| Standard Definition Services
Standard Definition (“SD”) channels are typically encoded by Bell ExpressVu at a resolution of 704x480i. (704 vertical lines x 480 horizontal lines, interlaced) Typically SD channels use the Musicam (“MP2”) audio format; however, many now carry an embedded Dolby Digital 2.0 or AC3 Surround Sound audio track.
| High Definition Services
High Definition (“HD”) channels carried by Bell ExpressVu at a resolution of either 1920x1080i (commonly referred to as 1080i) or 1280x720p (commonly referred to as 720p) which are two most common HD standards. Both of these resolutions assume a widescreen aspect ratio of 16:9. HD channels carry a Dolby Digital AC3 audio track.
| MPEG 2
MPEG-2 is a standard for coding video and audio information. The channels carried by Bell ExpressVu over the satellites located at 82 and 91 degrees are encoded in an MPEG 2 format and can be delivered to a broadcast distributor.
| MPEG 4
MPEG-4 is also a standard for coding video and audio information, and was introduced in late 1998. Bell ExpressVu encodes a large number of the services in MPEG 4 and can deliver the content to a broadcast distributor through a fibre optic network.
| Descriptive Video Service
Descriptive Video Service (“DVS”) is used to provide a description of the video for the visually impaired. Bell ExpressVu carries several channels with DVS.
| Headend Backup Service
The headend backup service provides your company with access to Bell ExpressVu's entire non-pay-per-view channel line-up in the event of an emergency or disaster at your primary broadcast centre. Please contact us for more information.