Does the HDTV stereo spec contain dolby pro logic information?

[yoda313]

So does the stereo in an HDTV broadcast contain Dolby Pro Logic information?

The reason I ask is sometimes a hdtv broadcast will contain only stereo and not 5.1 audio. Does this stereo allow for the Dolby Pro Logic processing? I'm not talking about DLP2 but the original Pro Logic. You know the one with the mono rear channel mix?

I recorded the first X Files movie on the A+E hd channel over digital cable and just finished watching it. It looked really good in widescreen. However I was disappointed that it was stereo only. So I decided to use the matrix mode on my sony 5.1 amp. I only have dlp 1 not two but it sounded farily good. I am wondering if this stereo broadcast contained any true dolby pro logic information.

Also - Is there any reason that hd channels on cable DON'T broadcast in widescreen? I mean whats the point of having a hd channel if you don't show it in widescreen? This particular movie was at least in widescreen. However I've seen movies like Harry Potter and the Matthew Broderick GODZILLA broadcast in full screen on the HD channel. What's the point???? I mean the HD channel is most likely only subscribed to by HDTV owners hence widescreen tv. Sure if you have DIGITAL CABLE you might have access to the hd channels but why broadcast full frame on the hd feed?????? It makes no sense to me. Just like not broadcasting a 5.1 signal.

Now heres another question - does it really save that much bandwidth to broadcast stereo instead of 5.1??? I mean its compressed audio so how much can be saved by going to stereo instead of 5.1???

Is there any pattern to the maddness of hd channels deciding between stereo and 5.1 or widescreen and fullscreen? It seems to me that the logical choice for a hd channel is to put a widescreen 5.1 feed on since that is what the PAYING customer is expecting.

Is this something I should send as a complaint to the cable company or directly to the cable channel? I mean would itbe better to complain to A+E and ABC Family stations about their broadcast or to the cable company that carries it????

Another oddity is that the sci fi channels hd feed carries the widescreen Stargate SG1 with 5.1 but its a letterboxed feed. That means I have to use the max overscan on my tv to fill the screen without borders. Whats the sense in that on a hd feed? Can it save that much bandwidth to send a smaller frame than to send a properly stretched 16:9 picture?

Is this just a case of the market adjusting to the new reality of high def? Is this a maturation process that will just take time for it to all gel? Also is this a doing of the studios not wanting to release near perfect albeit edited versions of their movies into copyable forms to the masses?????

If anyone has answers to this I'd be interested.

[Epicurus8a]

I didn't check all the details, but I suspect this is fairly accurate.
http://en.wikipedia.org/wiki/High-definition_television


Yoda, converting to HDTV is very expensive. Many small time broadcasters have simply gotten out of the business, and some larger broadcasters are having tough times because of the costs involved. Furthermore, advertising dollars are shrinking because viewers are turning to alternate methods of getting their programming. Eventually we might get "perfect" HDTV, but it will be a while. Meanwhile, engineers are already hard at work trying to make HDTV obsolete by improving the resolution, incorporating 3D, etc.

[yoda313]

@epicurus8a - thanks for the link.

I know conversion is expensive but I'm talking about already obtainable formats. Movies that are on dvd and bluray already have a widescreen version and a 5.1 audio track. How hard is it to pipe that through instead of the full frame stereo version?

I'm probably expecting too much. There are some stations that do just that. At least on the big movies. Not all do and that is a shame.

I just like to be able to watch a movie with a 5.1 track that I don't own on dvd. It's kind of neat to "cheat" the system and get the 5.1 track without physical media. Now dont' get me wrong I buy the movies that I really want so I don't have to wait for a broadcast. I'd just like all of the others to be on the same page.

[Epicurus8a]

DVD distribution is completely different....
Some program distributors are set up to distribute programming in full HD, and some aren't.
Yet relatively few broadcasters are set up receive/ broadcast everything in HD.

I know its frustrating, but you have to try and be patient for a few years. But even then, there are few guarantees.

BTW, HDTV stereo doesn't have to be pro-logic compatible. I'm fairly certain they could even be SD B/W with mono audio if they wanted. (Distributors, advertisers, and viewers might have a HUGE bone to pick with them, though.)

[Cornucopia]

As wikipedia mentions, ATSC/HDTV standards include Dolby Digital (AC3), MPEG Audio Layer 2 (MP2), and/or MPEG2 AAC audio streams. It doesn't mention anything about 1.0, 2.0 or 5.1 because that's internal to the audio stream, it really doesn't matter to the decoder as long as it recognizes the type of compression and can decode it. So all 3 of those channel types (and more beyond) could conceiveably be used.
Ok, assuming you use something like AC3 format, and it's encoded as 5.1. If the decoder end doesn't have the capability to decode fully the 5.1 stream, it'll downmix to 2.0. No problem.
Well, you must remember that from an outsider's view, 2.0 looks the same. so downmixed or natively encoded, a 2.0 stream can either be plain stereo, dual mono, binaural, etc. -or- Dolby Surround/ProLogic encoded. Because when a 4ch stream is matrixed into a ProLogic stream, it IS a 2ch stream. It's only whether the decoder has ProLogic decoding capability, and whether it is engaged manually or automatically. There is an AC3 flag that can be set to choose: DolbySurround/Prologic encoding vs. Plain stereo vs. Don't know/Not specified. If the flag is wrong and your decoder can manually engage it anyway, it doesn't matter. So in a sense, ALL stereo can support ProLogic decoding (whether it was meant to or not).

Scott

[yoda313]

@cornucopia - thanks. That makes sense. As I said the stereo did sound good for xfiles and the surround mode I used was halfway decent. I deleted the movie so I can't test it again. Next time I get a movie like that with stereo only I'll see how the basic prologic on my stereo handles it. I used a movie mode prologic setting instead of the standard pro logic. Again I have pro logic 1 not pro logic 2 on my amp.

[RabidDog]

Some might suspect a conspiracy but its probably merely a ****-up. Even in the future not all HDTV will be HD as many older classics, especially from Tv, are only available in SD. Some older films will never be properly transferred to digital formats.

[yoda313]

Well thats not that big of a problem but whats so hard about featuring a widescreen print on a hd channel even if its not high def? I mean yeah the regular channel could carry the full screen but if its on a "HD" channel doesn't it make more sense to pass a widescreen presentation even from a sd upconverted source???

[jagabo]

Well thats not that big of a problem but whats so hard about featuring a widescreen print on a hd channel even if its not high def? I mean yeah the regular channel could carry the full screen but if its on a "HD" channel doesn't it make more sense to pass a widescreen presentation even from a sd upconverted source???

The picture would be too blurry. I'd prefer to see it letterboxed an pillarboxed.

[Epicurus8a]

...whats so hard about featuring a widescreen print on a hd channel even if its not high def? I mean yeah the regular channel could carry the full screen but if its on a "HD" channel doesn't it make more sense to pass a widescreen presentation even from a sd upconverted source???

It's not so much a matter of difficulty. It's more a matter of $$$$$. At least one fairly large broadcaster I know of is in bankruptcy because of the tremendous costs involved, and I'm certain a lot of other broadcasters are hurting too. (Especially in this weak economy.)

After February 19th, 2009, the situation is bound to improve. But there are no guarantees of anything.