Video Player

Category:

AddIn:

Scope:

Code Snippets:

Supports Material List:

Status Screen Widgets:

License:

Visual Stimuli

Base Elements

Local

Triggered

yes

Standard EventIDE license

In this article:

Introduction

The Video Player element enables precise presentation of video-based visual stimuli within EventIDE experiments. It supports flexible playback control, detailed runtime monitoring, and advanced visual effects, making it suitable for perceptual, cognitive, and affective research paradigms that rely on dynamic audiovisual content.

The element plays video clips stored in the Material Library and can handle multiple clips organized into a switchable stimulus set, ensuring accurate timing and reproducibility across trials.

Key Features

Flexible playback modes, including manual, single-play, and looped playback.
Precise runtime control over playback position, frame index, time, and volume.
Accurate timing audit, including start time, end time, actual frame rate, and playback duration.
Support for multiple video clips via the Material Library with runtime switching.
Advanced visual effects, including opacity, color masking, blurring, pixelation, scrambling, and jitter.
Direct rendering mode for high-performance stimulus presentation beyond standard event composition.
Spatial control, including position, size, rotation, pivot point, and Z-ordering.
Alpha masking support, enabling transparency effects and stimulus cutouts.
Runtime-trigger monitoring, allowing detection of playback completion for experimental control logic.

Properties

Name	Description	Constraints	Type	On runtime change
Settings
Playback Mode	Defines video playback mode: manual, single-play on event onset, or looped playback	Normal	stPlayMethod	–
Direct Rendering	Enables fast direct rendering bypassing normal event composition	Design-time	Boolean	–
Start Position	Start position of playback (0–100% of clip duration)	Normal	Double	–
Current Position	Current playback position (0–100%); can be read or adjusted at runtime	Normal	Double	–
Media Timeout	Maximum timeout for loading or seeking media (ms)	Design-time	clTime	–
Clip Info
Frame Rate	Original frame rate of the current clip (fps)	Status	Double	–
Duration	Duration of the current clip (seconds)	Status	Double	–
Number of Frames	Total number of frames in the clip	Status	Int32	–
Frame Size	Original resolution of the video clip	Status	clSize	–
Playback Control
Is Playing	Indicates or controls playback state (play/pause)	Normal	Boolean	–
Volume	Audio volume (0–100%)	Normal	Double	–
Balance	Stereo audio balance (left ↔ right)	Normal	Double	–
Runtime Status
Start Time	Event time when playback started	Status	clTime	–
Current Time	Current playback position in milliseconds	Normal	clTime	–
Current Frame	Current playback frame index	Normal	Double	–
End Time	Event time when playback ended	Status	clTime	–
Is Triggered	Indicates whether playback has completed since event activation	Normal	Boolean	–
Actual Framerate	Actual runtime playback frame rate	Status	Double	–
Material List
Selected Index	Index of the selected video clip	Normal	Int32	–
Selected Item	Name of the selected video clip	Normal	String	–
Item Count	Total number of video clips in the list	Status	Int32	–
Visual Appearance
Alpha Masking	Uses video luminance as opacity mask	Design-time	Int32	–
AntiAliasing	Enables antialiasing for smoother rendering	Normal	Boolean	–
Position	Screen position of the video viewport	Normal	clPoint	–
Size	Size of the video viewport	Normal	clSize	–
Z Order	Z-order of the element within the event	Status	Int32	–
Pivot Point	Defines pivot alignment for rotation and scaling	Normal	stAlignment	–
Visible	Controls element visibility	Normal	Boolean	–
Rotation	Rotation angle in degrees	Normal	Double	–
Effects
Transparent Color	Color set as transparent	Normal	stColor	–
Transparent Tolerance	Tolerance for transparency matching	Normal	Int32	–
Color Mask	Multiplies pixel colors with a mask color	Normal	stColor	–
Opacity	Opacity of rendered content	Normal	Int32	–
Contrast	Contrast adjustment	Normal	Int32	–
Brightness	Brightness adjustment	Normal	Int32	–
Saturation	Color saturation adjustment	Normal	Double	–
Pixelation	Pixelation intensity	Normal	Int32	–
Blurring	Gaussian blur radius	Normal	Int32	–
Scrambling	Proportion of scrambled voxels	Normal	Double	–
Scrambling Grid Size	Grid size for scrambling effect	Normal	clSize	–
Positional Jitter
Reset Jitter Now	Resets positional jitter	Runtime action	Boolean	–
Current Jitter	Current jitter offset	Status	clPoint	–
Jitter Range	Range of random positional jitter	Normal	clSize	–
Test Jitter	Tests current jitter configuration	Design-time	Boolean	–
Control
Is Enabled	Omits the element when false	Design-time	Boolean	–
Title	Title of the element	Design-time	String	–

Practical Use

The Video Player element is typically used as a primary visual stimulus in experiments involving motion, audiovisual perception, or naturalistic stimuli.

Technique 1: Trial-based video stimulus

This technique demonstrates how to present video stimuli, switch between multiple clips at runtime, and detect playback completion using proxy variables.

Add the Video Player element
Insert a Video Player element into the desired parent event that represents the stimulus screen.
Load video stimuli into the Material Library
Assign video clips to Video Player element
Drag and drop one or more video clips from the Material Library directly onto the Video Player element in the Element Panel.
The clips are added to the element’s internal Material List and can be accessed by Selected Index Property.
Configure playback mode
Set the Playback Mode property according to the experimental design (e.g. Single playback on event onset for automatic presentation, or Manual playback for full runtime control).
Select video clips at runtime
Create a proxy variable for the Selected Index property.
This allows the experiment logic or script to dynamically select which video clip from the material list is played during runtime (e.g. based on trial conditions or randomization).
Monitor playback completion
Create a proxy variable for the Is Triggered property.
This variable becomes true each time video playback reaches the end, allowing precise detection of stimulus completion for timing, flow control, or response evaluation.
Integrate with experiment flow
Use the Is Triggered proxy variable to:
- Advance to the next event using flow route condition
- Enable participant responses
- Trigger logging or adaptive logics.

Technique 2: Manual Playback and Dynamic Adjustments

Configure Playback Mode to Manual playback.
Add proxy variables to Current Position (or Current Time) and Is Playing properties.
Use proxy variable in code snippets to control playback.

//Example: restart video playback at the beginning of a  trial
CurrentPosition = 0;
IsPlaying = true;

For dynamic adjustments of the video you can use proxy variables linked to visual properties of the Video Player element, for example you can apply visual effects (e.g., blur, contrast, scrambling) dynamically to manipulate perceptual load.

Notes

For timing-critical experiments, consider enabling Direct Rendering to reduce rendering overhead.
The Actual Framerate property can be used to verify stimulus presentation fidelity.
Audio playback can be precisely controlled or muted using Volume and Balance.
Visual effects and jitter can be combined to create controlled stimulus degradation or uncertainty.
The Video Player integrates seamlessly with eye tracking, EEG, and behavioral response elements for multimodal experiment.
For short video clips and experiments that require precise frame-level control, deterministic timing, or variable playback speed, the use of the Video Sequencer DX element is recommended instead of the standard Video Player element.
Video Sequencer DX provides greater control over individual frames and playback timing, making it more suitable for paradigms that demand high temporal accuracy or non-linear video presentation.