Written by Product Engineer for CHAUVET Professional Anthony Chiappone.
Over the course of the last 18 months, LED video wall has become a necessity to large and even medium shows. With this growth, I’ve observed that video editors and video wall specifiers are struggling to keep up with the large variety of video panels in use, mainly due to a lack of communication, education and understanding the application. To give you the necessary basic information and gain confidence working with video, I have prepared a brief two-part guide to why and how you should generate video content.
Have the right questions—and answers too. As the video wall technician, the video editor will often ask you certain questions in regards to their content creation, such as, “What is the resolution of each section of video wall?” While this is important for a video editor and for you to know, it is equally important to be prepared and have the right answers to these questions.
- What is the pixel pitch?
- What are the actual dimensions/ratios of the video wall sections?
- How much space is between the panels?
- Should the video be rendered with a mask?
- Should the video be rendered as a single, large video or as individual video clips for each section of video wall?
- What is the minimum viewing distance?
These questions play a key role in content creation. It determines whether the video editor should design live video content, IMAG (image magnification), large or small text, or motion graphics.
Create according to resolution
It does no good to have high resolution graphics that look great on the computer screen, only to play it back on very low resolution, 50 mm pixel pitch curtains or LED mesh. And it would be equally wasteful to design very low resolution motion graphics for video wall that is capable of stunning, high resolution video content.
Understanding LED video walls vs. video projection.
One of the most deceiving content design obstacles comes when working with lower pixel pitch panels/curtains/mesh that cover a large area (outer dimensions). This means that you may have to design content of 1500×1200 and use a playback software, such as ArKaos MediaMaster Express to shrink it down to 150×120. This is something that is not true when using video projection, which is why you have the learning curve for LED video walls. This requires an understanding of the content creation, panel addressing/mapping software, playback software, and the collaboration of all to implement it successfully.
What is pixel resolution?
For the majority of video products, pixel resolution is all you need to know to create the video content, including LCD/plasma screens and projectors. But, LED video walls introduce a new factor: pixel pitch. This is a term that has long been used for computer displays, image scanners, and projectors—aka dot pitch, stripe pitch, or phosphor pitch. The pixel pitch is defined as the space between LEDs on a single panel. So, when you read in the specifications of a video panel that the pixel pitch is 12.5 mm, this means that the center-to-center spacing between LEDs is literally 12.5 mm. In most cases, the vertical and horizontal pixel pitches are the same. But, it may be different.
Now, why does this matter when creating video content? In the past, the pitches were mostly in micrometers. So, when you have two different displays, with content passing between both of them, the different is difficult to notice. But, when using LED video wall, the pitches are in millimeters, which is much easier to distinguish when building content for a large or small stage event.
In next month’s second part, I will explain how to create video content for a certain application and will get into streaming process. Until then, digest the knowledge I just shared with you and don’t be afraid to research on your own.