More fun with technology! If you are up to date, you have followed these posts for a while. Our Part 1 of this two-part series on resolution is very important if you plan to use the information provided here, so give it a good read.
HD Resolution (or Frame Size):
There are 2 standard HD video resolutions: 1280×720 and 1920×1080 (width x height). Both are displayed in widescreen (16:9) image format and use square pixels (the tiny individual “dots” of color that collectively make up the full image). In contrast, standard definition (SD) video is a single resolution of 720×480 (for NTSC), using different pixel aspect ratios (non-square) to create either widescreen (16:9) or standard (4:3) images. The square pixel format yields a more consistent image on a variety of display types, whether it is a plasma screen, LCD, or LED TV (or computer monitor).
A third format exists, better known as HDV, that is common among consumer-oriented video cameras. This format is 1440×1080, and uses a non-square pixel size to render a widescreen image.
Now, factor in Progressive Scan (p) and Interlaced Scan (i) and entire world of bandwidth considerations comes into play. This post is just not big enough to cover the subject, so get the amazing Guide when you register to take the DSCE course.
Here’s the scoop in a nutshell: In a perfect digital world, we could say that it would always be better to display full frames in a progressive scan format, since each frame is a complete picture … and since current technology is certainly capable of keeping up with huge amounts of bandwidth, why would there be a need to compromise? Bandwidth is still an issue, however, especially in video transmitted over the Internet or through cellular service. The other issue is that many consumer or “pro-sumer” video cameras can only record high-resolution (1920×1080) video in interlaced scan format, since the hardware can’t support the higher bandwidth required by progressive. Don’t lose sleep over this – just use resources provided by your media house to guide in the right file rendering size.
The MP4/H.264/AVC format is capable of producing very high quality video in virtually any common resolution, including HD. It has been almost universally adopted as the standard for streaming video … and HD video in general. It is the preferred format for YouTube, Vimeo, and iTunes, and is the most common encoding method for commercial Blu Ray discs. The H.264 codec can also be used to encode MOV files. MP4 files can be played by the QuickTime Player on any Mac or Windows computer, the Windows Media Player on all Windows 7 based systems, and by most smart phones. Most of the currently available digital signage systems are compatible, too … WooHoo!
For these reasons, we at LobbyPOP prefer to render final video as MP4 files, to ensure compatibility across the spectrum, whether it’s playing from a locally-controlled digital signage player, remotely controlled system, Blu Ray disc, or streaming via YouTube. Of course, when the need arises, we can render in virtually any desired format … but generally speaking, an MP4 file will work for any computer or digital signage system.
There are many further details that may be discussed in the future, such as the accompanying audio formats for video files, bitrates, encoding profiles, etc., but it is too much to cover in this installment. Hopefully this crash course will help to gain an understanding of what HD video is all about.
For more: LobbyPOP provides an excellent Guide for LobbyPOP Pros and Digital Signage Certified Experts. Just sayin…