SDTV dolby prologic & dolby digital

[jason887]

Does anyone know why only ABC, Nine & Ten standard definition are the only channels to have dolby prologic?, Seven, ABC2 & SBS only offer stereo, however ABC2 is probably restricted by bandwidth.
Also seven HD offers only dolby prologic however during the HD loop you can get dolby digital 5.1 surround. Why is it not possible for the networks to broadcast in dolby digital 5.1 when available. This is from a SDTV set top box in Brisbane. Is it any different in other states?

[Peter Tate]

not sure but I find the DD is not too good for realiablity

Some decoders i note drop out. Haven't sussed it out fully yet. So it stays
on the standard setting for now.

--
Station X - Gold Coast Australia
"The happiest mix from yesterday and today!"

Website : http://www.stationx.com.au
Listen : http://www.stationx.com.au/downloads/serverlinks.m3u

"jason887" <jason887.1n494z@no-mx.forums.eyo.com.au> wrote in message
news:jason887.1n494z@no-mx.forums.eyo.com.au...
>
> Does anyone know why only ABC, Nine & Ten standard definition are the
> only channels to have dolby prologic?, Seven, ABC2 & SBS only offer
> stereo, however ABC2 is probably restricted by bandwidth.
> Also seven HD offers only dolby prologic however during the HD loop you
> can get dolby digital 5.1 surround. Why is it not possible for the
> networks to broadcast in dolby digital 5.1 when available. This is from
> a SDTV set top box in Brisbane. Is it any different in other states?
>
>
> --
> jason887

[Anthony Horan]

On Thu, 7 Apr 2005 21:07:19 +1000, jason887 wrote:

> Does anyone know why only ABC, Nine & Ten standard definition are the
> only channels to have dolby prologic?, Seven, ABC2 & SBS only offer
> stereo, however ABC2 is probably restricted by bandwidth.

Ah, the common misconception strikes again :-)

Dolby "ProLogic" is non-existent as an encoding/transmission format. It's a
marketing buzz-word for a particular surround decoding method.

Dolby SURROUND is the correct terminology, and all programs mixed in
surround, whether flagged as such in the digital stream or not, are easily
decoded in surround by hitting that button on your decoder that's marked -
yes, you guessed it - "surround" :)

Dolby surround (or "Prologic" if you prefer) does not require any
additional bandwidth to transmit. The difference between a surround-flagged
audio stream and a stereo one is one single digital bit. That bit is set
only for the convenience of those who have decoders that recognise it.

> Also seven HD offers only dolby prologic however during the HD loop you
> can get dolby digital 5.1 surround. Why is it not possible for the
> networks to broadcast in dolby digital 5.1 when available.

Agreed there; I'd love to see some 5.1 audio on SD.


- Anthony

[Ozdude]

"jason887" <jason887.1n494z@no-mx.forums.eyo.com.au> wrote in message
news:jason887.1n494z@no-mx.forums.eyo.com.au...
>
> Does anyone know why only ABC, Nine & Ten standard definition are the
> only channels to have dolby prologic?, Seven, ABC2 & SBS only offer
> stereo, however ABC2 is probably restricted by bandwidth.
> Also seven HD offers only dolby prologic however during the HD loop you
> can get dolby digital 5.1 surround. Why is it not possible for the
> networks to broadcast in dolby digital 5.1 when available. This is from
> a SDTV set top box in Brisbane. Is it any different in other states?

Stereo *is* Dolby Pro Logic (II). It's a matrixed surround scheme and it's
encoded into the stereo signal, that's why you see "Stereo" as the carrier
state on your STB. Don't worry -connect it to a DPL(II) decoder and you'll
have the surround in Pro Logic.

DD5.1 was mandated originally as the default audio standard, but someone (A
certain ludite minister) paniced at the last minute due to propaganda from
certain involved persons and made Musicam (MPEG) the default sound. No need
to worry here though as there is only rare true 5.1 transmission on Oz DTV.
The MPEG isn't cutting off at 15KHz like A2 FM analogue stereo does, so you
get the same fidelity, you just get 3.2 sound at best instead of 5.1.

