Why hasn't the LT-RT been put to death yet?

[Eric L]

To clarify, I am not talking about a Dolby DMU encoded LT-RT for theatrical playback.

I am talking about the LT-RT that is on every single projects video delivery requirement list that I read.

Clients don't want to pay for an LT-RT mix. They don't even want to pay for the time to just listen to an LT-RT fold down of the 5.1 mix.

QC does not listen to the LT-RT decoded in a calibrated surround environment. Most clients don't listen to LT-RT decoded either. Most people (including QC) hear the LT-RT as Stereo. Yet it is not a stereo mix.

So if clients were willing to pay for a separate mix for the LT-RT, would you listen to it decoded to LCRS or Stereo. You only get to pick one, because there is no way a client is paying for three mixes. In fact this point is moot, because they are not going to pay for a separate mix anyway.

Some broadcasters are broadcasting 5.1 mixes and letting the set top box do a Lo-Ro fold down for listeners without a 5.1 system. They do not even send out the LT-RT.

Other broadcasters are sending out Stereo Mixes in a 5.1 container. I see the AC3 bitstream, but I only hear two channels.

All DME delivery specs I have ever seen, are for Stereo, not LT-RT. So if you make Lo-Ro DME stems, and some one down the line mixes these to reconstitute a mix, it is not an LT-RT mix. (I know from first hand experience from my time at a huge international versioning facility that this happens all the time.)

Of course if a proper LT-RT mix was paid for, then making LT-RT DME stems is not a problem. But again, that is not going to happen.

It just seems so impractical to spend the time to make all these deliverable elements, when the mixer was making decisions based on a 5.1 mix. Especially when, I would bet, a majority of listeners do not even get a true encoded LT-RT of a mix to their listening device. It's either the 5.1 or a Lo-Ro fold down of the 5.1. If they do get a true encoded LT-RT to their playback system, I would again bet, that a majority are listening to it un-decoded through two speakers. TV speakers or computer speakers.

So, I am officially calling for the end of the LT-RT deliverable. In my opinion the cost-benefit ratio is heavy on the cost side.

It is time to let those listeners, who are unwilling to install a 5.1 system, settle for a plain old stereo mix. There can't be that many people with a Dolby Prologic LCRS system left in the world. And those people probably have the surround speakers upfront next to the front speakers like my sister does. My own sister! Ugh.

[iluvcapra]

Originally Posted by Eric L

So, I am officially calling for the end of the LT-RT deliverable. In my opinion the cost-benefit ratio is heavy on the cost side.

It sounds like you're not calling for the end of the Lt-Rt deliverable as much as you're calling for the end of the 2 track deliverable, tout court.

[georgia]

Good luck with that...

[Eric L]

Originally Posted by iluvcapra

It sounds like you're not calling for the end of the Lt-Rt deliverable as much as you're calling for the end of the 2 track deliverable, tout court.

Well if my rant read that way, it was not intended. There is obviously a need for two track audio deliverables. Television sets.

My objection is to the "encoded" or "matrixed" two track deliverable. It does not offer anything that the 5.1 can't do better, yet it takes much more time to generate these elements, for what benefit to the end user?

Another point I did not mention, is most true stereo mixes played through LT-RT decoder circuit will have a certain amount of surround info generated and mono dialogue will default to center.

See, free surround sound.

Thanks for reading.

[BIGBANGBUZZ]

I think it's a waist..
I think for TV it should be Lo Ro and 5.1.

90% of the public will listen to it in stereo unfortunately.

[nathand]

Most "up-to-date" Network Broadcast Deliverable Sheets give the option of delivering an LT-RT or Lo-Ro.

I've opted for the Lo-Ro for a long while now.

[iluvcapra]

Originally Posted by Eric L

Well if my rant read that way, it was not intended. There is obviously a need for two track audio deliverables. Television sets.

My objection is to the "encoded" or "matrixed" two track deliverable. It does not offer anything that the 5.1 can't do better, yet it takes much more time to generate these elements, for what benefit to the end user?

Another point I did not mention, is most true stereo mixes played through LT-RT decoder circuit will have a certain amount of surround info generated and mono dialogue will default to center.

See, free surround sound.

Thanks for reading.

You see, everything you say that's bad about the Lt-Rt-- it's never monitored, it isn't often broadcast, they don't want to pay for the pass, etc.-- is just as true of a Lo-Ro as of an Lt-Rt.

