Dolby Surround carried on Freeview?
Paul D.Smith
I know that although the specs allow it, Freeview doesn't carry 5.1 sound,
but do you know if the 2 channels use Dolby or similar to provide at least
surround sound?
Paul SS
Mark Carver
You need an mp2 bit rate of not lower than 256k, for the Dolby Pro-Logic
signal not to be mangled out of existence.
IIRC only BBC 1, 2, 3 and 4 have their audio tracks on DTT at
that level ? ITV, 4 and 5 use 192k, and the other junk probably even less.
--
Mark
Please replace invalid and invalid with gmx and net to reply.
davidr...@postmaster.co.uk
> Paul D.Smith wrote:
> > All,
>
> > I know that although the specs allow it, Freeview doesn't carry 5.1
> > sound, but do you know if the 2 channels use Dolby or similar to provide
> > at least surround sound?
>
> You need an mp2 bit rate of not lower than 256k, for the Dolby Pro-Logic
> signal not to be mangled out of existence.
>
> IIRC only BBC 1, 2, 3 and 4 have their audio tracks on DTT at
> that level ? ITV, 4 and 5 use 192k, and the other junk probably even less.
That's why the BBC used 256kbps - and more importantly, people pump TV
through surround sound decoders even when the programme is nominally
stereo - and with early mp2 encoders, you got some horrible junk
through the surround channels at lower bitrates, whether the content
was officially "Dolby Surround" or not.
I bet 192k works OK now. I don't know. I don't listen to it!
Cheers,
David.
David
"Paul D.Smith" <paul_d...@hotmail.com> wrote in message
news:hbps6d$jl$1...@news.eternal-september.org...
I consulted with Dolby Labs. some time back as to the surround information
still being in the transmissions of Dolby movie films on TV.
The answer was if still in stereo and not been through any mono steps on the
way the encoded surround info. would still be there for my Dolby decoder to
use.
Sometimes TV companies buy ex-airline versions and sound will then be mono,
this is to get the film at a cheaper price.
One as to remember with surround sound it as got to be on the movie in the
first place in the cinema, not all producers put sound on the surround
system or it is not always noticeable. I do find people in home cinema
systems tend to have surround at higher levels than in the cinema.
--
Regards,
David
FREESAT HD as it is now it is a joke.
jamie powell
"Mark Carver" <mark....@invalid.invalid> wrote in message
news:7kbanmF...@mid.individual.net...
> Paul D.Smith wrote:
>> All,
>>
>> I know that although the specs allow it, Freeview doesn't carry 5.1 sound,
>> but do you know if the 2 channels use Dolby or similar to provide at least
>> surround sound?
>
> You need an mp2 bit rate of not lower than 256k, for the Dolby Pro-Logic
> signal not to be mangled out of existence.
>
> IIRC only BBC 1, 2, 3 and 4 have their audio tracks on DTT at
> that level ? ITV, 4 and 5 use 192k, and the other junk probably even less.
Although the official position has long been that 256k MP2 is "100% compatible
with Dolby Surround", in practice this never seemed to be the case with my Pro
Logic system.
On analogue satellite and pre-recorded VHS, the rear channel "came alive" -
one had the sensation of a real surround experience. On DVB, it was always
dull and quiet, to the point where you'd seldom even notice if the rear
speakers were switched off.
Andy Burns
I quite often notice that a musical backtrack gets steered to the rear
speakers.
Alan
Burns <usenet....@adslpipe.co.uk> wrote
>
>I quite often notice that a musical backtrack gets steered to the rear
>speakers.
The advertisers seem to make the most of a limited bit rate and surround
sound.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk
Brian Gaff
channels, notably five and at least one of the so called music channels,
there is often a decidedly pronounced swizzling sound as one might have
heard on an old knackered cassette tape as the azimuth varies, and more
recently on crap real player streams on the internet. I guess we are
probably hearing the adio effects of limited audio bandwidth due to low
sample rates then. The swizzling is presumably due to the system attempting
to cope with wide band frequencies and failing miserably..
Brian
--
Brian Gaff - bri...@blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Mark Carver" <mark....@invalid.invalid> wrote in message
news:7kbanmF...@mid.individual.net...
davidr...@postmaster.co.uk
> I consulted with Dolby Labs. some time back as to the surround information
> still being in the transmissions of Dolby movie films on TV.
> The answer was if still in stereo and not been through any mono steps on the
> way the encoded surround info. would still be there for my Dolby decoder to
> use.
