Juno Awards Use Multichannel Dolby Digital On April 3, Canadian network CTV broadcast the 2005 Juno Awards—Canada’s music industry awards—from the MTS Centre in Winnipeg, Manitoba. The presentation, which included live performances by Randy Bachman, Billy Talent, k-os, kd lang, Sum 41, the Tragically Hip, and others, was broadcast nationwide for the first time in high-definition video accompanied by multichannel Dolby® Digital audio.
The program was distributed from CTV headquarters in Toronto. In HD form, it was available to subscribers of high-definition services, including the satellite service ExpressVu™ and various digital cable companies. The show was also broadcast in standard definition in every format: over the air, analog cable, digital cable, and direct-to-home satellite digital. Michael F. Nunan, Post Sound Supervisor at CTV Television, said, “Once the decision had been made that the show was going to be in high-definition this year, it didn’t require a great amount of effort to decide that it should be surround sound as well.” Ultimately, CTV engineers decided to mix in Dolby Digital 5.1 (without using the LFE channel), from which the stereo mix would be based. Two music mixers (alternating between acts) worked in 5.1, while a third mixer prepared an audience-only premix, also in 5.1. These signals were then sent to the main television mixer, who incorporated additional presentation elements, such as the podium mics, to the mix, as well as playback elements. These elements, which include the opening sequence and commercial bumpers, were a combination of standard stereo elements (from videotape machines) as well as premixed 5.1 elements (Dolby E streams from either Sony HDCAM™ machines or EVS servers). The main mix was prepared on a Calrec Alpha console in the Dome Majestic mobile truck. According to Nunan, “The 5.1 mix drained into DP571s for the Dolby E encode, and DP563s for the Dolby Pro Logic® II encode to Lt/Rt, using redundant pairs of each for primary and backup. We also had the mix going into a DP569 for the AC-3 encode, with all the requisite decoders for confidence monitoring: a DP572 for the Dolby E decode, and a DP564 that allowed us to hear the Dolby Pro Logic mix decoded, as well as performing a confidence decode of the Dolby Digital signal. There was also an LM100 ticking away in the background, giving us our loudness measurements.” Using a beta version of the LM100’s remote software, CTV engineers ran the logging software extensively over the two days of rehearsals, which allowed them to accurately determine proper dialnorm levels and author other metadata correctly for the telecast. In addition, for the Lt/Rt signal coming out of the DP563s, Nunan reentered it into the console for further processing. “CTV has very specific technical specs regarding levels in the delivery of a stereo mix,” he said. “So we took the signal coming out of the DP563 and put a limiter across it to guarantee that the Lt/Rt was exactly to our spec. Once we had the Lt/Rt, we distributed it back to all the mixers.” The mixers, in turn, listened to the Lt/Rt, making adjustments to the 5.1 mixes (without use of the LFE channel) on the basis of what they heard in the downmix. “The upside to having done an encode using DP563s,” said Nunan, “is that the downmix coefficients, such as the trim settings, already closely match the metadata we needed to author in the Dolby E and Dolby Digital streams for set-top box downmixing.” Aside from preparations made for successful multichannel mixing and transmission, the engineers rigorously tested for accurate audio-to-video sync before the telecast. “We’re going through so many stages,” said Nunan. “In addition to accounting for the latency inherent to the production environment, there’s still the Dolby gear, the MPEG encoders, the high-def ASI encoders, the transmissions themselves, and the decoding at the other end. There are so many variables, that even after trying to map out the accrued delay beforehand, we still needed to put a person in front of a lens with a microphone onstage to objectively find out where audio was relative to picture. There are so many hidden delays throughout the process of production, distribution, and transmission, that making it all look right when it finally hits somebody’s television was crucial.” The mix left Winnipeg on two HD paths: the primary path was fiber, which carried an ASI signal with two audio streams (a 5.1+2 Dolby E and an Lt/Rt signal as a backup). The secondary path was a KU-band satellite uplink that carried two audio streams: Lt/Rt and Dolby Digital. The final backup for the show was a downconverted SD signal that left Winnipeg on fiber carrying the Lt/Rt mix. • For additional information, see Broadcast Distribution with Dolby E, Surround Sound for Stereo Broadcasts, and Dolby Digital DTV and HDTV Transmission. |