[philper]

I see your point re commercial TV I guess, but most of my clients have festival ambitions and arthouse theatrical dreams, and the LtRt works very well for them in those situations. It's been awhile since I asked anyone at a commercial (ie non-PBS) network what they used the LtRt for (if anything), it might just be another track-filler "because we can" sort of thing. But if the "real" important deliverable is a 5.1 mix then, anymore, I think I agree that the LtRt is superfluous.

phil p

[Eric L]

Originally Posted by iluvcapra

You see, everything you say that's bad about the Lt-Rt-- it's never monitored, it isn't often broadcast, they don't want to pay for the pass, etc.-- is just as true of a Lo-Ro as of an Lt-Rt.

I don't agree that it is "just as true". But I do see your point regarding the home listener never needing a two track mix. Unfortunately, clients still want a two track for their editing environment. Even though only them and QC will ever hear it.

LoRo does not need an encoder circuit. Hardware or software.

LoRo does not need to be monitored decoded to check for steering issues.

This allows for simpler bussing in mix sessions using less tracks/voices.

LoRo will usually not sound phasey or washy when surrounds are folded in.

LoRo can be reconstituted by the stereo DME. Making an LT/RT DME is a pain.

[Eric L]

Originally Posted by nathand

Most "up-to-date" Network Broadcast Deliverable Sheets give the option of delivering an LT-RT or Lo-Ro.

I've opted for the Lo-Ro for a long while now.

I think we are going to start doing the same. The clients will get a LoRo fold down from the 5.1. It will be explained that this is an unmonitored version.

A LT/RT mix will be made available to them at an added cost if they desire such a deliverable. I'm so tired of getting complaints about the fold down of the mix sounding "different" in their edit room.

Phil, festival mixes and theatrical mixes are indeed a different story. Often, we mix those LCRS just as they will be presented.

[nucelar]

LtRt has the "dolby aura", which clients like, it somehow must be better. Also the term "total" versus "only" makes it more attractive. I'm not joking. At least here many clients have no clue of audio technology, let alone distinguish an LtRt from a LoRo and its implications. Recently we were requested a "dolby 2.0" as a deliverable, having only a stereo M&E. After asking, we finally did a regular stereo mix and everything was fine.
I agree LtRt should be phased out for broadcast.

[cananball]

Seems to me set top boxes create LtRt's automatically from the 5.1 fold down based on its metadata. Things are changing I'm not sure whats being broadcast. Where I live they (used to not sure about now) only include 5.1 on HD channels. There is an SD version and an HD version of each channel. The SD version was either stereo or LtRt not sure which. Would love to know if it was LtRt from deliverable or 5.1 folddown on network side. Since then my cable provider has introduced hybrid channels either SD or HD depending what your TV was capable of.

[Henchman]

It's for countries where broadcasters are still broadcasting in stereo, and even from 3/4"
And for online streaming in low bandwidth situations.

[mikevarela]

great read... had wondered myself. Being that the home box folds down anyhow, why the extra work?

on this note, anyone out there try the included PT10 folddown plugin yet? LoRo one

[Eric L]

Originally Posted by cananball

Seems to me set top boxes create LtRt's automatically from the 5.1 fold down based on its metadata.

Actually it is a Lo-Ro that is created. No matrix encoding in the set top box. But your Pro Logic receiver may still spread the sound to a faux LCRS.

Other countries can broadcast LoRo if they are not up to the latest digital broadcast standards yet. LT-RT is not worth the effort in my opinion.

[Tom Fleischman]

LtRt was never intended to be used as a release format. It was designed as a way to get four channels of audio on a film print, period.

The concurrent entry into the media marketplace of Dolby Stereo theater formats and home delivery of movies on cable television in the mid 1970's led Dolby to market ProLogic circuits in consumer products which could decode an LtRt track to 4 channels on a home system. This worked fairly well given the impossibility of standardizing the home listening environment, but it was still a cost cutting measure. If broadcasters would use the LtRt track provided with the delivery package (as some do), things would be better, but they have taken the cost cutting a step further by relying on fold down algorithms built into set-top boxes to create a stereo (Lo-Ro) track, and this usually results in a mangled mix, particularly if that is the track that is routed to the Prologic decoder feeding a surround loudspeaker setup.

