Blog Series: Lighting Education

Product Engineer Anthony Chiappone proudly stands in front of MVP panels.

Written by Product Engineer for CHAUVET Professional Anthony Chiappone.

Since video walls have become so desirable for large and medium shows, in my previous blog post, which you can read here, I explained why it is important to know when and how you should create video content. I focused on defining the resolution, the pixel pitch, and how these relate to video. Now, it is time to understand the application and the streamline process. Read on:

Application:
When selecting the design for the show, it is important to understand the desired outcome. If the intension of a video wall is to have live video (IMAG) played back on them, then you need to know the minimum viewing distance of the stage and also be sure to select an appropriate pixel pitch for this distance. In situations where you intend you play back motion graphics, the pixel pitch can be as low as 50mm, while still being effective. However, it is often good practice to use the following guideline when selecting video panels for an event where you intent to play back live camera/recorded footage.

Minimum viewing distance:
You should convert the pixel pitch to meters, and this is the closest that your audience should be at any time in order to comprehend what the video wall is playing back. For example, 12.5mm pixel pitch panels should only be seen at 12.5 meters, or 40 feet; although with increased distance the quality will look even better. This means that for indoor events in smaller venues, you would likely only want to use panels with pixel pitches of 3mm-12.5mm. And, for outdoor events with longer viewing distances, 12.5mm-40mm panels would be appropriate.

Indoor/outdoor:
If you are using the LED video panels outdoor, you should consider safety and strength of the structure you are hanging from. If you are using a temporary truss structure, then you should be concerned about the wind blowing over a solid wall. Therefore, the following words should be included in the product description: transparent, blow-through, and sometimes curtain (not used for flexible panels, but rather panels made of strips). This allows the wind to pass through the gaps in the panels, rather than blowing them over. This also is something that you should consider when selecting your pixel pitch, because larger pixel pitches provide greater transparency. Something else you should consider is the local weather. If you are using the video wall in an area that has frequent rainstorms, you should make sure that the panels have some degree of ingress protection (IP rating of 50 or higher). This does not need to protect against permanent outdoor installation. But, it should be sufficient for unexpected rainstorms.

How to streamline the process?
Keep in mind that many video playback software have the ability to grab certain portions of a single video file and send them to individual sections of your video wall. One of these is ArKaos MediaMaster Express. If you are using the Express version of the software, then you have the “cropping” tool. This is invaluable, as it simplifies the preproduction of your shows, and allows you to do most of your conversions to accommodate different pixel pitch panels in the same show, playing back the same content. With this tool, you no longer have to render custom video files 24-48 hours before the show time. Keep in mind that when you are using this technique, you should not apply any masks to the video content, if rendering it.

This miniseries on how to create video content should give you enough info to start rolling, but remember you have to conduct research on your own, as well, in order to keep up with the new technologies. Don’t be afraid to invest hours of practice and don’t forget to have fun!

Product Engineer Anthony Chiappone proudly stands in front of MVP panels.

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.

Be educated

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.