System Connectivity:
An application processor solution that supports a minimum of two USB 2.0 Host ports and has a PCI express interface provides use flexibility. It is important that the USB ports are fully compliant with EHCI and OHCI specifications. In addition, the PCI Express Host needs to be compliant with PCI Express Specification, Rev 1.1 in order to enable the addition of networked storage and a Wi-Fi sub-system, through companion chips.
A network application processor for digital signage players must factor in both wired and wireless specifications that are ideal for the industry. There are various key specifications that will enhance the solution under design and reduce design time. For wired networks, we’ve indicated that 10/100/1000 Gigabit Ethernet support is important and that it should be fully compliant with IEEE 802.3 specifications. Hardware acceleration provided by the network application processor for TCP/IP/UDP processing will enhance performance and reduce the load on the CPU. For wireless networks, 802.11g/802.11n wireless support through PCIe or a Wi-Fi Adapter will provide better throughput and reduced CPU load. There should also be support for IP addressing, whether static or DHCP.
Display Interface:
The display interfaces built into the network application processor in use should include support for connecting to LCD / Plasma displays, through LVDS FPD Link / RGB / DVI interfaces. Most signage solutions vendors support a portfolio of products with a mix of the following display resolutions:
o QVGA (320×240)
o VGA (640×480)
o SVGA (800×600)
o XGA (1024×768)
o 720p(1280 X 720)
o WXGA (1366 x 768)
o UXGA (1600 x 1200)
o 1080i/1080p (1920 x 1080)
Medium end signage players typically support up to (1280 X 720) resolutions or 720p. Higher end signage players support up to 1920 x 1080 (1080i or 1080p). Support for Clone Mode is also ideal to enable playing two different videos.
The AV playback formats that are supported must also be comprehensive. Here’s a list of those that must be supported by the network appliance processor for the widest appeal:
Video:
- MPEG-1 (VCD) and MPEG-2 (SVCD/DVD/DVB) video
- MPEG-4 ASP in all variants including DivX, Xvid
- MPEG-4 AVC aka H.264
- Windows Media Video 7/8 (WMV1/2)
- Real Video 1.0, 2.0 (G2)
- DV video
- MJPEG, AVID, VCR2, ASV2 and other hardware formats
- FLI/FLC
- VOB
Audio:
- MPEG layer 1, 2, and 3 (MP3) audio
- AC3/A52 (Dolby Digital) audio (software or SP/DIF)
- AAC (MPEG-4 audio)
- WMA (DivX Audio) v1, v2
- RealAudio: DNET and older code
NEXT: Software Design to Tie it All Together
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