[chrisjr]

Quote:

Originally Posted by Deacon1972

They don't mean that at all.....

Exactly. As I try to explain over and over again. I'm not sure if spinney2 really does find it hard to understand what I have written, I've not made myself sufficiently clear or he is just trolling for the hell of it.

Quote:

Originally Posted by Deacon1972

How can you decode surround sound information on a stereo soundtrack when that information has not been encoded on to the stereo soundtrack in the first place, unless you are saying there are no exceptions and Dolby surround is present on all stereo soundtracks.

Well he has posted on more than one occasion that 2.0 is surround without qualifying it by saying 'if Dolby encoded" or similar. So who knows?

Quote:

Originally Posted by Deacon1972

You do realise a DPL decoder can decode and create soundtracks. It will decode Dolby surround information when encoded or present on a stereo soundtrack, it will also convert plain stereo to 5.1 by using digital processing (broadband logic steering), basically its fake, not that different to the jazz, pop, disco, church DSP's you find on some av receivers.

That is something people who don't understand the core technology have difficulty getting their heads round. Just because some noise comes out of the rear speakers it does not mean that the sound track they are listening to is actually surround sound to begin with.

Bit like thinking that Dave on Freeview is HD just because the letters H and D were printed alongside each other on the box your telly came in.

[spiney2]

Quote:

Originally Posted by chrisjr

How many more times does it need explaining?

A two channel sound track will only contain surround sound information if deliberately encoded from a discrete multi channel master mix in such away as to allow a complimentary decoder to separate out the original channels. This process is not lossless as the decoded channels will not be 100% identical to the original source channels. So in that sense precise positional information has been lost to a certain extent. But they will be pretty close, close enough to give a good enough surround effect for most situations. So it is lossy but it is (imperfectly) reversible.

If the two channel sound track is not encoded from a multi channel master mix, or any such master is not encoded specifically but the channels are simply summed together, then any surround information it contains is entirely accidental and it is anyone's guess what a decoder will do with it. So that scenario is both lossy and irreversible. In that the original surround mix has been lost and cannot be reversed back to any sort of facsimile of the original.

i fully agree that, you cant get something from nothing, and down mixing gives a lossy lower fi version of this from which the original cannot be recovered. No quibble on these points. But even dolby call their 2.0 matrix "surround" .....

[spiney2]

..... for about 20 years, ignoring 70mm film, 2.0 was the only version that existed ......

[anthony david]

[quote=chrisjr;77000044]
That is something people who don't understand the core technology have difficulty getting their heads round. Just because some noise comes out of the rear speakers it does not mean that the sound track they are listening to is actually surround sound to begin with.

True but it may be, ITV dubbing suites did have Dolby 2ch surround encoders although how much they are used these days I'm not sure as I am now retired and the station has relocated to Salford. Dolby Surround isn't mentioned in the credits because they wanted to charge us for using their logo.

[spiney2]

i agree that, if no surround sound was deliberately matrixed in, so there is only some residual antiphase, then that is deliberately stretched out so the 2 residual rear channels meet at the back, it is quite fair to call this fake.

[spiney2]

itv does tx films in surround. Since obviously, if on the original soundgrack, then there is no way of removing it! Somtimes clearly analogue 2.0 since pitch variation is fairly obvious, sometimes quite bad ......

[spiney2]

..... Although some of the james bond ..... including roger moore ones with surround sound ..... have been shown in mono, for whatever reason ......

[anthony david]

Quote:

Originally Posted by spiney2

itv does tx films in surround. Since obviously, if on the original soundgrack, then there is no way of removing it! Somtimes clearly analogue 2.0 since pitch variation is fairly obvious, sometimes quite bad ......

There should never be any pitch variation on a telecine transfer, unless you are referring to the fact that the film is run at 25fps giving a pitch increase of around 4%. Some transfer suites use a pitch shifter which could give some odd effects at times perhaps. Very old films can suffer shrinkage and printing/sound marrying problems but it's rare.

A limited number of older films had 4track magnetic sound, these prints were sometimes produced for Broadway/London West end presentations and the surround effects were often quite limited. Most prints would have been mono, few telecine machines are fitted with "penthouse mag heads" so unless a distributor has made a surround copy for DVD release etc, and is prepared to let TV have it at a reasonable price then mono is all you are going to get.

[mossy2103]

Quote:

Originally Posted by spiney2

itv does tx films in surround. Since obviously, if on the original soundgrack, then there is no way of removing it! Somtimes clearly analogue 2.0 since pitch variation is fairly obvious, sometimes quite bad ......

Of course they sometimes transmit surround if encoded, but only Dolby Surround-encoded material, not 5.1 material.

