[leopard]

I was wondering when and if HD CH Channel 521 on Rogers will finally be telecast in 5.1 DTS? I have noticed that most of their programming fills up the screen in HD on an HD capatible flat screen TV. The other problem is when they broadcast the same program that a U.S. Channel is carrying which is usually in 5.1 HD then it reverts back to audio on 2 front speakers and a subwoofer only. Could someone please answer this. Thanks in advance.

 

[Direc]

I'd recommend firing off the inquiry directly to CH as they might know if and when they will carry that audio stream.

 

[slipperbomb]

Does this happen on specific programming from CH or are they not passing 5.1 on anything? Dolby Digital does not always mean 5.1 surround sound, 2.1 is also part of the standard.

Many broadcasters will use an audio upmixer to mimic 5.1 for all programming whether it's really stereo, 2.1 or true 5.1. There are many reasons why they do this, but the main reason is so that at home your Dolby Digital light turns on and the viewer is happy! Perhaps CH is passing the native audio stream and the US station is using an upmixer?

There isn't a broadcaster that I know of that uses DTS though, Dolby Digital has become the industry standard for television.

 

[scampbell]

There isn't a broadcaster that I know of that uses DTS though, Dolby Digital has become the industry standard for television.

Do the cable boxes support DTS, should some station decide to start using it?

 

[slipperbomb]

Sorry to got off topic;

The ATSC broadcast standard for audio is AC-3 (Dolby Digital). DTS is used for cinema/DVD/BluRay. In theory I'm sure your STB could pass-though whatever audio signal is delivered, but as broadcasters transition to digital whether it be DTV or HDTV the standard they will be using is ATSC.

One reason Dolby Digital (AC-3) was chosen over DTS was because it uses less bandwidth. And since it uses less bandwidth, it costs less money for the broadcaster to transmit their signal via fiber or satellite.

Back on topic;

Unless it's happening with ALL programming on CH, it is most likely that they are passing the native audio stream (in this case 2.1) for the program while their US counterpart is passing the audio through an upmixer. I haven't watched CH in years, so this is just my best guess.

 

[ScaryBob]

Dolby digital can be any combination of 5 audio channels and/or 1 subwoofer channel. The most common combinations are DD2.0 (aka Pro Logic), DD3.0 (aka Pro Logic II) and DD5.1. I have also seen DD1.0 (aka mono) and DD 5.0 on broadcast signals. The correct way to handle the source audio is to pass on the DD audio from the source material. That could be anything. If the source is not DD, such as PCM or analog, the correct way to process it is to convert it to the corresponding DD format, usually DD2.0. Note that there is no way to differentiate between DD2.0 Pro Logic and stereo. IMHO that's a serious shortcoming in the DD standard.

As to CHCH's handling of audio. It's quite common for new HDTV stations and ISPs to just "get it wrong." It is often due to using misconfigured, outdated or inadequate equipment to process signals. They could assign a tech to monitor the audio and adjust the settings. That's something that does not get done on a continuous basis for obvious reasons. (I've seen cases where ISPs didn't even have the equipment to monitor DD audio.) Global HD's audio was a mess for a year and caused them to lose simsub rights due to complaints. The only thing I can suggest is to contact CHCH with your concerns and file a complaint with the CRTC if it make simsubs unwatchable.

 

[GeorgeMx]

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.

 

[james99]

In regards to CHCH, it has horrible HD. I would be more concerned about PQ than AQ.

It's impossible to watch a movie on this channel. I think VHS is better.

 

[ScaryBob]

I would guess that CH has a very limited budget. I doubt Global left them much in the way of usable HD equipment either.