# Restrictions in EthoVision XT

In the following table you find a summary of the main restrictions in EthoVision XT.

General

Feature | Maximum number | Notes
Subjects per arena | 1 (Base module), up to 16 (Social Interaction module) | The limit of 16 subjects is set by the software. It may be difficult to discriminate between 16 different color marks depending on the light conditions. See Color markers We recommend to only use Tracking from video files when you track multiple subjects and multiple body points. The technical limit of 16 subjects per arena can be overridden in the software; contact Noldus for the possible solutions. Contact the Noldus Support
Arenas | 100 | With the Multiple Arena Module; One arena with the Base Module. Arenas must not overlap. The number of arenas does not depend on the number of cameras. You can have for example 96 wells in one camera image, or 16 arenas with 16 camera views (one arena per camera). When you combine tracking of multiple subjects (with colors) and multiple arenas, performance may limit the total number of subjects followed simultaneously.
Trials | 10000 |
Behavior types scored manually | 256 |
Hardware commands and signals | 1024 | With the Trial and Hardware Control Module
Arena Settings cache | 50 MB |
Heatmap dimensions (pixels) | 65536 |
Rows or columns in analysis results table | One million |
Free intervals | 2000 | See Free interval
Time bins | No restriction | If you create more than 1000 time bins, the group charts are not displayed.

Computer

Feature | Limitations | Notes
Computer type | Workstation | We recommend the use of Dell workstations especially when using multiple add-on modules (e.g. tracking nose-, center- and tail-base points in multiple subjects simultaneously) When tracking for more than 24 hours, restart the PC before a new trial. See Hardware
Video graphics card | NVIDIA, 4 GB or larger | If you opt to buy your own PC, it must have a stand-alone graphics card that supports Direct3D acceleration, We recommend NVIDIA video cards with a memory of 4 GB or larger. For tracking subjects with Deep learning, there are further restrictions. See Deep learning: Requirements
Processor and RAM memory | Intel | We recommend an Intel processor; for desktop PCs, a 32 GB RAM, and for laptops a 16 GB RAM.

See also

▪System requirements: Hardware

▪Ordering a PC from another supplier

▪More information on graphics cards (GPUs)

Video resolution, sample rate and trial duration

Feature | Maximum | Notes
Video resolution (camera image) | Depends on camera type | See Cameras supported by EthoVision XT
Video resolution (video file) | 1900 x 1200 | Higher resolutions, for example 4K video may work. Test a few sample videos and check for missing samples. Keep DDS selected in the Acquisition screen. See DDS (Detection determines speed)
Sample rate (live tracking) | 60 frames per second; it depends on the camera | See Cameras supported by EthoVision XT
Sample rate (tracking from video file) | Not specified | EthoVision XT can handle short video files with a frame rate of 1000, but that also depends on the video format. Test a few sample videos and check for missing samples before running the experiment.
Trial duration | 72 hours, but this depends on the tested setup | See Resolution, frame rate, and maximum trial duration

important When tracking from video files at high resolution and/or frame rate, always select DDS in the Playback Control window. This way EthoVision XT adjust the analysis speed to the time needed to analyze each frame without skipping frames. See DDS (Detection determines speed)

important When tracking for more than 24 hours, always reboot the PC after every trial to refresh the PC resources, the RAM specifically. Failure to do so could result in crashing, which can corrupt the experiment, or the recorded video.

Applications and add-ons

Feature | Maximum number | Notes
Multiple Body Point module (live tracking) | Four arenas per computer | In principle it is possible to track in more than 4 arenas, but it depends on the apparent size of the subjects in the video image (in pixels). Sample rate must be 25 samples/s or higher.
Multiple Arena module | 100 arenas | The number of arenas may be limited by other factors, for example the number of subjects in each arena and the tracking of multiple body points. Contact Noldus if you wish to work with more than 100 arenas.
Social Interaction module | 16 subjects per arena | If subject are unmarked, there may be subject identity swaps.
CognitionWall (Sylics) | Four arenas, only center-point tracking; up to 72 h recording | In case of recordings > 24 h, we advise to restart the PC after each trial. A workstation is required.
Behavior Recognition | Subjects: one per arena Arenas: one (live tracking), up to four (offline tracking) | Requires the Multiple Body Point module. Camera must be overhead. Camera frame rate must be at least 25 fps with no missing frames. Cannot work together with Deep learning-based tracking. The PC must be a workstation. See Behavior Recognition: Requirements
Deep learning for nose-tail base tracking | One or two subjects per arena (up to 4 arenas) | See Deep learning: Requirements

See also

▪Choose your camera

▪System requirements

▪The test environment