Recover a streamed recording from logged data

Occasionally, it may be necessary or desirable to recover a streamed recording from the data stored on the Opals themselves. For example, a streamed recording may be accidentally erased. Alternately, you may have encountered an issue with the streaming of the data, and believe that the data may be correctly stored on the Opals. The steps below describe how you can retrieve the recording from the logged data and assign it to a trial in Mobility Lab.

Determine the time span of the streamed data file

  • Open the streamed recording in HDF View
  • Navigate to the Time entry for one of the Opals and double click on it to display the array of timestamps for the recording
  • Write down or cut and paste the first and last timestamp in the recording

Import and Conversion of Logged Data

  • Dock your monitors.
  • Click on View->"Motion Studio View" in the menu bar
  • Click on the "Import" button
  • When you open the import manager, the data from all currently docked Opals are moved to an import directory within the installation folder on your PC. These raw data files are displayed in the table at the top of the import directory. At the bottom of the dialog is a status indicator to help guide you through the conversion process.
  • Selecting data for import:
    • In the table at the top of the Import and Conversion Manager, you select data for conversion by checking the checkboxes of the files you wish to convert.

    • When you select a file in the table by clicking anywhere on the row, any other files that have overlapping recording times will be highlighted. This functionality aids in finding and merging of data that was recorded on multiple monitors synchronously. You should confirm that recordings from each of your recordings sites (e.g., left arm) are highlighted.

    • You can click on the "Select Highlighted" button to select these overlapping recordings.
  • Extracting your desired segment:
    • Recordings logged on different Opals will, in general, not perfectly overlap with each other in the time domain. This is because logging begins as soon as the Opal is undocked and stops as soon as it is docked again. Unless you undock and dock your Opals at exactly the same time, each Opal will log data from slightly different time spans. Using the timestamps generated on each Opal, however, it is possible to extract synchronized data from a group of Opals whose recordings overlap. The Time Range tool will help you extract synchronized data from your logged recordings.

    • Button Events: Note that button events are not yet supported for our v2 hardware (as of February, 2017). This is planned to be implemented in the future.
    • When you select a group of overlapping recordings, the Time Range tool will display the earliest and latest common time within the group. This is the time span for which data is available from all of the selected devices. By default, this is the data that will be converted.

    • If the selected files do not overlap temporally, you will not be able to convert the data.

    • To crop this recording to correspond to the start times of your trial, click on the "Custom Start Time" checkbox in the "Start Time" panel.

    • You can now either specify the start crop time by choosing a time (click on the "Time" button) or a button event (click on the "Marker" button). Note that timestamps copied from an HDF recording are at a finer time resolution (microseconds instead of milliseconds), so you will have to leave off the last 3 digits.
    • Do the same for the end time.
    • Click the "Convert" button. Your recording will be saved to the currently selected folder in the Data Explorer panel. You can right click on the file and look at the info to get the exact location on your hard disk.

Assigning a recording to a Trial

  • Click on View->"Mobility View" to go back to the Mobility Lab interface
  • Select the subject that you wish to assign the trial to
  • Click on the cog icon in the top right of the user interface and select the "Create trial from recording" option
  • Select the HDF recording that you just exported through the Import and Conversion Manager
  • Choose the test type and condition
  • Press the "Create" button
  • The timestamps in the file are automatically used to determine the trial date and the trial will be analyzed

 

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