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Tutorial: Mixing, Switching, and Streaming Live with the Roland VR-3EX All-in-One A/V Mixer

In this tutorial we'll explore the robust audio and video mixing, switching, and live-delivery feature set of Roland's versatile next-generation 4-input VR-3EX, HDMI-capable A/V mixer.

USB Output for Streaming

The last thing I want to look at on the VR-3EX is the USB output. You can use it to capture, using the VR software from Roland (Figure 10, below), or you can use it for webcasting.

Figure 10. The Video Capture for VR software can be used to record the USB output with the Motion JPEG codec.

Before we proceed, it’s important to understand the difference between a square pixel and an anamorphic pixel. The NTSC standard is based on anamorphic pixels, which means that every pixel is non-square. In standard-definition 4:3, each pixel has a 0.9 pixel aspect ratio, meaning pixels are a bit taller than they are wide. Widescreen SD video has the same 720x480 resolution as 4:3 SD video does; the difference is that the pixels are now wider. A square-pixel equivalent needs to be calculated in order to properly webcast so that our images look correct anamorphically, and our viewers aren’t seeing squished or stretched images.

On Adobe Flash Media Live Encoder, 864x480 seems to work. Unfortunately, the input and the output don’t anamorphically adjust until we start webcasting. In Figure 11 (below), you can see the difference between the skinny version, which is anamorphically incorrect, and the proper wider-screen version.

Figure 11. Note the difference between the anamorphically incorrect version on the left, and the corrected (and streaming) widescreen version on the right.

A similar pixel-output problem happens using Ustream Producer, which is a white-label version of Wirecast. You’ll notice the same issue on Livestream Producer as well. You’ll need to go into the Asset Manager, select the VR-3EX, and change the device aspect ratio from the default square-pixel webcam to an anamorphic widescreen 720x486 input. Once you do this, the aspect ratio will appear correct.

So there you have it. This has been a tutorial for of the Roland VR-3EX A/V mixing console and USB-class streaming appliance.


For more information about Roland products contact this video’s sponsor,, at 800-323-2325.

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