mdfminer

The project's goal is to parse a "measurement data format" files (.mdf,.dat) and provide the contents in a useful manner.

Mdf is widely used in the automotive industry and ASAM related environments. The format specification for Version 3.3 is available for download at https://vector.com/downloads/mdf_specification.pdf . Currently (Dec 2016) Format Version 4.X is the latest but the format specification is not available to the public.

The mdf file format consists of a tree like structure to describe the contents referring to the file offset of the next block.

Tree Structure of MDF File

ID Block
  HD Block
    TX Block(File comment)(optional)
    PR Block(Program Specific Data)(optional)
    DG Block(Data Group)
    Data Record(binary)
      Trigger Block(TimingInformation)(optional)
      CG Block(s)(Channel Group(s))(optional)
        CN Block(s)(Channel(s))(optional)
        TX Block(Channel Comment)(optional)
        TX Block(Unique Identifier)
        CC Block(Channel Conversion Rule)(optional)
        CD Block(Dependencies)(optional)
        CE Block(Extentions)(optional)

How MDF works

The measurement data is in the Data Record of the DG Block presenting an array of records. The record prototype is defined by the Channel Group of the DG Block. The Channel Group consists of channels (single measurements) and basically cuts the record into chuncks defined by bit offset and bit length. The channels itself have a Conversion Rule on how to compute a real value out of the raw data and also provide information what physical value results.

How mdfminer works

When loading a mdf file, the tree is read but the binary data is not touched yet. Parsing the tree is usually very fast since it only depends on the number of channels regardless on how long the measurement really is.

Getting measurements from the mdf object with "get_records_with_timestamp()" is done by a generator function, so the memory footprint and execution time is low until the next set of values is yield. A set of values is presented as a common python dictionary.

Usage

#import the module
import mdfminer

#create an mdf object from a recorder file
m = mdfminer.mdf(fname=r"c:\Recorder1-001.mdf")

#retrieve file version
print(m.version)
3.1

#you can dump the data into an xlsx file,
#although it is not recommended practice for data analysis
mdfminer.to_xlsx_file(m,r"c:\recorder.xlsx",useabsolutetime=True)

#recommended practice for data analysis would be feeding the generator data to your own program 
for rec in m.get_records_with_timestamp(useabsolutetime=True):
    analyze_data(rec)