That's not true. Intensity Stereo is still "stereo", but the phase
information is lost, so Dolby decoders have nothing to work with.
MPEG-1 layer II (mp2) uses intensity stereo at lower bitrates.
> Sometimes TV companies buy ex-airline versions and sound will then be mono,
> this is to get the film at a cheaper price.
I find this hard to believe (though I suppose it depends how far you
stretch the definition of "some TV companies" - there are some
transmission on satellite that appear to originate from one man and
his dog!). Airline versions are almost always 4x3, often stereo, and
sometimes include an occasional DOG of the airline name.
> One as to remember with surround sound it as got to be on the movie in the
> first place in the cinema, not all producers put sound on the surround
> system or it is not always noticeable. I do find people in home cinema
> systems tend to have surround at higher levels than in the cinema.
...and sometimes sit far too close to the rear speaker. This is why
the encoding artefacts steered to the rear channels sound so
objectionable, and why the BBC chose 256kbps.
You don't have to mix the sound track intentionally for surround to
end up with useful content on the "surround" channel - various
standard stereo microphone techniques will yield plenty of out-of-
phase information, which a Dolby decoder will send/steer to the rear
channels.
Cheers,
David.
davidr...@postmaster.co.uk
> Although the official position has long been that 256k MP2 is "100% compatible
> with Dolby Surround", in practice this never seemed to be the case with my Pro
> Logic system.
> On analogue satellite and pre-recorded VHS, the rear channel "came alive" -
> one had the sensation of a real surround experience. On DVB, it was always
> dull and quiet, to the point where you'd seldom even notice if the rear
> speakers were switched off.
No reason why that should be the case. If it's working _badly_, you'll
get more spurious crap coming out of your rear speakers, not less.
It's lower bitrate intensity stereo mp2 that's going to stop things
getting to your rear speakers - maybe you've heard a misconfigured mp2
encoder? I know someone in the BBC has messed up several times when
picking stereo mode on DAB, but DSat is fine.
If it's working well, then it's fine - you hear pretty much what
you're "supposed" to hear - especially with Dolby Pro-Logic (i.e.
steered) decoding.
Maybe there was actually more spurious crap on analogue satellite
(never had that), and pre-recorded VHS - making your rear speakers
"come alive" in ways that they shouldn't have?
Cheers,
David.
Dickie mint
> I quite often notice that a musical backtrack gets steered to the rear
> speakers.
I wish it did on mine, then I could turn it down when it got irritating..
:-)
Richard
Alan
<bri...@blueyonder.co.uk> wrote
>You may have inadvertently answered a question I have here. On some
>channels, notably five and at least one of the so called music channels,
>there is often a decidedly pronounced swizzling sound as one might have
>heard on an old knackered cassette tape as the azimuth varies, and more
>recently on crap real player streams on the internet. I guess we are
>probably hearing the adio effects of limited audio bandwidth due to low
>sample rates then. The swizzling is presumably due to the system attempting
>to cope with wide band frequencies and failing miserably..
I believe you are correct and it also happens on ITV1 quite a lot. My AV
will default to Dolby II (3.1) and I notice the same effects which can
be cured by forcing my AV to mono, and sometimes stereo.
If you want a really bad audio experience try the X Factor! In addition
to all of the technical problems they have you will get the rear
channels dedicated to the audience cheering at the same time as the
front channels deliver some tuneless warbling effect which I believe
they call singing. Why use one note when you've got another dozen you
can try?
Jim Lesurf
<eddec448-434a-46fc...@u13g2000vbb.googlegroups.com>,
I've encountered one or two commercial DVD Videos of old films where the
orginal sound would have been mono, but are (nominally) 'stereo' on the DVD
- however the two channels are quite clearly in antiphase! The effect can
be quite annoying when using a good stereo system.
Makes me wonder what they'd sound like when an analogue 'surround decoder'
was being used. I assume the sound would seem to all come from behind the
listener, but I don't use any surround setups so can only surmise that.
Slainte,
Jim
--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html
Dave Plowman (News)
Alan <ju...@admac.myzen.co.uk> wrote:
> If you want a really bad audio experience try the X Factor! In addition
> to all of the technical problems they have you will get the rear
> channels dedicated to the audience cheering at the same time as the
> front channels deliver some tuneless warbling effect which I believe
> they call singing. Why use one note when you've got another dozen you
> can try?
Can I ask why you watch it? Are you in a prison cell and your large cell
mate insists?
