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Dial norm QC fail? Mixers (Analog)
Old 4th September 2011
  #1
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jahtao's Avatar
Dial norm QC fail?

Hey.

So I've mixed this show for Sky. The loudness for the whole show measured with EBU R128 loudness is -24. So when making my Dolby E encodes I've set the metadata to dial norm to -24.

Sky tell me the tape had passed QC but when they measure the dial norm its coming in closer to -34..

I literally don't understand how this is possible unless they are QC-ing it wrong. Which I think is unlikely. This is the first time I've done this kind of work : /

What gives?!?!?!?!?

Pls help!
Matt
Old 4th September 2011
  #2
How are you measuring it? Dialog intelligence on or off?
Old 4th September 2011
  #3
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jahtao's Avatar
Unless I'm mistaken, dialogue inteligence is not relavent here. That's an LM100, LKFS type of deal. Spy spec calls for EBU R128 BS 1771 loudness
Old 4th September 2011
  #4
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So, if you play the content back through a Dolby-E decoder, does it appear to be 10 dB lower than you would normally expect?
Old 4th September 2011
  #5
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sky is wierd.

must be the only network that cares for correct metadata settings in the dolby e.
and i think they do so because if they reject it then that can say, how about we get the stems and we layback the dolby e to the correct settings for a low low price. or use our dolby dp600 to redo lkfs.

seriously, from the 2000+ laybacks ive been involved with sky was one of the 2 networks that ever have rejected for correct dialorn settings for dolby e.


and the EBU R128 BS 1771 loudness you are reffering to is all about LKFS and the -34 sounds like a dialog intelligence off thing.

EBU TECHNICAL - Event - Loudness Webinar - part 1

get the dolby media meter (or lm100) or anything else that give lots of money to dolby, that way they can pay for a "informative campaign" to clear up things for all this mess they got us into.
Old 4th September 2011
  #6
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Quote:
Originally Posted by tpad View Post
So, if you play the content back through a Dolby-E decoder, does it appear to be 10 dB lower than you would normally expect?
no.
Old 4th September 2011
  #7
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jahtao's Avatar
Quote:
Originally Posted by gsilbers View Post
sky is wierd.

must be the only network that cares for correct metadata settings in the dolby e.
and i think they do so because if they reject it then that can say, how about we get the stems and we layback the dolby e to the correct settings for a low low price. or use our dolby dp600 to redo lkfs.

seriously, from the 2000+ laybacks ive been involved with sky was one of the 2 networks that ever have rejected for correct dialorn settings for dolby e.


and the EBU R128 BS 1771 loudness you are reffering to is all about LKFS and the -34 sounds like a dialog intelligence off thing.

EBU TECHNICAL - Event - Loudness Webinar - part 1

get the dolby media meter (or lm100) or anything else that give lots of money to dolby, that way they can pay for a "informative campaign" to clear up things for all this mess they got us into.
As I understand it Spy don't measure loudness with the LM100. What are you saying?
Old 4th September 2011
  #8
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Quote:
Originally Posted by jahtao View Post
As I understand it Spy don't measure loudness with the LM100. What are you saying?
How do they measure it? With what? I think you get to ask this question since they failed your mix.... Were they playing your mix back so that your tone hit -20? Old-fashioned, I know, but that's where I'd start....

phil p
Old 4th September 2011
  #9
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gsilbers's Avatar
 

Quote:
Originally Posted by jahtao View Post
As I understand it Spy don't measure loudness with the LM100. What are you saying?
i do not know how or what they use to measure loudness but there are several instruments .

sky prolly uses something like this rasterizer for QC which can decode dolby e and also measure loudness:

Welcome to DS Video - VIDEOTEK VTM4100PKG Multiformat Modular On-Screen Monitor

the new updates for the harris has EBU and ATSC presets so dunno how exactly they are measuring but as someone said before, must be something with dialog intelligence.
just give it a try. download the demo for the dolby media meter and run your mix through it and see if u get similar readings.

maybe this will help.:

DialNorm 101, by Dave Moulton

last paragraph
Old 4th September 2011
  #10
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Could the fail be due to improperly set metadata? (So they are playing back too low?)

phil p
Old 5th September 2011
  #11
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Dialnorm is going to reduce the level to -31 dBFS at the output of the decoder. If the instrument Sky is using to measure level is making the measurement after Dolby-E decode instead of before, then they are going to be seeing -31, not -24. If you were to knock -31 down -3 dB in each channel due to equal power split, that would give you -34 dBFS. Just a wild guess.
Old 5th September 2011
  #12
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jahtao's Avatar
So they've checked it again are now saying it does decode at the right level. I've wasted a day chasing this, ughhh. But fair enough these things happen.