My only personal bug-bear about Musicam audio is the inherent decoder issues
using ProLogic. You don't get discete 5 channel sound and if the bass has an
event the centre will sometimes suffer, also in DPL the rears are mono and
limited to, at best 11KHz or something like that, the standard is to roll
off at 7KHz (hardly Hi-Fi!).

I believe DPLII goes a long way to addressing the rear channel and steering
issue (full range and seperated left and right) and I'm not sure what what
this updated decoder does with the centre. There is also a newer DPLIIx 7.1
decoder out and about but I haven't seen this on any receivers in Oz
personally.

Just turn your DPL on to your stereo inputs from the DTV stations and enjoy
surround sound.

Oz

[wh00t-at-me]

"Anthony Horan" <anthonyhoran@hotmail.com> wrote in message
news:1q4w8pwh7aqw3$.612fp2882ew9.dlg@40tude.net...
> On Thu, 7 Apr 2005 21:07:19 +1000, jason887 wrote:
>
>> Does anyone know why only ABC, Nine & Ten standard definition are the
>> only channels to have dolby prologic?, Seven, ABC2 & SBS only offer
>> stereo, however ABC2 is probably restricted by bandwidth.
>
> Ah, the common misconception strikes again :-)
>
> Dolby "ProLogic" is non-existent as an encoding/transmission format. It's
> a
> marketing buzz-word for a particular surround decoding method.

Why is it a misconception? The TV viewer doesn't have anything to do with
the encoding method. The viewer uses Pro Logic so the use of "Pro Logic" is
correct as far as they're concerned. Even Dolby interchanges the terms
because they're both parts of the whole process.

[Greg Alexander]

wh00t-at-me wrote:
> "Anthony Horan" <anthonyhoran@hotmail.com> wrote:
> > jason887 wrote:
> >
> >> Does anyone know why only ABC, Nine & Ten standard
> >> definition are the only channels to have dolby prologic?,
> >> Seven, ABC2 & SBS only offer stereo, however ABC2 is
> >> probably restricted by bandwidth.
> >
> > Ah, the common misconception strikes again :-)
>
> Why is it a misconception?
> The viewer uses Pro Logic so the use of "Pro Logic" is
> correct as far as they're concerned.

I can see why _I_ think it's a misconception.

Firstly, so what if the viewer is correct as far as they're concerned?
If they're not speaking the same language as others then there's some
miscommunication bound to happen.

Secondly Dolby has 2 technologies that are relevant to this discussion
- Dolby Digital (surround) and Dolby ProLogic (surround). Most shows
have dolby prologic built into their stereo signal now.

Basically if a show is broadcast in stereo and you have a ProLogic
amplifier you'll get ProLogic surround. Not Dolby Digital, but Dolby
ProLogic. I'm not sure if Seven could remove that even if they wanted
to!

For Dolby Digital it's a different issue. It'd be great if SDTV
broadcast 5 channels of Dolby Digital. Until then I guess we're stuck
with ProLogic.

Greg

[jason887]

For Dolby Digital it's a different issue. It'd be great if SDTV
broadcast 5 channels of Dolby Digital. Until then I guess we're stuck
with ProLogic.

I do agree there. I have seen 5.1 dolby digital overseas on SDTV broadcasts. It's a shame they don't utilize it here when it every bit possible, for most primetime shows anyway. If the networks offered DD5.1 on SDTV, it would be great marketing for SDTV boxes and sets. Foxtel had quite some success when they promoted that Foxtel box office offered DD 5.1 on their movies. It could very well be one of the reasons why digital hasn't taken off in popularity as the networks had expected. Unfortunately dolby digital 2.0 (which is the current audio signal available), even when decoded into dolby prologic II surround just doesn't have the dynamic range and quality of DD 5.1.

[Michael]

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112918160.582229.8820@l41g2000cwc.googlegrou ps.com...
> Firstly, so what if the viewer is correct as far as they're concerned?
> If they're not speaking the same language as others then there's some
> miscommunication bound to happen.

Exactly.

> Secondly Dolby has 2 technologies that are relevant to this discussion
> - Dolby Digital (surround) and Dolby ProLogic (surround). Most shows
> have dolby prologic built into their stereo signal now.