--
*The early bird gets the worm, but the second mouse gets the cheese *
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
jamie powell
<davidr...@postmaster.co.uk> wrote in message
news:bf87bb54-42b5-4a0b...@m13g2000vbf.googlegroups.com...
> On 22 Oct, 18:38, "jamie powell" <jamie_...@excite.com> wrote:
>
>> Although the official position has long been that 256k MP2 is "100%
>> compatible
>> with Dolby Surround", in practice this never seemed to be the case with my
>> Pro
>> Logic system.
>> On analogue satellite and pre-recorded VHS, the rear channel "came alive" -
>> one had the sensation of a real surround experience. On DVB, it was always
>> dull and quiet, to the point where you'd seldom even notice if the rear
>> speakers were switched off.
>
> No reason why that should be the case.
As if you'd know.
> If it's working _badly_, you'll get more spurious crap coming out of your
> rear
> speakers, not less.
I was talking about content (or lack thereof), not spurious crap.
> It's lower bitrate intensity stereo mp2 that's going to stop things
> getting to your rear speakers - maybe you've heard a misconfigured mp2
> encoder? I know someone in the BBC has messed up several times when
> picking stereo mode on DAB, but DSat is fine.
>
> If it's working well, then it's fine - you hear pretty much what
> you're "supposed" to hear - especially with Dolby Pro-Logic (i.e.
> steered) decoding.
>
> Maybe there was actually more spurious crap on analogue satellite
> (never had that), and pre-recorded VHS - making your rear speakers
> "come alive" in ways that they shouldn't have?
You are without clue, basically.
Graham.
"Jim Lesurf" <no...@audiomisc.co.uk> wrote in message news:50aeafc...@audiomisc.co.uk...
> In article
> <eddec448-434a-46fc...@u13g2000vbb.googlegroups.com>,
> davidr...@postmaster.co.uk <davidr...@postmaster.co.uk> wrote:
>> On 22 Oct, 18:01, "David" <david.p...@tesco.net> wrote:
>
>
>> You don't have to mix the sound track intentionally for surround to end
>> up with useful content on the "surround" channel - various standard
>> stereo microphone techniques will yield plenty of out-of- phase
>> information, which a Dolby decoder will send/steer to the rear channels.
>
> I've encountered one or two commercial DVD Videos of old films where the
> orginal sound would have been mono, but are (nominally) 'stereo' on the DVD
> - however the two channels are quite clearly in antiphase! The effect can
> be quite annoying when using a good stereo system.
And if you paralleled the left and right channels to feed a mono distribution
system, you would end up with SFA.
--
Graham.
%Profound_observation%
Jim Lesurf
<m...@privacy.net> wrote:
> "Jim Lesurf" <no...@audiomisc.co.uk> wrote in message
> news:50aeafc...@audiomisc.co.uk...
> >
> > I've encountered one or two commercial DVD Videos of old films where
> > the orginal sound would have been mono, but are (nominally) 'stereo'
> > on the DVD - however the two channels are quite clearly in antiphase!
> > The effect can be quite annoying when using a good stereo system.
> And if you paralleled the left and right channels to feed a mono
> distribution system, you would end up with SFA.
Indeed. If I press the 'mono' button on the Quad 34 I use with the balance
set centrally then the sound also vanishes for these discs.
Fortunately, with the 34, the balance control is 'before' the mono link, so
I can move the balance fully to one side and just use one input channel for
both outputs as mono. That suppresses the problem. But these discs must be
a PITA for some users using good stereo setups with no similar control
ability. I guess this is a sign that the people making the discs didn't
bother to check what they'd done with the sound.
davidr...@postmaster.co.uk
> <davidrobin...@postmaster.co.uk> wrote in message
Note to self: even when Jamie doesn't appear to be trolling, he's
still but one post away from doing so.
jamie powell
<davidr...@postmaster.co.uk> wrote in message
news:b01cc344-ffa8-446f...@g31g2000vbr.googlegroups.com...
> On 23 Oct, 22:26, "jamie powell" <jamie_...@excite.com> wrote:
>> <davidrobin...@postmaster.co.uk> wrote in message
>>
>
> Note to self: even when Jamie doesn't appear to be trolling, he's
> still but one post away from doing so.
Rather a troll than a charlatan.
Mike Thomas
> Note to self: even when Jamie doesn't appear to be trolling, he's
> still but one post away from doing so.
Well, heck, you don't suppose that's related to the fact that Jamie has
always been a nasty piece of work? Killfile's thataway.