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File Format Limitations

MDF Files

The following restrictions apply to MDF file operations.

  • mdfVisualize supports only integer, floating point, and string data types in MDF file channels.

  • The following MDF file functions do not support the full range of international characters that are supported by the other MDF functions:

  • mdfCreate does not support adding custom file metadata fields.

  • mdfInfo does not return custom file metadata fields.

  • mdfRead is restricted in the following ways:

    • mdfRead does not support array channels with more than 3 dimensions.

    • Reading from a nested composition of channels is not supported. You can read from simple structure channels or array channels, but not from a structure or array of composed signals.

    • mdfRead ignores invalidation bits, so there is no indication of invalid samples and no errors or warnings. mdfRead simply reads in the data value as stored at the record position in the MDF file.

    • mdfRead does not support reading from channels with partial conversion rules.

  • mdfWrite is restricted in the following ways:

    • Boolean is not a supported data type in the MDF standard, so mdfWrite does not support the logical data type. To work around this limitation, convert the logical variable to an int8 or uint8 data type before writing to the MDF file.

    • The mdfWrite function does not support writing array channels or structure channels.

    • When overwriting an existing channel, use a timetable that was created by the mdfRead function with the option IncludeMetadata=true. Do not remove any timetable custom properties returned by the mdfRead function.

    • When overwriting an existing channel, the ChannelReadOption property in the timetable custom properties is used internally to keep track of the kind of conversion rule applied during the read. Do not modify this custom property in the timetable.

    • When writing a new channel to an MDF file, the mdfWrite function does not support writing data with conversion rules. Only raw values can be written to new channels.

  • mdfFinalize might be unable to write to a new or existing MDF file at a remote URL location from MATLAB® Online™ or Linux®. To work around this limitation, first write the finalized file to MATLAB Drive™ (from MATLAB Online) or to a local folder (from Linux), and then move the finalized MDF file to the necessary location.

CDFX Files

When using CDFX files, the following limitations apply:

  • SW-AXIS-CONT elements with the category COM_AXIS, CURVE_AXIS, or RES_AXIS must use the SW-INSTANCE-REF element, and the axis must be defined in a separate instance.

  • Instances with the category VAL_BLK, CUBOID, CUBE_4, or CUBE_5 that represent multidimensional arrays must use the VG element to group the physical values.

BLF Files

Although Vector BLF files support many networks, Vehicle Network Toolbox™ support of BLF files is limited to only CAN and CAN FD on Windows® and Linux operating systems.

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