Polybench® Reference
Allows to view live or stored video frames from a video input operator

Video Viewer

Overview

The Video Viewer is used to view live videos as well as recorded videos. If a stored video stream is connected to the viewer, a scrollbar is displayed below the video.

Operator ports

Input video In: Specific sample type, see below.

Paired User Interface Object

This operator is loaded simultaneously with a user interface object. The user interface object can be moved to another page, and would normally be displayed in the end-user application. The operator and this user interface object can never be separated. If you delete the operator, the user interface is deleted automatically as well. Note that you cannot delete the user interface, only the operator symbol!

Properties

Find more information about changing properties here: link

ScrollbarVisible
type: True or False
Set to true if the scrollbar should be visible below the video viewer, or false to always hide the scrollbar.
Select one of those presets:
True or False
True may also be read like 'yes' and false like 'no'


Stretched
type: True or False
Set to True if the video image should be stretched to the size of the view box, or False if the original aspect ratio should be used.
Select one of those presets:
True or False
True may also be read like 'yes' and false like 'no'

Note that is the original aspect ratio is used, that if the video viewer size has another aspect ratio, that you will then see black bars left and right, or at the top and bottom.

SyncID
type: See description
Synchronization code to synchronize the frame cursor with other viewers


Caption
type: Word or phrase
The name of the object in the project. This name must not contain '.' or '$' characters.

Every object has the Caption property. This property is very important, because it is the name by which Polybench recognizes this object.
It is allowed to give multiple objects the same name, as long as the objects are of the same type. In that case, a reference to this caption includes all the objects with the same caption.
In Polybench, every object can be addressed by an Address specifier, which starts with the dollar sign, for example: $My Page.My Object. 'My Page' would be the Caption of a page, and 'My Object' the Caption of an object on that page.

Documentation
type: See description
Optional documentation of this object.

It is good practice to write in short notes why you have used this object, and why its properties are set the way they are set. If this object is an operator, the Documentation text is displayed below the operator symbol.

Variable Parameters

Find more information about Variable Parameters here: link

TimeSyncOffset
type: See description
The time offset of the data cursor for this viewer. If you link multiple data review components together (using a SyncID), then this viewer may show a time offset. The time is expressed in hour:minute:second, or in seconds, and can also be negative.

You may enter a time, for example 0:0:1.2 for 1.2 seconds, or 0:1 for one minute, or you may enter a value in seconds, for example -0.3.

You need to use this variable, if you try to synchronize signals and videos in review or replay modes and if you then want to use the scrollbar to scroll to a video frame and any other reviewers that are linked to the same data cursor. So, if you move the scrollbar of the video viewer, then the time of the current frame is sent to other viewers and replayers, so that they can show data of the same moment in time. But if there is a shift in time between the different data sources, wrong data is shown. In that case, you may need to adjust the time of this viewer by using this variable parameter.

FrameTime
type: See description
The time of the frame that is currently shown in the viewer. The time is displayed in time format and has a maximal resolution of 1 millisecond.


FrameTimeSeconds
type: See description
The time of the frame that is currently shown in the viewer. The time is displayed in seconds and has a maximal resolution of 1 millisecond.

Details

Limitations

Note that the same video can only be shown once on screen. If you would connect two Video Viewers to the same video source (which is also allowed for signal viewers), then only one of both will show the video.
However, if both viewers are put on different pages, then on both pages the video will show. So, as long as you do not want to see the same video twice on screen, you can connect as many video viewers to a video source as you want.

Note that it is possible to show two different video sources simultaniously on one screen.

User Interface Object on Printable Pages

The user interface of this component will be printed on a report, if it is put on a Printable Page (see link).

Behaviour in relation to the data cursor in reviewed data

This object reacts on a change of the central Data Cursor of a group of synchronized objects. This means that if this object has the same SyncID as the object that changes the Data Cursor, then this object will change its state accordingly. For more information see also: link.