The .mvnx file format
The MVNX (Moven Open XML format) files contains 3D position, 3D orientation, (and optionally; 3D acceleration, 3D velocity, 3D angular rate, 3D angular acceleration) of each segment (not the sensors) in XML format (ASCII). The following documentation is extracted partially from the XSens original documentation and by review of example files. There are still open point with unknow undocumented behavoir.
The MVNX file starts with a version number:
The <mvnxInfo> section contains information about the number of frames, the frame rate, recording date, original MVN file, and the contents of velocity, acceleration, angular velocity or angular acceleration data.
<mvnxInfo frameCount="1000" frameRate="100" recDate="0" originalFilename="c:\data\session‐001.mvn" velData="1" accData="0" angVelData="1" angAccData="0"/>
|frameCount||count of frames|
|frameRate||frames per second|
|recDate||Unknow format, e.g. 1239100243 recorded 2009|
|originalFilename||absolute path to the original „.mvn“ file|
|velData||0||set to „1“ if position velocity data is available|
|accData||0||set to „1“ if position acceleration data is available|
|angVelData||0||set to „1“ if angular velocity data is available|
|angAccData||0||set to „1“ if angular acceleration data is available|
The section <markers> contains the description of markers with frame number and marker name if present. In comparison with nomenclature of Vicon Workstation, markers are events. But there are no event types. It seems to be allowed to define more than one marker with the same name (event type) in a trial. Instead of the common c3d-format the position of the marker is defined by an integer instead of a double defining a real time point with optional definition of a range.
<markers> <marker frame="123" name="RHS"/> <marker frame="340" name="RTO"/> </markers>
For compatiblity the following table shows the Vicon workstation event type names and its meaning, which must be used for correct gait cycle detection also for the XSens system to be compatible with the Nimue-Platform applications.
|Marker (event) name||Description|
|RHS||right foot strike|
|LHS||left foot strike|
|RTO||right foot off|
|LTO||left foot off|
|LG||special meaning in the gaitlab heidelberg: 1. between LHS and LTO to indicate that the kinetics is usable, 2. if there are more then one of this events between LHS and LTO first and last LG event defines start and end of a foot flat phase of the left side|
|RG||special meaning in the gaitlab heidelberg: 1. between RHS and RTO to indicate that the kinetics is usable, 2. if there are more then one of this events between RHS and RTO first and last RG event defines start and end of a foot flat phase of the right side|
|GG||general event of no specific side|
The section <comment> contains the text which has been entered when creating a new recording session.
The <meshScale> data is used for scaling of the visualization of the character in Moven Studio.
The section <segments> defines all positions of connecting joints and anatomical landmarks with respect to origin of that segment (in body frame B).
<segment id="16" label="RightUpperLeg"> <point label="jRightHip" pos_s="0.000000 0.000000 0.000000"/> <point label="jRightKnee" pos_s="0.000000 0.000000 ‐0.417462"/> ... </segment>
unvollständig, da gibts noch einiges an Doku in der ursprünglichen html-doku