Technology and Innovation

Analog Audio Level Matching

Problem: When installing and maintaining Ad-insertion equipment in a cable headend one of the most difficult jobs is to match the audio level of the local advertising to the level on the network.

Solution: DVC MultiChannel decoder/switches completely automate this process. The network audio levels pass through the switch unchanged, but are continuously measured so that when the local ads run, their level is matched automatically.

Double Buffered Z-Ordered Media Player

DVC has developed a Digital Signage application for Windows XP and Windows CE. Multiple areas of media content are on the screen, with each one potentially animated. Some need to be transparent - an animated logo or text has to 'fly' over the background. The screen content is assembled frame by frame in layers using the defined Z-order, into an off-screen buffer, and then displayed on screen with a clean transition. Each piece of content has a start time and a duration. When areas are scheduled to start at the same time, the Media Player must make sure they transition onto the screen at the same time. Different sections may animate at different frame rates. This software needs to be so stable that it runs continuously for a month at a time and handles errors, power failures, etc and detailed error handling reports sent to the central server.

High Quality Video Scaling

Problem: Some Digital Signage applications at DVC required direct connection of the LCD panel in TTL or LVDS. When the output resolution of the content does not match that of the Panel, the content needs to be stretched to fit. In an animated sequence or when playing video this can be very CPU intensive, and it produces a disappointing quality.

Solution: DVC developed a daughter board input with the LVDS LCD Panel output from the graphics chip, and a specialized video processing chip (similar to one found inside an LCD Monitor) to adjust the scaling to match the panel. The output quality is excellent.

Scalable Client Server Applications

Problem: Controlling a large number (thousands) of clients (media players) connected to a server over the internet causes some network and database traffic bottlenecks and performance problems. Connection via firewall is required. Remote diagnostics and Software Update capability is required for maintenance.

Solution:

• Extensive use of messaging for all communications and some intelligent handling of error conditions - dont let the queue content become too large when the network is disconnected, for example
• Use background transfer for the large video file transfers. Traffic is intelligently 'throttled' so other, lighter control traffic gets through. Allow retries and mid-file restarts in case of network intermittency.
• All traffic is initiated from the client, so if it is behind a firewall it has only outgoing IP traffic.
• DVC developed a secure (128 bit encrypted) custom remote management application, requiring connection on only port 443. A very low IP traffic connection is maintained every few seconds, so its possible to detect if a remote client is up and running or not.
• Custom Software update capability was developed. From one signal all clients can be instructed to connect,  download new versions and install themselves.

Very Low Power Battery Operated Digital Signage