mdfChannelInfo

Get channel metadata from MDF file

Since R2023a

Syntax

infoTable = mdfChannelInfo(mdfFileName)

infoTable = mdfChannelInfo(___,Name=Value)

Description

infoTable = mdfChannelInfo(mdfFileName) returns a table of information about all channels in the specified MDF file.

infoTable = mdfChannelInfo(___,Name=Value) allows specified name-value arguments to filter on specific channels and channel groups, and determine the amount of metadata returned.

Examples

Get Channel Information from MDF File

Access the channel information in an MDF file.

Get information on all channels.

ci = mdfChannelInfo("VehicleData.mf4")

ci =
  12×13 table

          Name           GroupNumber    GroupNumSamples    GroupAcquisitionName                                   GroupComment                                    GroupSourceName    GroupSourcePath    DisplayName       Unit          Comment     ExtendedNamePrefix    SourceName     SourcePath 
    _________________    ___________    _______________    ____________________    ___________________________________________________________________________    _______________    _______________    ___________    ___________    ___________   __________________    ___________    ___________

    "AirFlow"                 2              92033             <undefined>         Simulation of engine gas dynamics.                                               <undefined>        <undefined>          ""         g/s            <undefined>      <undefined>        <undefined>    <undefined>
    "Brake"                   1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         ft*lbf         <undefined>      <undefined>        <undefined>    <undefined>
    "EngineRPM"               1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         rpm            <undefined>      <undefined>        <undefined>    <undefined>
    "FuelRate"                2              92033             <undefined>         Simulation of engine gas dynamics.                                               <undefined>        <undefined>          ""         g/s            <undefined>      <undefined>        <undefined>    <undefined>
    "Gear"                    1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         <undefined>    <undefined>      <undefined>        <undefined>    <undefined>
    "ImpellerTorque"          1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         ft*lbf         <undefined>      <undefined>        <undefined>    <undefined>
    "OutputTorque"            1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         ft*lbf         <undefined>      <undefined>        <undefined>    <undefined>
    "Throttle"                1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         %              <undefined>      <undefined>        <undefined>    <undefined>
    "TransmissionRPM"         1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         rpm            <undefined>      <undefined>        <undefined>    <undefined>
    "VehicleSpeed"            1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         mph            <undefined>      <undefined>        <undefined>    <undefined>
    "time"                    1                751             <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         s              <undefined>      <undefined>        <undefined>    <undefined>
    "time"                    2              92033             <undefined>         Simulation of engine gas dynamics.                                               <undefined>        <undefined>          ""         s              <undefined>      <undefined>        <undefined>    <undefined>

View information for specific channels.

ci = mdfChannelInfo("VehicleData.mf4",Channel="*Torque")

ci =
  2×13 table

          Name          GroupNumber    GroupNumSamples    GroupAcquisitionName                                   GroupComment                                    GroupSourceName    GroupSourcePath    DisplayName     Unit       Comment      ExtendedNamePrefix    SourceName     SourcePath 
    ________________    ___________    _______________    ____________________    ___________________________________________________________________________    _______________    _______________    ___________    ______    ___________    __________________    ___________    ___________

    "ImpellerTorque"         1               751              <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         ft*lbf    <undefined>       <undefined>        <undefined>    <undefined>
    "OutputTorque"           1               751              <undefined>         Simulation of an automatic transmission controller during passing maneuver.      <undefined>        <undefined>          ""         ft*lbf    <undefined>       <undefined>        <undefined>    <undefined>

View channel information in one channel group.

ci = mdfChannelInfo("VehicleData.mf4",GroupNumber=2)

ci =
  3×13 table

       Name       GroupNumber    GroupNumSamples    GroupAcquisitionName               GroupComment               GroupSourceName    GroupSourcePath    DisplayName    Unit      Comment      ExtendedNamePrefix    SourceName     SourcePath 
    __________    ___________    _______________    ____________________    __________________________________    _______________    _______________    ___________    ____    ___________    __________________    ___________    ___________