[anthony david]

Quote:

Originally Posted by mossy2103

Of course they sometimes transmit surround if encoded, but only Dolby Surround-encoded material, not 5.1 material.

Exactly, the two tracks are sent via a Dolby noise reduction unit (switched to A or SR) built into the telecine's audio rack and they then go out via a manual gain control to line just like everything else. Dolby Surround has an advantage in that it can give a pleasant ambient effect for normal stereo viewers. It is sometimes used on dramas for the same reason. Some films have a dynamic range that is too wide for most TVs and steps have to be taken to reduce it otherwise there would be complaints.

[spiney2]

Quote:

Originally Posted by anthony david

There should never be any pitch variation on a telecine transfer, unless you are referring to the fact that the film is run at 25fps giving a pitch increase of around 4%. Some transfer suites use a pitch shifter which could give some odd effects at times perhaps. Very old films can suffer shrinkage and printing/sound marrying problems but it's rare.

A limited number of older films had 4track magnetic sound, these prints were sometimes produced for Broadway/London West end presentations and the surround effects were often quite limited. Most prints would have been mono, few telecine machines are fitted with "penthouse mag heads" so unless a distributor has made a surround copy for DVD release etc, and is prepared to let TV have it at a reasonable price then mono is all you are going to get.

i am referring to really bad pitch wow especially obvious on sustained long notes in music, so obviously its an analogue soundtrack....

[spiney2]

Quote:

Originally Posted by mossy2103

Of course they sometimes transmit surround if encoded, but only Dolby Surround-encoded material, not 5.1 material.

if 5.1 is present then this is auto downmixed in the dolby decoder. Even if the analogue soundtrack were transmitted in parallel, it wd still be dolby matrix encoded .....

[spiney2]

Quote:

Originally Posted by anthony david

Exactly, the two tracks are sent via a Dolby noise reduction unit (switched to A or SR) built into the telecine's audio rack and they then go out via a manual gain control to line just like everything else. Dolby Surround has an advantage in that it can give a pleasant ambient effect for normal stereo viewers. It is sometimes used on dramas for the same reason. Some films have a dynamic range that is too wide for most TVs and steps have to be taken to reduce it otherwise there would be complaints.

all sorts of processing is used on all types of soundmix. Sometimes they get it badly wrong ..... a 2.0 source is range limited anyway of course ...... Sometimes they transmit widescreen as 4:3 to help.people who wear glasses ......

[spiney2]

anyway we now got 9.1, so obviously, 7.1 must be FAKE surround.....

[spiney2]

Quote:

Originally Posted by anthony david

There should never be any pitch variation on a telecine transfer, unless you are referring to the fact that the film is run at 25fps giving a pitch increase of around 4%. Some transfer suites use a pitch shifter which could give some odd effects at times perhaps. Very old films can suffer shrinkage and printing/sound marrying problems but it's rare.

A limited number of older films had 4track magnetic sound, these prints were sometimes produced for Broadway/London West end presentations and the surround effects were often quite limited. Most prints would have been mono, few telecine machines are fitted with "penthouse mag heads" so unless a distributor has made a surround copy for DVD release etc, and is prepared to let TV have it at a reasonable price then mono is all you are going to get.

dr no may have been mono. I dont think from russia with love was. at that point the bond franchise was already big .....

[spiney2]

Quote:

Originally Posted by anthony david

Exactly, the two tracks are sent via a Dolby noise reduction unit (switched to A or SR) built into the telecine's audio rack and they then go out via a manual gain control to line just like everything else. Dolby Surround has an advantage in that it can give a pleasant ambient effect for normal stereo viewers. It is sometimes used on dramas for the same reason. Some films have a dynamic range that is too wide for most TVs and steps have to be taken to reduce it otherwise there would be complaints.

sr is irrelevant since its just frequency banded noise gates for extra hiss reduction ...... all tv sound has noise gates anyway .....

[mossy2103]

Quote:

Originally Posted by spiney2

anyway we now got 9.1, so obviously, 7.1 must be FAKE surround.....

Eh?

The soundtrack is simply mixed/encoded for more speaker positions, in the case of 9.1 giving better sound positioning by using two front height channels

http://www.dolby.com/us/en/technolog...round-7-1.html

http://www.dolby.com/us/en/guide/sur...9-1-setup.html

[Deacon1972]

Quote:

Originally Posted by spiney2

anyway we now got 9.1, so obviously, 7.1 must be FAKE surround.....

DTS HD MA 7.1 is certainly not fake, all channels are discrete.

9.1 and 11.1 are not fully discrete formats, they are similar to Dolby Digital EX and DTS ES.

