Here’s Part One of Two about the technology that transforms a blank flat panel screen into a communications dynamo! Just what you’ve been waiting for! (Hmmm?). It’s time for a wee bit of technical jargon, and it’s not going to hurt a bit. When it comes to digital signage (the moving kind), the one most confusing piece to translate from our world of static to the calisthenics of dynamic displays is: What resolution for content creation, and what settings for my screen will display it properly?
The easy part is the screen, really, if you can push some buttons enough times, maybe even break down and read the manual, you will find it. (Just practice at your own shop first, on an identical system, so you don’t look silly in front of your client.) As for content, however, you may feel like you’re jumping through hoops to get a handle on this, depending on the application for the content display and delivery. Is it for cellular delivery? Cabled? Wireless? Flash drive? A zone on the screen? HDTV? SD Kiosk? YouTube? Yep, it can be different for each!
First, the good news: If you (wisely) use a media house to create and render your content, you shouldn’t have to stress over square vs. rectangular pixels, frame rates, HD vs. SD, and all those other definitions. Now, the not so good news: You need to know this stuff, if you want to guide your clients through the conversation about content so you can order the right thing from your media house! So, here’s a little bit to get you started. The full blown Guide is available for those seeking their Digital Signage Certified Expert credentials from the Digital Signage Experts Group, if you order through SOSA.
To understand the current standards for HD Video and how it applies to digital signage, we’ll need to take a look at some basic terminology. To create the illusion of motion, video (just as with film movies) consists of a series of images displayed in rapid succession. Each single image is referred to as a Frame.
The most common frame rates include:
- 24p – NTSC 24 frames per second in progressive scan format
- 25p – PAL 25 frames per second in progressive scan format
- 30p – 30 frames per second in progressive scan format. This is the standard video rate for most common applications.
- 50i – PAL 50 interlaced fields (25 complete frames) per second (see “HD Frame Format” below). This is the standard video frame rate for PAL television broadcast.
- 60i – NTSC 60 interlaced fields (30 complete frames) per second. Technically, it is 59.94 fields, or 29.97 frames, per second. This is the NTSC standard for all television broadcast, DVD, and consumer camcorder.
- 50p/60p – 50/60 frames per second in progressive scan format, used in high-end HDTV systems.
- 72p – 72 frames per second in progressive format. This is a more-or-less experimental rate that is finding applications in high-speed video recording, which can then be played back at a lesser rate for ultra clear slow-motion video. It is also the current maximum rate available for WMV video.
HD Video File Formats:
Okay, here’s where it all comes together for useful applications … like digital signage. HD Video can be created and stored in many different file formats. The file format you choose should be based on the hardware and software that will be used to view it. For example, the digital signage software/hardware system you select may specify compatibility only with certain file formats for video. Here’s a list of the most common file formats and their most-used applications:
MPEG-2: Blu Ray Disc, DVD
MP4 (or MPEG-4), also known as H.264/AVC: Blu Ray Disc, Internet Streaming (YouTube, Vimeo, iTunes, etc.), local computer playback (Mac or Windows), mobile devices
WMV (Windows Media Video): Windows PC playback, Internet Streaming (although your video may be converted by the host)
MOV (QuickTime): Local computer playback (Mac or Windows), some DSLR (Canon) and camcorder native recording format
AVI: Windows computer video (massive storage required for uncompressed files!)
But wait … there’s more to the story. Next Post: HD resolution and the wonders of MP4! In case this is just not quite fun enough, LobbyPOP provides an excellent Guide for LobbyPOP Pros and Digital Signage Certified Experts. Just sayin…