No, as Anthony correctly pointed out, they're quite often encoded with Dolby
Surround. Pro Logic, Pro Logic IIx, DTS Neo etc. are decoding methods and
cannot be broadcast.

[Greg Alexander]

I wasn't aware that the signal encoding and the decoding method had
separate names.
I'll assume Anthony is correct here. So you and he are saying that the
stereo signal is encoded with Dolby Surround, and decoded by Dolby
ProLogic (or other related system).

That's fine. And this is quite separate from Dolby Digital 5.1 Channel
Surround (what's its official name?)

We know that Dolby Digital CAN be 2 channels. We get 2 channels
(Stereo) on our SDTV at the moment, and that stereo signal most likely
has Dolby Surround which your ProLogic decoder can play.

However, Dolby Digital can also broadcast in 5 channels, and the
surround is of far higher quality (but if someone only has a ProLogic
decoder it will make no difference and just use the 2 channels for its
source).

[Greg Alexander]

Greg Alexander wrote:
> (but if someone only has a ProLogic
> decoder it will make no difference and just use the 2 channels
> for its source).

Oops. I meant if someone only has a ProLogic decoder then a 5 channel
digital signal will make no difference - it'll just use the 2 stereo
channels anyway for its source, and ProLogic decode them into the 4
channels (Left, Right, Centre, Rear).

[Michael]

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112929865.771106.40110@g14g2000cwa.googlegro ups.com...
>I wasn't aware that the signal encoding and the decoding method had
> separate names.
> I'll assume Anthony is correct here. So you and he are saying that the
> stereo signal is encoded with Dolby Surround, and decoded by Dolby
> ProLogic (or other related system).

Uh huh.

> That's fine. And this is quite separate from Dolby Digital 5.1 Channel
> Surround (what's its official name?)

Dolby Digital, or AC-3. As you say it can be anything from 1 to 5.1
channels.

[Anthony Horan]

On 7 Apr 2005 16:56:00 -0700, Greg Alexander wrote:

> Secondly Dolby has 2 technologies that are relevant to this discussion
> - Dolby Digital (surround) and Dolby ProLogic (surround). Most shows
> have dolby prologic built into their stereo signal now.

"Prologic" uses exactly the same encoding method as Dolby Surround. The
ONLY difference is in how that surround-encoded signal is Decoded.

> Basically if a show is broadcast in stereo and you have a ProLogic
> amplifier you'll get ProLogic surround.

You'll get DOLBY Surround, decoded using their ProLogic decoder. The
decoder should, of course, not be turned on during non-surround-encoded
programming, which is why the surround flag is useful.


- Anthony

[Greg Alexander]

Anthony Horan wrote:
> On 7 Apr 2005 16:56:00 -0700, Greg Alexander wrote:
>
> > Secondly Dolby has 2 technologies that are relevant to this
discussion
> > - Dolby Digital (surround) and Dolby ProLogic (surround). Most
shows
> > have dolby prologic built into their stereo signal now.
>
> "Prologic" uses exactly the same encoding method as Dolby Surround.
The
> ONLY difference is in how that surround-encoded signal is Decoded.

Dolby Digital is different to Dolby ProLogic.

[whoot-at-me]

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112918160.582229.8820@l41g2000cwc.googlegrou ps.com...
>
> wh00t-at-me wrote:
>> "Anthony Horan" <anthonyhoran@hotmail.com> wrote:
>> > jason887 wrote:
>> >
>> >> Does anyone know why only ABC, Nine & Ten standard
>> >> definition are the only channels to have dolby prologic?,
>> >> Seven, ABC2 & SBS only offer stereo, however ABC2 is
>> >> probably restricted by bandwidth.
>> >
>> > Ah, the common misconception strikes again :-)
>>
>> Why is it a misconception?
>> The viewer uses Pro Logic so the use of "Pro Logic" is
>> correct as far as they're concerned.
>
> I can see why _I_ think it's a misconception.
>
> Firstly, so what if the viewer is correct as far as they're concerned?
> If they're not speaking the same language as others then there's some
> miscommunication bound to happen.

