Dolby audio has two principal versions used in the broadcast industry. In the production and master control environments, the professional standard known as 'Dolby E' is used by some broadcasters. The standard is capable of 5.1 channels in the same digital audio stream as conventional, uncompressed PCM stereo audio. The E standard allows a broadcaster to upgrade a digital stereo facility to 5.1 without replacing all the equipment. The Dolby E stream can also be recorded on a digital stereo pair of a studio VCR. On a VCR with two stereo pairs, one typically carries a conventional L/R stereo mixdown while the other carries Dolby E. Some professional HD VCR formats can handle 8 independent channels which allows room for 5.0, a stereo mix and described video. The Dolby .1 channel can be synthesized from the other 5 channels before transmission.
The other Dolby standard is consumer Dolby as used for DVD, Blu-Ray and ATSC transmission. The consumer Dolby stream is generated at the output of the master control from either 6 separate audio channels or a Dolby E stream. The main difference between the two standards is that Dolby E is designed to allow repeated encoding and decoding with minimum signal degradation while consumer Dolby is intended for one encode/decode cycle in signal distribution to the end user.
Network audio distribution to affiliate stations varies by network. Some use 6 independent audio channels while others use Dolby E. Fox in the US uses a completely different approach than other networks with the complete video and audio signal delivered as MPEG2 ready to feed the ATSC transmitter. In this case the consumer Dolby 5.1 is generated at the network uplink. The local affiliate does not require any 5.1 audio capability for network programming as they switch MPEG signals between the local encoder and the network satellite receiver.
With respect to CHCH, at this point it appears that they don't have any 5.1 capability and simply use standard stereo audio. Complaining to the CRTC about stereo versus 5.1 probably won't get very far as they allow mono substitution over stereo in the analog world.