Knowledge Base

Synchronize Data Sets

Aim

To change the Start Time of a data set (Event Log, Video, Audio, External Data) relative to others.

• Example 1: You started video recording with one camera 30 seconds earlier than with the other. Before observing, you want to synchronize the video files.
• Example 2: After the observation, you imported associated physiological data and want to synchronize it with the events.

Prerequisite

An event must be recognizable in all streams to synchronize. For example, you press a key assigned to a behavior in the Coding Scheme and record that on video. The key press will appear in the Event Log and be visible in the video. When recording external data without automatic synchronization, the event should also be recognizable in the external data.

Procedure

1. Open an existing observation and make sure that the video, audio, and external data linked to the observation are visible on your screen. If a data set is not shown, click View Settings on the far-right side of the toolbar and select that option.
2. Synchronize data sets in one of two ways: numerically by typing an offset value, or manually by moving the slider of the video file or dragging the visual presentation of the data set.

Numerical Offset

1. Click the Offset button on the Component toolbar, then choose Numerical Offset. The File Synchronization window appears, listing the open Event Log, video and audio files, and linked external data.
2. Locate the data set (event, video, audio, or external data) whose start time you want to change relative to others, and click its Offset cell.
3. Enter the offset value. Example: If your Event Log starts 20 seconds after the video file, locate the row of the video file and enter -20 in the seconds group of the Offset column.
4. Click Apply.

Manual Offset

1. Click the Offset button on the Component toolbar, then choose Manual Offset. The Synchronize window appears explaining the next steps. Click Start Synchronization.
2. Click the window with the data you want to synchronize. A red border appears around the window. You can now alter the time in this window while the time in other windows remains fixed.
3. Position the video, audio, or external data to the matching event in the Event Log:
   • Video or audio: Use the Playback Control buttons to play the media file to the new position.
   • External data: Click the window and move the data stream with the cursor to the new position.
4. Click the Offset button again. The red border disappears and the files are synchronized as specified.

Notes

• If you use MediaRecorder 4 or higher to record video, the video files are automatically synchronized with your observation.
• You can use the File Synchronization window to check that the time difference between video, audio, Event Log, and other data streams is correct. You can change this difference at any time.

Change the Observation's Start Time and Duration

By default, the Start Time and Stop Time of an observation are the earliest Start Time and the latest Stop Time of any data set in that observation. These times are found in the Independent Variable List (Setup > Independent Variables). If you want to exclude a section at the beginning of the observation, or if you stopped the observation too early, you can change the Start Time and Duration. The Stop Time is determined automatically from the Start Time and Duration.

Changing the Start Time and/or Duration does not move Event Logs, Video, Audio, or External Data files. For example, reducing the Start Time moves the Start point earlier but does not shift the associated files, resulting in a larger gap between the Start Time and the beginning of the files.

Procedure

1. Choose Setup > Independent Variables.
2. Choose View Settings > Show Independent Variables and select Start Time, Stop Time, and Duration.
3. Edit the Start Time or Duration cell.

Notes

• Changing the observation Start Time or Duration does not affect synchronization between individual files. To change synchronization between files, see Synchronize Data Sets.
• The observation Stop Time is updated automatically based on changes to the Start Time and Duration, and cannot be edited directly.
• Events recorded before the Start Time or after the Stop Time of the observation are shown in gray in the Event Log.