As I said, even Dolby interchanges the use of Surround and Pro Logic so
there should be no misconception. In fact, using "Pro Logic" or "Pro Logic
II" is probably "more correct" becuase it identifies the decoding system
being used with Dolby Surround. That's essential for any fault finding.

[whoot-at-me]

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112929865.771106.40110@g14g2000cwa.googlegro ups.com...
>I wasn't aware that the signal encoding and the decoding method had
> separate names.
> I'll assume Anthony is correct here. So you and he are saying that the
> stereo signal is encoded with Dolby Surround, and decoded by Dolby
> ProLogic (or other related system).
>
> That's fine. And this is quite separate from Dolby Digital 5.1 Channel
> Surround (what's its official name?)

You can never beat the word of the experts. Have a look at
http://dolby.custhelp.com/cgi-bin/dolby.cfg/php/enduser/std_alp.php
That should help you with quite a few of your questions.

[Greg Alexander]

Mate, I have no idea why you keep answering the only part I have made
no comment on.

I'm comparing Dolby Digital with the analog versions. I've said already
I hadn't realised a difference and relationship between definitions
"Surround" and "Pro Logic" - but that STILL stands quite distinct from
Digital.

There is a misconception between the analog (ProLogic) and digital -
and your replies seem to be a good reflection of that.

[Greg Alexander]

They confirm my understanding. And there's no specific name for Dolby
Digital 5.1 channel - it falls under "Dolby Digital".

Note the misconception referred to was that ProLogic wasn't on SDTV. It
was an error to call it ProLogic when it should have been "Dolby
Surround" (an error I don't think matters much), but it was a
misconception between Dolby Digital and Dolby Surround.

>From the site:
Dolby Surround
The original Dolby multichannel film sound format that revolutionized
movie soundtracks. This technology encodes four channels of audio
(Left/Center/Right/Surround) onto just two audio tracks for media such
as TV broadcasts and feature films on VHS. Material encoded in Dolby
Surround is fully compatible for playback on mono and stereo systems:
upon playback on systems containing Dolby Pro Logic® technology, the
audio is reconstructed to its original four-channel surround sound.
Found in: Videocassettes; DVDs; Broadcast programming, film

Dolby Digital (AC-3)
Surround sound technology that delivers high-quality digital audio for
up to 5.1 discrete channels (Left/Center/Right/Left surround/Right
surround/Low-Frequency Effects).

(note "up to")
Also see:
http://www.dolby.com/professional/pro_audio_engineering/technologies.html

[whoot-at-me]

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112965652.960761.87900@f14g2000cwb.googlegro ups.com...
> Mate, I have no idea why you keep answering the only part I have made
> no comment on.

Actually I replied to *exactly* what you did comment on.

[Greg Alexander]

This misunderstanding I didn't get.. I just reread the post to find if
I missed something.

Jason had a question which seems to have 3 issues
- Why are some channels just stereo
- Why are some channels able to be decoded in ProLogic
- Why can't they all use Dolby Digital 5.1

I notice now that you and Anthony are only addressing the use of the
word ProLogic. My mistake. Anthony mentioned the misconception so that
too is correct in so far as he meant ProLogic terminology. I learned
the correct definition of Dolby Surround, thanks for info plus link.

My confusion stems from I was focussed on Jason's question, not just
the use of 'proLogic'. My apologies.

I also believe, perhaps wrongly, that when Jason says that some
channels do NOT broadcast Dolby Surround which ProLogic can decode,
that that's wrong.... would anyone care to comment on that? If it's
right, what's the situation in Sydney?

Thanks,
Greg

[Michael]

All channels can, and do broadcast Dolby Surround encoded programs, but not
every program is encoded with it.

"Greg Alexander" <galexand@ozemail.com.au> wrote in message
news:1112998520.219055.299560@z14g2000cwz.googlegr oups.com...
> I also believe, perhaps wrongly, that when Jason says that some
> channels do NOT broadcast Dolby Surround which ProLogic can decode,
> that that's wrong.... would anyone care to comment on that? If it's
> right, what's the situation in Sydney?