    "AirFlow"          2              92033             <undefined>         Simulation of engine gas dynamics.      <undefined>        <undefined>          ""         g/s     <undefined>       <undefined>        <undefined>    <undefined>
    "FuelRate"         2              92033             <undefined>         Simulation of engine gas dynamics.      <undefined>        <undefined>          ""         g/s     <undefined>       <undefined>        <undefined>    <undefined>
    "time"             2              92033             <undefined>         Simulation of engine gas dynamics.      <undefined>        <undefined>          ""         s       <undefined>       <undefined>        <undefined>    <undefined>

Request additional metadata on multiple channel matches. View only the first and additional table columns.

ci = mdfChannelInfo("VehicleData.mf4",Channel=["*Torque","*Rate"],AdditionalMetadata=true);
ci(:,[1,14:25])

ans =
  3×13 table

          Name             Type        SyncType        DataType        NumBits    ComponentType    CompositionType    ConversionType    SourceComment    SourceType     SourceBusType    SourceBusChannelNumber    SourceSimulated
    ________________    ___________    ________    ________________    _______    _____________    _______________    ______________    _____________    ___________    _____________    ______________________    _______________

    "FuelRate"          FixedLength      None      RealLittleEndian      64           None              None           Unspecified           ""          Unspecified     Unspecified               0                    false     
    "ImpellerTorque"    FixedLength      None      RealLittleEndian      64           None              None           Unspecified           ""          Unspecified     Unspecified               0                    false     
    "OutputTorque"      FixedLength      None      RealLittleEndian      64           None              None           Unspecified           ""          Unspecified     Unspecified               0                    false     

Input Arguments

mdfFileName — MDF file name

string | char vector

MDF file name, specified as a string or character vector, including the necessary full or relative path. You can use a URL to specify a file on a remote server.

Depending on the location you are accessing, mdfFileName can take one of these forms.

Location	Form
Current folder or MATLAB® path	To access a file in the current folder or MATLAB path, specify the name of the file in filename, including the file extension. Example: "myMdfFile.mf4"
Other folders	To access a file in a folder other than the current folder, specify the full or relative path name in filename. Example: "C:\myFolder\myMdfFile.mf4" Example: "\dataDir\myMdfFile.mf4"
Remote locations	To access a file in a remote location, filename must contain the full path of the file specified as a uniform resource locator (URL) of the form: scheme://path_to_file/myMdfFile.mf4 Based on the remote location, scheme can be one of the values in this table. Remote Location scheme Amazon S3™ s3 Windows Azure® Blob Storage wasb, wasbs HDFS™ hdfs For more information, see Work with Remote Data. Example: "s3://bucketname/path_to_file/myMdfFile.mf4"

Data Types: string | char

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: GroupNumber=2

GroupNumber — Channel group number

numeric

Channel group number, specified as a numeric scalar for one group, or numeric vector for multiple groups. The function returns channels found only in these specified channel groups. If unspecified, metadata for all channel groups are returned.

Example: GroupNumber=[1,2]

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Channel — Channel names

string | char | cell

Channel names, specified as a string or array of strings, or as a character vector or cell array of character vectors. Use an array to match on any of multiple channel names. Wildcards allow partial matching. If unspecified, metadata for all channels are returned.

Example: Channel=["*Rate","*Speed"]

Data Types: string | char | cell

AdditionalMetadata — Return additional metadata

false (default) | true

Return additional channel metadata, specified as true or false.

Example: AdditionalMetadata=true

Data Types: logical

Output Arguments

infoTable — Channel information

table

Channel information returned in a table of channels.

Version History

Introduced in R2023a

R2023a: Support for Remote File URLs

You can directly access MDF file data stored at remote locations, including Amazon S3, Azure^® Blob Storage, and HDFS.