9.1 adds matrix channels to 7.1, either height or width - giving you L/C/R/FLW/FRW or FLH/FRH/LS/RS/SBL/SBR/SUB

11.1 adds matrix channels not used in 9.1. L/C/R/FLW/FRW/FLH/FRH/LS/RS/SBL/SBR/SUB

Dolby Atmos is discrete in a 7.1 setup ie. 7.1.2 or 7.1.4

Quote:

Originally Posted by spiney2

all sorts of processing is used on all types of soundmix. Sometimes they get it badly wrong ..... a 2.0 source is range limited anyway of course ......
Sometimes they transmit widescreen as 4:3 to help.people who wear glasses ......

Surely this is a joke?

[spiney2]

how it sounds depends not so much on whether discrete, but more on how the decoder works with various psychoacoustic effects, this being a big differerence tween the home and cinema versions ...... of course as ever more surround channels added this increases spatial accuracy ..... A pity most movie dialogue now is incoherent grunts ......

[spiney2]

Quote:

Originally Posted by mossy2103

Eh?

The soundtrack is simply mixed/encoded for more speaker positions, in the case of 9.1 giving better sound positioning by using two front height channels

http://www.dolby.com/us/en/technolog...round-7-1.html

http://www.dolby.com/us/en/guide/sur...9-1-setup.html

but 5.1 is just a higher res version of 2.0 ...... and the constant claim is that any lower res version is fake .......

[anthony david]

Quote:

Originally Posted by spiney2

sr is irrelevant since its just frequency banded noise gates for extra hiss reduction ...... all tv sound has noise gates anyway .....

Where do you get this rubbish from. A,B,C and SR are all encoded noise reduction systems not gates. TV sound does not routinely have noise gating either. As for pitch variations/wow, it was inaudible on the machines I maintained and I'm sure that newer machines are even better. Everything has to meet full broadcast spec.

According to Imdb, the first Bond film with stereo sound in general distribution was The Spy Who Loved Me in 1977. The success of Star Wars caused major cinema chains to start installing surround sound, before that only a few cinemas had 4 track mag even fewer 70mm 6 track mag so very little was released in that format. I do remember seeing an earlier Bond in 4 track at the ABC Oxford which sometimes got hold of a "west end" print. The Granada Bedford was also sometimes lucky to get one as well. These specials usually only had a limited number of surround effects in an otherwise mono film. Mag stripes didn't wear well so the sound on those copies may now be unplayable. The production companies may of course still have the stereo sepmag mix in their vaults should they wish to use it for DVD etc.

[chrisjr]

Quote:

Originally Posted by spiney2

but 5.1 is just a higher res version of 2.0 ...... and the constant claim is that any lower res version is fake .......

What on earth do you mean by high and low res?

And as for 2.0 being "fake". That only applies if the two channel sound track has not been specifically encoded from a multichannel surround master. Therefore it does not deliberately include any surround signals.

Any surround information that a ProLogic or similar decoder generates from an un-encoded two channel sound track is obviously unintentional. So in that respect could be described as fake in that the sound engineer making the original master mix did not intend it to be there.

But if you start out with a deliberately mixed for surround master and encode that mix down to two channels then any surround signals the decoder produces are intended to be there so cannot be described as fake. Albeit that the encode decode process is not completely perfect, still doesn't make it fake though.

[anthony david]

Quote:

Originally Posted by spiney2

all sorts of processing is used on all types of soundmix. Sometimes they get it badly wrong ..... a 2.0 source is range limited anyway of course ...... Sometimes they transmit widescreen as 4:3 to help.people who wear glasses ......

Oh I missed this hilarious one, I wear glasses, perhaps I should start a "bring back Academy Ratio" campaign.

There is a huge dynamic range on Dolby SR optical tracks, they have to match the digital tracks as far as possible in case a digital reading error causes the system to momentarily default to them.

[Deacon1972]

Quote:

Originally Posted by spiney2

but 5.1 is just a higher res version of 2.0 ...... and the constant claim is that any lower res version is fake .......

It's only fake if there is no surround information encoded.

A DLP decoder not only decodes, it can also expand the original stereo soundtrack by creating more channels.

DPLII takes stereo and creates 5.1

DPLIIX takes stereo to 5.1 and creates 7.1.

DPLIIZ takes stereo to 7.1 and creates 9.1

Same applies to DTS Neo:6 and DTS Neo:X, the decoders create channels from a lesser source.

The above formats bear no resemblance to DTS HD MA 7.1 or 9.1 with matrix height/width channels.

[spiney2]

Quote:

Originally Posted by anthony david

Oh I missed this hilarious one, I wear glasses, perhaps I should start a "bring back Academy Ratio" campaign.

There is a huge dynamic range on Dolby SR optical tracks, they have to match the digital tracks as far as possible in case a digital reading error causes the system to momentarily default to them.

big yes but dolby a cannot match digital for range ...... it is going to be much ess than "a" with analogue tape ......