Content Formats – Part II
May 21, 2006
MPEG-4
MPEG-4 is an advancement over the MPEG-2. The new standard has the advantage that good quality video can be properly encoded at relatively low bit rate. MPEG-4 is the basis of the DivX codec, one of the most popular video format used on the Internet.
MPEG-4 is widely used on the Internet for its efficiency in transporting over the network. MPEG-4 video is often encoded at 1 to 2 Mbps, or 1/8 to 1/4 MB per second (128 to 256 kbps). A 1 GB memory card easily holds 1 hour of MPEG-4 video. Transmitting a 1-minute MPEG-4 content on the 512 kbps xDSL takes 30 to 60 seconds. This makes frequent content updates feasible.
To be continued…
Content Formats, Part I
May 16, 2006
Digital signage contents are often created in the following formats:
MPEG-1/2
MPEG-1 and MPEG-2 are two of the most common video compression formats in use. They are often used to store and deliver video content on digital signage networks. MPEG-1 is the storage format for VCDs and is rarely used today. MPEG-2 performs better than MPEG-1 at higher bit rates, and is the video format for DVDs.
MPEG-2 media clip are typically encoded at 4 to 8 Mbps, or 0.5 to 1 MB per second of video content. Higher bitrate yields better video quality. A 1 GB memory card holds about 15 to 30 minutes of MPEG-2 video.
Long clips of MPEG-2 is not suitable for delivery over the network today. It takes a typical 512 kbps xDSL connection 8-16 minutes to deliver just one minute of MPEG-2 video.
To be continued…
This is Part II of the Categorization for Digital Signage Endpoint Devices article.
Non-PC / MPEG-2
Most non-PC products support MPEG-1/MPEG-2 decoding from a CompactFlash (CF) memory card. A 1 GB memory card stores approximately 30 minutes of MPEG-2 video. These are the simplest form of a digital signage media player available today.
Non-PC / MPEG-4
More advanced non-PC products support MPEG-4/DivX. These have an advantage over the MPEG-2 players in that MPEG-4 files occupy less storage space. A 1 GB memory card usually supports 60 minutes of MPEG-4 video. These are also low cost, but extensive “sneaker net” delivery cost may occur.
Non-PC / Set-top Box
Sometimes called “IPTV” solutions, these are low cost consumer set-top boxes that are used to deliver cable TV to home. They often support MPEG-2 video streaming via Internet without using a local CF card. The benefit of a set-top box is that it solves the problem of relying on the sneaker net. The downside is that most set-top boxes require a live Internet connection with large bandwidth (4 to 8Mbps per channel) to the media server to stream media files, and creates a large server bandwidth requirement that results in great connectivity costs.
Non-PC / Interactive
Some non-PC solutions also support interactive control (touch screen, bar code scanner, etc.) in addition to video playback. They support a restrictive form of kiosk application yet provide superior reliability to PC-based solutions.
Non-PC / HD (High Definition)
The more advanced non-PC solutions support the playback of HD contents and often in multiple zones. These devices perform very closely to PC-based solutions while continue to provide simplicity and reliability. These devices are also usually network controlled by a management software.
Endpoint devices are the media players at the end of the network connection driving display devices (TFT-LCDs, plasmas, LED walls, etc.). They are implemented in various technologies.
Wintel PC
Digital signage systems today are often implemented using ordinary desktop IBM-compatible PCs running Microsoft Windows. On top of this, a media player control software is run to play back media files according to a schedule. The main strength of the Wintel PC is flexibility. The main weakness is lack of reliability, as Wintel platforms are known to crash in front of the captive audience.
Linux PC
The Linux PC is a variation of the Wintel PC, running the open source Linux operating system instead of Microsoft Windows. A media player control software running on top of X-windows is often the solution. The upside of Linux PC is a reduction of cost (free operating system) and, some believe, improved reliability of the operating system. The downside is that it still runs on ordinary PC hardware and can be prone to reliability problems.
Mac PC
Another variation of the PC solutions is the Mac PC. With the Mac mini’s introduced at $499 with full media playback capabilities, the Mac PC is an attractive alternative to the Wintel PC, especially for the art savvy content designer. The plus of the Mac PC is a compact form factor and higher level of visual display capabilities. The minus of it is again lack of robustness being a consumer-grade solution.
Software
Often a endpoint technology comes as a software package only. The software runs on one of the hardware systems. The benefit of having a pure software solution is the choice of hardware is open to the integrator and cost can be easier controlled. However the risk here is that a software/hardware combination that is not certified by a vendor can often cause unforeseen problems unless it is well tested before installation.
Non-PC
A number of non-PC solutions exist today, running on various non-Wintel, RISC-based platforms. IC vendors including ESS, Sigma Designs, TI, AMD, Intel all offer solutions that are capable of handling digital signage in a dedicated hardware. The pros of a non-PC solution is by far reliability and often size. However the cons are that display features are often limited to video playback only and can be hard to integrate with real-time reporting systems (arrival/departure information, currency/interest rates, etc.).
Variations of non-PC solutions are described in detail in Part II of this article.
Inscriber Infocaster
May 7, 2006
Webpavement Sign Server
May 7, 2006
Webpavement Sign Server
Web-based digital signage platform server
Webpavement Sign Host
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Navori
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Wirespring FireCast
May 7, 2006
Scala
May 7, 2006
Scala
PC-based content authoring software, player, and network management software.
The Digital Signage Technologist 