dcmcrle(1) OFFIS DCMTK dcmcrle(1) # [NAME](#NAME) dcmcrle - Encode DICOM file to RLE transfer syntax # [SYNOPSIS](#SYNOPSIS) ``` dcmcrle [options] dcmfile-in dcmfile-out ``` # [DESCRIPTION](#DESCRIPTION) The **dcmcrle** utility reads an uncompressed DICOM image (*dcmfile-in*), performs RLE compression (i.e. conversion to an encapsulated DICOM transfer syntax) and writes the converted image to an output file (*dcmfile-out*). # [PARAMETERS](#PARAMETERS) ``` dcmfile-in DICOM input filename to be converted ('-' for stdin) dcmfile-out DICOM output filename ('-' for stdout) ``` # [OPTIONS](#OPTIONS) ## [general options](#general_options) ``` -h --help print this help text and exit --version print version information and exit --arguments print expanded command line arguments -q --quiet quiet mode, print no warnings and errors -v --verbose verbose mode, print processing details -d --debug debug mode, print debug information -ll --log-level [l]evel: string constant (fatal, error, warn, info, debug, trace) use level l for the logger -lc --log-config [f]ilename: string use config file f for the logger ``` ## [input options](#input_options) ``` input file format: +f --read-file read file format or data set (default) +fo --read-file-only read file format only -f --read-dataset read data set without file meta information input transfer syntax: -t= --read-xfer-auto use TS recognition (default) -td --read-xfer-detect ignore TS specified in the file meta header -te --read-xfer-little read with explicit VR little endian TS -tb --read-xfer-big read with explicit VR big endian TS -ti --read-xfer-implicit read with implicit VR little endian TS ``` ## [encapsulated pixel data encoding options](#encapsulated_pixel_data_encoding_options) ``` pixel data fragmentation: +ff --fragment-per-frame encode each frame as one fragment (default) +fs --fragment-size [s]ize: integer limit fragment size to s kbytes (non-standard) basic offset table encoding: +ot --offset-table-create create offset table (default) -ot --offset-table-empty leave offset table empty icon image encoding: +ic --icon-compressed compress icon images (default) +iu --icon-uncompressed keep icon images uncompressed SOP Class UID: +cd --class-default keep SOP Class UID (default) +cs --class-sc convert to Secondary Capture Image (implies --uid-always) SOP Instance UID: +un --uid-never never assign new UID (default) +ua --uid-always always assign new UID ``` ## [output options](#output_options) ``` post-1993 value representations: +u --enable-new-vr enable support for new VRs (UN/UT) (default) -u --disable-new-vr disable support for new VRs, convert to OB group length encoding: +g= --group-length-recalc recalculate group lengths if present (default) +g --group-length-create always write with group length elements -g --group-length-remove always write without group length elements length encoding in sequences and items: +e --length-explicit write with explicit lengths (default) -e --length-undefined write with undefined lengths data set trailing padding: -p= --padding-retain do not change padding (default) -p --padding-off no padding +p --padding-create [f]ile-pad [i]tem-pad: integer align file on multiple of f bytes and items on multiple of i bytes ``` # [NOTES](#NOTES) The **dcmcrle** utility compresses DICOM images of all SOP classes. It processes all Pixel Data (7fe0,0010) elements in the dataset, i.e. compression is also performed on an icon image. Please note that the DICOM standard does not allow for storing the pixel data with multiple fragments per frame (when RLE compression is used). So limiting the fragment size with option *--fragment-size* (or *+fs*) may result in a non-standard compliant DICOM image. # [TRANSFER SYNTAXES](#TRANSFER_SYNTAXES) **dcmcrle** supports the following transfer syntaxes for input (*dcmfile-in*): ``` LittleEndianImplicitTransferSyntax 1.2.840.10008.1.2 LittleEndianExplicitTransferSyntax 1.2.840.10008.1.2.1 DeflatedExplicitVRLittleEndianTransferSyntax 1.2.840.10008.1.2.1.99 (*) BigEndianExplicitTransferSyntax 1.2.840.10008.1.2.2 ``` (\*) if compiled with zlib support enabled **dcmcrle** supports the following transfer syntaxes for output (*dcmfile-out*): ``` RLELosslessTransferSyntax 1.2.840.10008.1.2.5 ``` # [LOGGING](#LOGGING) The level of logging output of the various command line tools and underlying libraries can be specified by the user. By default, only errors and warnings are written to the standard error stream. Using option *--verbose* also informational messages like processing details are reported. Option *--debug* can be used to get more details on the internal activity, e.g. for debugging purposes. Other logging levels can be selected using option *--log-level*. In *--quiet* mode only fatal errors are reported. In such very severe error events, the application will usually terminate. For more details on the different logging levels, see documentation of module 'oflog'. In case the logging output should be written to file (optionally with logfile rotation), to syslog (Unix) or the event log (Windows) option *--log-config* can be used. This configuration file also allows for directing only certain messages to a particular output stream and for filtering certain messages based on the module or application where they are generated. An example configuration file is provided in *<etcdir>/logger.cfg*. # [COMMAND LINE](#COMMAND_LINE) All command line tools use the following notation for parameters: square brackets enclose optional values (0-1), three trailing dots indicate that multiple values are allowed (1-n), a combination of both means 0 to n values. Command line options are distinguished from parameters by a leading '+' or '-' sign, respectively. Usually, order and position of command line options are arbitrary (i.e. they can appear anywhere). However, if options are mutually exclusive the rightmost appearance is used. This behavior conforms to the standard evaluation rules of common Unix shells. In addition, one or more command files can be specified using an '@' sign as a prefix to the filename (e.g. *@command.txt*). Such a command argument is replaced by the content of the corresponding text file (multiple whitespaces are treated as a single separator unless they appear between two quotation marks) prior to any further evaluation. Please note that a command file cannot contain another command file. This simple but effective approach allows one to summarize common combinations of options/parameters and avoids longish and confusing command lines (an example is provided in file *<datadir>/dumppat.txt*). # [ENVIRONMENT](#ENVIRONMENT) The **dcmcrle** utility will attempt to load DICOM data dictionaries specified in the *DCMDICTPATH* environment variable. By default, i.e. if the *DCMDICTPATH* environment variable is not set, the file *<datadir>/dicom.dic* will be loaded unless the dictionary is built into the application (default for Windows). The default behavior should be preferred and the *DCMDICTPATH* environment variable only used when alternative data dictionaries are required. The *DCMDICTPATH* environment variable has the same format as the Unix shell *PATH* variable in that a colon (':') separates entries. On Windows systems, a semicolon (';') is used as a separator. The data dictionary code will attempt to load each file specified in the *DCMDICTPATH* environment variable. It is an error if no data dictionary can be loaded. # [SEE ALSO](#SEE_ALSO) [**dcmdrle**(1)](/man/os/dcmtk/dcmdrle.1) # [COPYRIGHT](#COPYRIGHT) Copyright (C) 2002-2026 by OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany. Thu Oct 15 2026 Version 3.7.1 --- Document: dcmcrle(1) from dcmtk 3.7.1-r0 (Chainguard OS) Source: https://github.com/DCMTK/dcmtk