So...should LtRt be retired? Once film prints are retired, which will happen soon, yes. And then start paying us to do a proper fold down to stereo.

[Henchman]

Originally Posted by Tom Fleischman

And then start paying us to do a proper fold down to stereo.

Hahahahahahaha, whew.
Ending a serious post with a joke.
Hahahahahahaha.

Very nice.

[philper]

I'll stop making LtRts when I'm sure all festivals and small cinemas can and will properly play off of 5.1 versions of mix, however they arrive there. I don't see this happening soon.

phil p

[Tom Fleischman]

Originally Posted by philper

I'll stop making LtRts when I'm sure all festivals and small cinemas can and will properly play off of 5.1 versions of mix, however they arrive there. I don't see this happening soon.

phil p

It won't be long before all theaters are running DCP's. The studios won't stick with film a minute longer than they have to.

[Eric L]

Originally Posted by philper

I'll stop making LtRts when I'm sure all festivals and small cinemas can and will properly play off of 5.1 versions of mix, however they arrive there. I don't see this happening soon.

phil p

Festivals and small theatres that cannot playback 5.1 (usually due to financial reasons) tend to have other serious issues that can really mess up a sound mix.

Fried speaker components, swapped channels, polarity issues and bad acoustics are some of the problems I have witnessed. In my opinion, a stereo mix is a safer choice for these venues. Most people understand two speaker systems.

[Eric L]

Originally Posted by Tom Fleischman

It won't be long before all theaters are running DCP's. The studios won't stick with film a minute longer than they have to.

Looking forward to that day.

[philper]

Originally Posted by Eric L

Festivals and small theatres that cannot playback 5.1 (usually due to financial reasons) tend to have other serious issues that can really mess up a sound mix.

Fried speaker components, swapped channels, polarity issues and bad acoustics are some of the problems I have witnessed. In my opinion, a stereo mix is a safer choice for these venues. Most people understand two speaker systems.

We have found the opposite, and feel that LtRt is the safe choice for now for those venues, an opinion we arrived at the hard way. Since we started doing them we have had no issues with steering problems caused by LoRos being sent through a Dolby decoder (because the venue either didn't want to or didn't know how to change settings), and the film can even play in mono ok if it has to. If they DO have a good setup they also probably don't have a way to play 5.1 discrete channels, just 2 off a video deck. I pray for the festivals to get more with it in terms of how they play my clients' films, but they are under a lot of economic pressure to keep things very simple. If they eliminated the Dolby decoders from the setups used for these shows (often temporary) then I'd be fine with sending LoRo. But until I'm convinced that they have they get LtRt. The other problems with festival playback are beyond my control (ie bad systems), but I can make sure we are compatible with however they play the film (currently). These same clients usually use the LtRt for their DVD versions as well, and are pleased that they can have surround when the disk is played on a home theatre system and stereo (or mono) playback on lesser systems from the same track of the same disk.

phil p

[cananball]

Originally Posted by Eric L

Actually it is a Lo-Ro that is created. No matrix encoding in the set top box. But your Pro Logic receiver may still spread the sound to a faux LCRS.

Other countries can broadcast LoRo if they are not up to the latest digital broadcast standards yet. LT-RT is not worth the effort in my opinion.

I swear i saw a software encoder where in the metadata options you could choose LoRo or LtRt downmix. This was a long time ago and I don't do Dolby Digital encoding, Can anyone confirm this?

[rfnoise]

It has been a standard option on Dolby Digital decoders for a long time for manufacturers that choose to impliment it. My old DVD player will downmix to LoRo or LtRt. I would think a set top box could as well unless the box's manufacturer just didn't bother.

When encoding Dolby Digital many encoders allow you to select whether the surround channel(s) phase is twisted 90 degrees. It is for the same purpose I believe, but does it at the encode stage, not decode stage. Maybe that's what you recall seeing?

[charles maynes]

Hey Eric-

I think thats a great question and I think there is no clear answer.... my first suggestion would be to essentially roll the cost into the mix budget, and allow it the time required for verification- In the end, even if it gets done without monitoring, WE are responsible for its integrity, whether it gets used or not. So, if does get bullocks'd, we are always required to fix it. Which brings us to the classic Hollywood axiom- "There is never enough money to do it right, but there is always enough money to do it again".