Video Player Element

Modified on 2018/07/16 00:51 by Administrator Categorized as Base Elements, Elements, Visual Stimuli
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== Summary ==
{s:Element Info Panel
| title=Video player
| category=Visual Stimuli
| icon=[image|Element Icon|{UP(Video-player-Element)}Video-player-Element-Icon.png]
| author= OkazoLab
| addin= Base Layer
| scope= Parent event
| usage= Stimulus screen
| ownsnippets= None
}
== Properties ==
{|
|-
! Name
! Description                              
! Constraints
! Type
! On<br/>runtime<br/>change
|-
| colspan="5" bgcolor="#AADDDDD" | Playback
|-
| Playback Mode        
| Defines the playback mode for a video clip: 1) manual playback. 2) Single playback on the event onset (default mode). 3) Looped playback after event onset.        
| {s:atNormal}        
| stPlay..        
|  
|-
| Volume        
| Defines the volume of the audio playback, in percentages, from 0 (ground) to 100 (full)        
| {s:atNormal}        
| Int32        
|  
|-
| Balance        
| Defines the stereophonic balance of the audio playback, from 100 (most left) to 100 (most right)        
| {s:atNormal}        
| Int32        
|  
|-
| Start position        
| Defines the start position of video playback in percentages (0..100) to the total duration of the current video clip.        
| {s:atNormal}        
| Double        
|  
|-
| Current Position        
| Indicates the current playback position defined in percentages to the total duration of the current video clip. While a clip is playing, the position can be retrieved or adjusted to rewind the clip        
| {s:atNormal}        
| Double        
|  
|-
| Current Frame        
| Represents the current playback position defined by a number of video frame. While a clip is playing, the frame number can be read or adjusted to rewind the clip        
| {s:atNormal}        
| Double        
|  
|-
| Current Time        
| Represents the current playback position defined by a time (in ms). While a clip is playing, the property can be read or adjusted to rewind the clip        
| {s:atNormal}        
| clTime        
|  
|-
| Is Playing        
| Play Method        
| {s:atNormal}        
| Boolean        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Clip Info
|-
| Frame Rate        
| Original frame rate of the current clip in frames/second        
| {s:atStatus}        
| Double        
|  
|-
| Duration        
| Duration of the current clip in seconds        
| {s:atStatus}        
| Double        
|  
|-
| Number of Frames        
| Return a number of video frames in the current clip        
| {s:atStatus}        
| Int32        
|  
|-
| Frame Size        
| Original frame size of the current clip        
| {s:atStatus}        
| clSize        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Runtime Status
|-
| Start Time        
| The property stores the actual event time when the last playback started        
| {s:atStatus}        
| clTime        
|  
|-
| End Time        
| The property stores the actual event time when the last playback ended        
| {s:atStatus}        
| clTime        
|  
|-
| Is Triggered        
| If [Monitor Playback] property is true, this property indicates if the element has been triggered at least once after activation of the parent event. Triggering occurs each time when the playback ends.        
| {s:atNormal}        
| Boolean        
|  
|-
| Actual Framerate        
| Actual frame rate of video playback at runtime        
| {s:atNormal}        
| Double        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Material List
|-
| Selected Index        
| Defines an index of the selected library item in the list of this element        
| {s:atNormal}        
| Int32        
|  
|-
| Selected Item        
| Defines a name if the selected library item in the list of this element        
| {s:atNormal}        
| String        
|  
|-
| Item Count        
| Return the total number of material items in the list of this element        
| {s:atStatus}        
| Int32        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Visual Appearance
|-
| Alpha Masking        
| Defines, whether the visual content is used to create an opacity mask on the event surface. If masking is on, the content's pixel luminance (or, its inverse) defines transparency within element's viewport. The alpha masking allows, for example, create transparent holes on the event surface.        
| {s:atDesign}        
| Int32        
|  
|-
| AntiAliasing        
| if true, the rendered content will be antialiased for smoother visual appeariance. If false, rendering will be authentic to its source, e.g. a bitmap.        
| {s:atNormal}        
| Boolean        
|  
|-
| Position        
| Defines a position of the rendering viewport on the screen        
| {s:atNormal}        
| clPoint        
|  
|-
| Size        
| Defines a size of the element's rendering viewport on the screen        
| {s:atNormal}        
| clSize        
|  
|-
| Z Order        
| Indicates Z Order of the element on the given event        
| {s:atStatus}        
| Int32        
|  
|-
| Pivot Point        
| Defines alignment of the pivot point (or, element's position) relative to element's rendering area. The pivot point sets the center of element's rotation and scale directions.        
| {s:atNormal}        
| stAlig..        
|  
|-
| Visible        
| Defines whether the element is visible        
| {s:atNormal}        
| Boolean        
|  
|-
| Rotation        
| Rotation angle in degrees        
| {s:atNormal}        
| Double        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Effects
|-
| Transparent Color        
| The color of the original pixels of rendered content that will be set as transparent        
| {s:atNormal}        
| stColor        
|  
|-
| Transparent Tolerance        
| Tolerance ratio for choosing colors that become transparent. Zero means that effect is not applied, 1 denotes that all colors will become trasparent        
| {s:atNormal}        
| Int32        
|  
|-
| Color Mask        
| Produces a multiplicative combination of the original pixels
and the selected mask color (except the alpha channel).
 The effect emulates a look through a colored glass.
 White or transparent mask color dont change the original pixels        
| {s:atNormal}        
| stColor        
|  
|-
| Opacity        
| Opacity of the rendered content        
| {s:atNormal}        
| Int32        
|  
|-
| Contrast        
| Contrast of the rendered content        
| {s:atNormal}        
| Int32        
|  
|-
| Brightness        
| Brightness the rendered content        
| {s:atNormal}        
| Int32        
|  
|-
| Saturation        
| Saturation of the rendered content        
| {s:atNormal}        
| Double        
|  
|-
| Pixelation        
| Pixelation of the rendered content        
| {s:atNormal}        
| Int32        
|  
|-
| Blurring        
| The radius used in the gaussian blur of rendered content, as a pixel-based factor. The default is 0 which means no blurring.        
| {s:atNormal}        
| Int32        
|  
|-
| Scrambling        
|         
| {s:atNormal}        
| Double        
|  
|-
| Scrambling Grid Size        
| Defines a size of the scrambling grid        
| {s:atNormal}        
| clSize        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Positional Jitter
|-
| Reset Jitter Now        
| Runtime command that resets the positional jitter.        
| {s:atRuntimeAction}        
| Boolean        
|  
|-
| Current Jitter        
| Returns the current jitter        
| {s:atStatus}        
| clPoint        
|  
|-
| Jitter Range        
| Defines a possible range for the random jitter. The range is centered to the position of the element.        
| {s:atNormal}        
| clSize        
|  
|-
| Test Jitter        
| Click to test the current jitter        
| {s:atDesign}        
| Boolean        
|  
|-
| colspan="5" bgcolor="#AADDDDD" | Control
|-
| Is Enabled        
| If set to false the element is completely omitted when the experiment is run        
| {s:atDesign}        
| Boolean        
|  
|-
| Title        
| Title of the element        
| {s:atDesign}        
| String        
|  
|-            
|}
== ==
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'''Video Player Element''' is capable of showing videos in experiments.

