Synchronizing Video with Odin

Configure Video with Trial data

This section explains the process for adding manually-synchronized contextual Video information to an trial. This is used typically when a separate video system (one or more cameras) has been used to capture video data alongside a trial, but without any synchronization at the time of acquisition. The manual synchronisation allows the system to playback the configured video channels alongside its own 3D motion data.

Each trial can link with up to four synchronized video channels. Each channel can be independently synchronized to the trial data, using the following process.

System Requirements:

1. ODIN or higher.

2. VLC Media Player 2.2.1 (Win 32) or higher.

3. Dual-Screen computer (Optional).

Setting up to displaying video is a two-stage process:

  • Synchronise the video or videos (up to 4) to the 3D trial
  • Create a Video view in which to display the video

It does not matter which order you do these two stages, but for the purposes of these instructions, we will do the synchronisation first.

Synchronise a Video to 3D data

a) Open the required protocol and trial, and select the trial to which you want to configure a video. Ensure that the main window is displaying a layout that contains the appropriate 3D views / Graphs. This will help you synchronize your video-data.

b) From the Utilities menu, select “Configure Video Channels”, or press CTRL+V from the main screen,

c) This will open the “Trial Video Properties” dialog. This lists a set of four pre-defined “empty” video channels. Each channel is uniquely identified with a channel ID. They are “Video 1”, “Video 2”, “Video 3”, “Video 4”.

d) Selecting a particular channel should activate the “Edit” button. This button is activated every time a video channel is selected. Notice that the “Clear button”(X) is greyed-out. This is because these channels are empty at the moment and there is nothing to clear.

When working on an empty channel, click on the Edit button to open the “File chooser” dialogue.

e) Browse the file system and select the required Video file. Click on Open,

f) If the selected file is a valid video file or if the channel already contains some video file association, you should see the “Video channel editor” dialogue. This is automatically set to display on the second monitor if one is available. This allows you to view the main window (3D views / Graphs) while editing the video channel. NOTE: You will see an Error message indicating the lack of VLC Player if it has not already been installed. The channel editor dialogue contains four sections as labelled in the picture below.

g) If your video data was hardware synchronized with the Codamotion system, you can simply select the “Lock” Button and click on the OK button on this dialogue box. This will associate the video-file with the currently active trial, without any synch parameters (more about this later). This indicates that time zero is the same as Video time zero.

h) The video control panel is used to preview and control playback of the selected video channel. Use this panel to perform the following tasks:

  • Load a different video file. This simply replaces the video path associated with that channel.
  • Step back/forward individual frames of the video using the “Prev Frame” and “Next Frame” buttons.
  • Play/Pause/Stop the video.
  • Use the “-“and “+” buttons to increase or decrease the preview speed. The panel in between these two buttons indicates the current preview speed (1X, 2X, 4X etc)
  • Use the Time slider bar to preview a particular moment in time in the Video. The text box on the left-hand side of the Time slider indicates the current video time, and the one on the right-hand side indicates the total video time.
  • Use the Frame slider bar to preview a particular frame in the video. The frame panel also contains the “Centre” button. It changes the minimum and maximum of the Frame slider bar such that the current video frame is always in the centre of the slider bar. You can use the Range +/- combo box to adjust the range of the slider bar. (10, 20, 50…frames). The text box on the left-hand side of the Frame slider bar indicates the current video frame being displayed, while the text box on the right-hand side displays the total number of frames.
  • Adjust the video preview volume using the Volume slider.

i) The control panel can be used to play through the selected trial data, just like the transport bar in the Main panel (which is disabled when the video control dialogue is open). Use the time slider to control the current cursor position of the currently active trial.

j) The Synch panel indicates the current state of synchronization between Video preview and playback data. The below picture indicates an unlocked state. This state allows for independent playback of video and motion data. This is always the initial state of an empty video channel,

k) The picture below indicates a locked state. This means that video and motion data are currently locked together with a fixed time-offset. This state automatically disables independent video playback. Video frames are now displayed according to ODIN’s current trial cursor; the selected time offset is locked in as a constant.

l) To configure the synch offset between trial and video data, ensure that the synch-panel is “Unlocked”. Once this is done, use the video controls to display a suitable video-synch-frame: some event that can be used as a reference to synchronize the two streams, like a clapper-board event. Subsequently use the controls to display the same synch-event in motion data in the main window (3D stick-figure views and graphs).

m) Notice that as you step through the video and motion data independently (when in the “Unlocked” state) the Synch Time Offset parameter (text-box) will change accordingly.

n) Upon viewing the synch-event frame in both the main panel and the Video preview panel, press on the “Lock” button in the Synch Panel. This will lock the synch time offset between motion-data and video. Notice that this will also grey out the Video playback controls to indicate that the video can no longer be played back independently and that the cursor is now driving video playback. You can now verify the synchronization between the two streams by playing back both streams using the Motion Controls panel.

O) Once you are satisfied that the two streams are properly in synch, and the Synch Time Offset is locked (greyed-out), click on OK to close this dialog. This will bring you back to the Video Trial properties dialogue containing all Video Channels associated with the current trial. Repeat the process to configure more video channels. Once you are done configuring all the video channels you want, remember to press OK on the Video Trial Properties dialogue and save your changes using the File menu (File->Save All). The Trial Properties dialogue displays information about the associated Video File and Synch Offset, along with the Synch events (in milliseconds) in the video and trial. Your trial now contains the required information to display contextual video along with motion data from the Codamotion system. This information is stored in the database, as long as you have select File: Save All, or if you exit with ‘Save & Exit’.

p) To clear a particular channel of its video file/trial synch information, simply click on the Clear button(X) which should bring up a confirmation dialogue indicating that doing so will reset the channel. Click on yes to proceed.

q) In case you want to clear ONLY the synch-offset data of a particular channel (retaining the video file information), simply follow step d) to open the channel editor, and click on the “Clear” button in the Synch Panel. This will display a warning dialogue to confirm your selection. Click yes to proceed. This will reset the synch offset to zero. Lock the synch and click on OK to save the changes.