Knowledge Base

Acquire a Series of Trials Live + Save Video

Aim

To carry out video tracking in a live situation, for a number of times (trials), in a predefined list. Video is recorded.

Prerequisites

1. For general recommendations, see Acquire a Series of Trials - Live.
2. In the Acquisition Settings window, select both Track all planned trials and Save video.

Procedure

See the procedure Acquire a Series of Trials - Live. The differences are:

• Video for the current trial is being recorded to a file on the hard disk. Video recording starts at the start of the trial, not at the start of tracking.
• For each trial, video recording is stopped before the start of the inter-trial interval.
• Saving the video at the end of each trial takes time. The inter-trial interval countdown only starts after the video has been saved. For this reason, the total time between the end of the i-th trial and the start of the i+1-th trial may be longer than the inter-trial interval.

Record a Series of Videos, Then Acquire a Series of Trials

Aim

To record a number of video files while the tests are carried out. Video tracking is done in a later phase.

Important: With this method, Trial Control is not applied during video recording. This means that for example you cannot stop video recording automatically after 10 minutes. To stop video recording, do so manually (see below). Trial Control is applied in the second phase (acquire trial).

Prerequisites

1. For general recommendations, see Acquire a Series of Trials - Live.
2. Choose Acquisition > Open Acquisition. In the Acquisition Settings window, select Save video only, track later.
3. If no trials are planned, click the New trial button in the Playback Control window.

Procedure

Record a Series of Video Files

1. Choose Acquisition > Start Trial, or press Ctrl+F5, or click the Start trial button in the Playback Control window. The Video window says Recording video.
2. Release the animal in the arena.
3. To stop video recording, choose Acquisition > Stop Trial, or press Ctrl+F6, or click the Stop trial button in the Playback Control window.

Repeat the procedure for more video files.

Acquire a Series of Trials from the Video Files

1. In the Acquisition Settings window, select Track all saved video files.
2. Make sure that the video file is positioned at its beginning or, in any case, at the point where you want to start data acquisition. Optionally, select Detection determines speed in the Playback Control window to make sure that samples are not missed. See DDS (Detection Determines Speed) for the advantages of applying this option.
3. Choose Acquisition > Start Trial, or press Ctrl+F5, or click the Start trial button in the Playback Control window. The video is played forward and tracking takes place.
4. Acquisition stops automatically when the video file has reached the end and EthoVision XT automatically proceeds with the next saved video in your Trial List.
5. When all the videos have been analyzed, a message informs you that acquisition is done.

Notes

• If you wish to discard the tracks and re-do tracking from that video, see Redo a Trial.
• To make sure that tracking starts and stops at the correct moment in the video, you must define appropriate Trial Control settings.

Acquire a Series of Trials from Video Recorded with Other Programs

Aim

To carry out video tracking from a number of video files, recorded with a program other than EthoVision XT.

Prerequisites

For general recommendations, see Acquire a Trial from a Video File Recorded with Other Programs.

Procedure

1. Release the animals in the arena and record video to a digital media file using the appropriate hardware and software. We recommend using MediaRecorder. At the end of this step you should have a number of video files.
2. Make a Trial List for batch acquisition and add one video for each trial in the list. See Prepare the Trial List for Batch Acquisition.
3. Acquire a series of trials from the video files:
   1. Choose Acquisition > Open Acquisition. In the Acquisition Settings window select Track all planned trials. The name of the first planned trial in the Trial List appears in the field next to Trial and the associated video file opens in the Video window.
   2. Make sure that the video file is positioned at its beginning or, in any case, at the point where you want to start data acquisition. Select DDS in the Playback Control window to make sure that samples are not missed.
   3. Choose Acquisition > Start Trial, or press Ctrl+F5, or click the Start series button in the Playback Control window.

Notes

• To make sure that tracking starts and stops at the correct time point, you must define appropriate Trial Control settings.
• If you stop batch acquisition manually, all trials acquired up to that time are saved, including the current one that was interrupted. Click the Start series button again to complete the series. If necessary, redo the trial that was interrupted. See Redo a Trial.
• If you wish to track data once again from that video, add a trial and follow the procedure for single trial acquisition. See Acquire One Trial.
• The lighting conditions could be different between the start of subsequent trials. When using subtraction or differencing for subject detection, you can update the reference image based on the first video frame, keeping the reference image matched with the current conditions. See Use First Frame of Each Trial in Optimize the Reference Image > The Reference Image.