{TOC}
== Description ==
Video Player element allows playback of video clips stored in [Material Library]. Different video formats are supported depending on installed codecs. The element provides all playback controls, time audit and various rendering options. Multiple clips can be loaded into element's list in order to form a stimulus set.
== Snapshots ==
{|
| [imageleft|Snapshot 1 <br/>|{UP(page - name)}*-sm.png |{UP(page - name)}*.png]
|| [imageleft|Snapshot 2 |{UP(page - name)}*-sm.png |{UP(page - name)}*.png]
|}
== Practical Use ==
The selected clip will be shown inside of a rectangular area on the screen and its appearance can be modified with properties values that you define for the Video element. For example, you can apply the visual effects for all video frames or adjust the size and rotation angle of the video window.{br}{br}Video element also can work with a list of video clips loaded from the experiment Library. It's handy for experimental scenarios where you need to present a random video clip at the same position on the screen. For example, you can define which video resources in the Library have to be in the element's resource list and choose an appropriate list index in the Video element at the start of each trial. All video clips will be rendered at the same position with the same size and visual properties that you have defined for the given Video element.{br}{br}Video element gives you a full control on the playback process: you can stop the playback, re-run it and rewind a video clip to the certain playback position.{br}{br}
=== Adding a video to an event ===

# Find the video clip that you wish to play and add it to the Material Library.
# On an event, click on "add element". From the 'MULTIMEDIA' category, select the '''Video player''' element
# Drag the media item from the material library onto the video player element in the left element plane. (Not onto the square on the event surface)
# Now you may adjust the size of the player by dragging the corners and you can adjust the relevant properties. (e.g Play back mode etc...)

== Notes ==

* By default, the playback start in Video element is synchronized with the activation of the parent event. You can use multiple Video elements in the same event but, in this case, they will be started one by one, usually with a neglible delay.

* Rendering of video clip frames is synchronized both with clip's timeline and the settings in your experiment. If you have enabled the synchronization with vertical monitor retraces in your experiment, each video frame will be also synchronized with it. The accurate timing of a video playback is not guaranteed and depends on a current computer load. However, you can always measure the actual duration of each frame in a playing video clip. Each time the new video frame is about to be rendered EventIDE calls OnPreparing snippet of the parent event. Checking the current time (e.g., by reading the Elapsed Time property of the parent event) inside of this snippet and comparing it with the previous call of the same snippet will give you a quite accurate measure of a single frame duration. If multiple video clips are shown simultaneously, then the same OnPreparing call can be made before rendering several frames in parallel.
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Video Player Element
