Bitrates will have to be lowered
By Steve Faguy
GATINEAU – Faced with escalating costs amid the coming 600 MHz repack of television stations, Corus Entertainment is proposing an “innovative solution” by using digital TV multiplexing to combine nearby Global TV over-the-air transmitters in eastern Ontario and the Okanagan region of B.C.
The CRTC published applications on Monday to remove seven retransmitters and instead put their programming as subchannels of another Global stations whose signal at least partially overlaps:
- CIII-DT-6 Ottawa (Global Toronto) would carry CKWS-TV-2 Prescott (Global Kingston)
- CHEX-DT Peterborough would carry CIII-DT-27 Peterborough (Global Toronto) and CKWS-DT-1 Brighton (Global Kingston)
- CKWS-DT Kingston would carry CIII-TV-2 Bancroft (Global Toronto)
- CHBC-DT Kelowna (Global Kelowna) would carry CHKL-DT Kelowna (Global BC)
- CHBC-DT-1 Penticton (Global Kelowna) would carry CHKL-DT-1 Penticton (Global BC)
- CHBC-DT-2 Vernon (Global Kelowna) would carry CHKL-DT-2 Vernon (Global BC)
In its application, Corus insists that “the proposed changes will not be perceivable by most OTA viewers.” For most of them, a simple rescan of their digital TV will pick up the same stations they used to, on new channel numbers ending in “.2” or “.3”.
For most of these areas, the transmitters being merged cover similar areas, and few covered by the transmitters they propose to shut down would lose access to their over-the-air signal. One outlier is the transmitter in Bancroft, Ont., which is about equidistant from Peterborough, Kingston and Ottawa. The Kingston transmitter covers only part of its service area, and Corus estimates that 14,597 people in its DTV urban contour and 173,460 people in its noise-limited bounding contour would not be able to receive it, though some of those would be able to pick up Global Toronto from its Ottawa or Peterborough transmitters.
The proposed shutdown follows an application last June by the company to shut down 44 Global OTA transmitters, including 24 transmitters of Global BC and Global Okanagan, Global Peterborough’s transmitter in Bancroft, and Global Kingston’s transmitter in Smiths Falls.
When it purchased the Global TV network from Canwest in 2010, former owner Shaw promised to use some of its tangible benefits funding to convert its rebroadcasting analog over-the-air transmitters to digital. Most transmitters proposed for shutdown have already been converted to digital.
However, the repacking of television stations to free up the 600 MHz band for wireless use means many station owners have to spend millions of dollars to change transmitters they replaced less than a decade ago, and unlike in the U.S., Canadian broadcasters aren’t being compensated for their costs. So, many smaller transmitters forced to change channels have instead been shut down. The transition schedule calls for Global Kingston’s Brighton transmitter to change from Channel 30 to Channel 23 between May 2 and July 3, with other changes following in the fall.
Corus has asked the CRTC for a quick decision so it does not have to go through with the channel changes. (The affected transmitters in B.C. do not have to change channels according to the plan.)
Besides the potential loss of signal, there is another technical drawback to combining these transmitters by multiplexing. DTV transmitters have a finite amount of data they can fit onto a 6 MHz channel, so Global is opting to have the main and subchannels in 720p resolution instead of 1080i. And for the Peterborough transmitter, which will have a main and two subchannels in HD, the video bitrate will be considerably reduced (6.46Mbps, versus 9.7Mbps per signal on the other stations and 18.5Mbps on non-multiplexed Global transmitters). Such compression may create artifacts visible to the viewer, particularly with fast-moving images.
Corus says it doesn’t believe this will be an issue.
“Prior to proceeding with the application, Corus conducted a series of tests at the proposed bitrates,” it writes in the application. “The conclusion of our engineering staff was the proposed changes will not be perceivable by most OTA viewers due to the genre of content typically broadcast on the channels (sports programming is most affected by compression) subject to the application and the quality of the apparatus planned to achieve the multiplex.”
Global TV carries very little sports programming.
Since the changes affect rebroadcasting transmitters and not any originating stations, Corus says there is no effect on programming. But correspondence with the Commission suggests there may be an impact on carriage and simultaneous substitution rules. Corus insists that it is multiplexing “transmitters” and not “stations” so there should be no change in how distributors carry their signals (including multiple Global stations in many cases) nor any changes in simultaneous substitution.
Corus stressed the application is contingent on carriage remaining unchanged. “If the Commission does not continue to mandate carriage of the services, Corus would be faced with the difficult decision of shutting down transmitters,” the company said.
The Part 1 applications are open for comment until April 1.
