "External XML file, whose root might be a GMLJP2GridCoverage, ",
                "GMLJP2RectifiedGridCoverage or a GMLJP2ReferenceableGridCoverage.",
                "If not specified, GDAL will auto-generate a GMLJP2RectifiedGridCoverage" ],
            "grid_coverage_file": "gmljp2gridcoverage.xml",

            "#crs_url_doc": [
                "true for http://www.opengis.net/def/crs/EPSG/0/XXXX CRS URL.",
                "If false, use CRS URN. Default value is true",
                "Only taken into account for a auto-generated GMLJP2RectifiedGridCoverage"],
            "crs_url": true,

            "#metadata_doc": [ "An array of metadata items. Can be either strings, with ",
                               "a filename or directly inline XML content, or either ",
                               "a more complete description." ],
            "metadata": [

                "dcmetadata.xml",

                {
                    "#file_doc": "Can use relative or absolute paths. Exclusive of content, gdal_metadata and generated_metadata.",
                    "file": "dcmetadata.xml",

                    "#gdal_metadata_doc": "Whether to serialize GDAL metadata as GDALMultiDomainMetadata",
                    "gdal_metadata": false,

                    "#dynamic_metadata_doc":
                        [ "The metadata file will be generated from a template and a source file.",
                          "The template is a valid GMLJP2 metadata XML tree with placeholders like",
                          "{{{XPATH(some_xpath_expression)}}}",
                          "that are evalated from the source XML file. Typical use case",
                          "is to generate a gmljp2:eopMetadata from the XML metadata",
                          "provided by the image provider in their own particular format." ],
                    "dynamic_metadata" :
                    {
                        "template": "my_template.xml",
                        "source": "my_source.xml"
                    },

                    "#content": "Exclusive of file. Inline XML metadata content",
                    "content": "<gmljp2:metadata>Some simple textual metadata</gmljp2:metadata>",

                    "#parent_node": ["Where to put the metadata.",
                                     "Under CoverageCollection (default) or GridCoverage" ],
                    "parent_node": "CoverageCollection"
                }
            ],

            "#annotations_doc": [ "An array of filenames, either directly KML files",
                                  "or other vector files recognized by GDAL that ",
                                  "will be translated on-the-fly as KML" ],
            "annotations": [
                "my.kml"
            ],

            "#gml_filelist_doc" :[
                "An array of GML files. Can be either GML filenames, ",
                "or a more complete description" ],
            "gml_filelist": [

                "my.gml",

                {
                    "#file_doc": "Can use relative or absolute paths. Exclusive of remote_resource",
                    "file": "converted/test_0.gml",

                    "#remote_resource_doc": "URL of a feature collection that must be referenced through a xlink:href",
                    "remote_resource": "http://svn.osgeo.org/gdal/trunk/autotest/ogr/data/expected_gml_gml32.gml",

                    "#namespace_doc": ["The namespace in schemaLocation for which to substitute",
                                      "its original schemaLocation with the one provided below.",
                                      "Ignored for a remote_resource"],
                    "namespace": "http://example.com",

                    "#schema_location_doc": ["Value of the substitued schemaLocation. ",
                                             "Typically a schema box label (link)",
                                             "Ignored for a remote_resource"],
                    "schema_location": "gmljp2://xml/schema_0.xsd",

                    "#inline_doc": [
                        "Whether to inline the content, or put it in a separate xml box. Default is true",
                        "Ignored for a remote_resource." ],
                    "inline": true,

                    "#parent_node": ["Where to put the FeatureCollection.",
                                     "Under CoverageCollection (default) or GridCoverage" ],
                    "parent_node": "CoverageCollection"
                }
            ],

            "#styles_doc: [ "An array of styles. For example SLD files" ],
            "styles" : [
                {
                    "#file_doc": "Can use relative or absolute paths.",
                    "file": "my.sld",

                    "#parent_node": ["Where to put the FeatureCollection.",
                                     "Under CoverageCollection (default) or GridCoverage" ],
                    "parent_node": "CoverageCollection"
                }
            ],

            "#extensions_doc: [ "An array of extensions." ],
            "extensions" : [
                {
                    "#file_doc": "Can use relative or absolute paths.",
                    "file": "my.xml",

                    "#parent_node": ["Where to put the FeatureCollection.",
                                     "Under CoverageCollection (default) or GridCoverage" ],
                    "parent_node": "CoverageCollection"
                }
            ]
        },

        "#boxes_doc": "An array to describe the content of XML asoc boxes",
        "boxes": [
            {
                "#file_doc": "can use relative or absolute paths. Required",
                "file": "converted/test_0.xsd",

                "#label_doc": ["the label of the XML box. If not specified, will be the ",
                              "filename without the directory part." ],
                "label": "schema_0.xsd"
            }
        ]
    }

Metadata can be dynamically generated from a template file (in that context, with a XML structure) and a XML source file. The template file is processed by searching for patterns like {{{XPATH(xpath_expr)}}} and replacing them by their evaluation against the content of the source file. xpath_expr must be a XPath 1.0 compatible expression, with the addition of the following functions :

- if(cond_expr,expr_if_true,expr_if_false): if cond_expr evalutes to true, returns expr_if_true. Otherwise returns expr_if_false
- uuid(): evaluates to a random UUID

A template file to process XML metadata of Pleiades imagery can be found here, and a template file to process XML metadata of GeoEye/WorldView imagery can be found here.

## Vector information

Starting with GDAL 2.0, a JPEG2000 file containing a GMLJP2 v2 box with GML feature collections and/or KML annotations embedded can be opened as a vector file with the OGR API. For example:

    ogrinfo -ro my.jp2

    INFO: Open of my.jp2'
          using driver `JP2OpenJPEG' successful.
    1: FC_GridCoverage_1_rivers (LineString)
    2: FC_GridCoverage_1_borders (LineString)
    3: Annotation_1_poly

Feature collections can be linked from the GMLJP2 v2 box to a remote location. By default, the link is not followed. It will be followed if the open option OPEN_REMOTE_GML is set to YES.

## See Also:

- Implemented as `gdal/frmts/openjpeg/openjpegdataset.cpp`.

- Official JPEG-2000 page

- The OpenJPEG library home page

- Inspire Data Specification on Orthoimagery - Technical Guidelines

Other JPEG2000 GDAL drivers :

- JPEG2000: based on Jasper library (open source)

- JP2ECW: based on Erdas ECW library (proprietary)

- JP2MRSID: based on LizardTech MrSID library (proprietary)

- JP2KAK: based on Kakadu library (proprietary)