Editor's note: this article was written focused on VPX, but the general concept applies to VPX and VLX products, unless where specified otherwise.
VPX encoders and decoders provide a secondary stream that you can use for video preview in your control system touch panel, in IPBaseT manager, in a browser, or for other applications.
To utilize the feature within ReAX Core Studio, simply drag a "VPX/VLX Preview" object from your palette into your GUI. Select the new element and define the VPX or VLX IP address (you can define this using static text, or with a variable). Resize the window as necessary and you are ready to go. By default, this will display a 30fps streaming MJPEG preview for VPX, or a 1-10 frame streaming preview for VLX (based on last defined settings).
To use this in a 3rd party control system or application, you will use the URL of the streaming preview. The preview URL is available at:
http://[vpx-ip]:8080/?action=stream
Many 3rd party control systems are not capable of utilizing streaming formats, or are limited to their own proprietary streaming formats. For these, you will need to revert to a static image preview that gets refreshed periodically. The static image is a standard JPEG format, available at:
http://[vpx-ip]:8080/?action=snapshot
There are additional controls for the streaming and static previews. In VLX, you can set the quality and FPS in the web setup pages. For VPX, the following URL parameters can be used where applicable:
w (width, in pixels, of the preview)
h (height, in pixels, of the preview)
fps (frames per second of the preview 1-30)
For example, to show a 960x540 streaming VPX preview at 15 frames per second, use the URL string:
http://[vpx-ip]:8080/?action=stream&w=960&h=540&fps=15
If you wish to use these custom parameters in your Core Studio project, you can use an "iframe" object in a similar way as the native VLX/VPX preview. Add the iframe, select the element, and enter the full URL with parameters.