Speaking to them I've also learned that when they QC loudness they only measure the centre channel. This is not the way the EBU R128 algorhythm was intended to be used, and this is not stated on their spec.

Ughhhhh : (
Old 5th September 2011
  #13
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Quote:
Originally Posted by jahtao View Post
So they've checked it again are now saying it does decode at the right level. I've wasted a day chasing this, ughhh. But fair enough these things happen.

Speaking to them I've also learned that when they QC loudness they only measure the centre channel. This is not the way the EBU R128 algorhythm was intended to be used, and this is not stated on their spec.

Ughhhhh : (
Good. That was the simplest possible explanation (which is usually the right one). Kind of a diplomatic challenge in this case, though! Be glad they are measuring only the C--makes your life easier (I think).

phil p
Old 6th September 2011
  #14
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Quote:
Originally Posted by jahtao View Post
So they've checked it again are now saying it does decode at the right level. I've wasted a day chasing this, ughhh. But fair enough these things happen.

Speaking to them I've also learned that when they QC loudness they only measure the centre channel. This is not the way the EBU R128 algorhythm was intended to be used, and this is not stated on their spec.

Ughhhhh : (
Oh god, ive just mixed my first series for sky. Expecting the worst after hearing this! :/
Old 6th September 2011
  #15
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Quote:
Originally Posted by FullFrequency View Post
Oh god, ive just mixed my first series for sky. Expecting the worst after hearing this! :/
And on the surface they seem one of, if not the most, technically progressive broadcasters in our great country : /

How did u do your mixes?
Old 6th September 2011
  #16
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Quote:
Originally Posted by jahtao View Post
And on the surface they seem one of, if not the most, technically progressive broadcasters in our great country : /

How did u do your mixes?
I fed the meter as LCR seeing as the dial channels are spread like that on their spec. I aimed purposely for -25 as at -23 it was too hot for the automated LtRt downmix . Even then the stereo was permanently sitting on 6ppm. I think personally that there's something not quite right with their spec. A guy I work with told me that they pull the downmix down by 4db, so in the end I stopped worrying about that side of things. talk about fixing things after the event though! Why not set dialnorm at -27 +-2 and give a bit of headroom?!

I had 7hrs to mix 45mins worth of material per show...... unfortunately compression had to be used more than I'd have liked :(

I think though that their delivery requirement is way excessive. They should simplify and get it right.... beats me why they need 4 Dolby e streams and an LtRt when they're not even the international distributor.

Oh well! At least if they fail my mixes I have useful information that I can speak to them about.
Old 6th September 2011
  #17
Quote:
Originally Posted by FullFrequency View Post
I think though that their delivery requirement is way excessive. They should simplify and get it right.... beats me why they need 4 Dolby e streams and an LtRt when they're not even the international distributor.
They are the client, so they get to set their delivery specs. We just have to work with them - It's irrelevant why they want what they do, all we need to know is exactly what they want and deliver that.

As for simplification, all that will do (I think) is build in room for ambiguity and that would be a disaster - I'd much rather be working to strict specs than to fluffy ones with a moving target.....
Old 6th September 2011
  #18
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Quote:
Originally Posted by neilwilkes View Post
They are the client, so they get to set their delivery specs. We just have to work with them - It's irrelevant why they want what they do, all we need to know is exactly what they want and deliver that.

As for simplification, all that will do (I think) is build in room for ambiguity and that would be a disaster - I'd much rather be working to strict specs than to fluffy ones with a moving target.....
I'm allowed to have an opinion on their spec, doesn't mean i'm not going to adhere to it

In terms of simplification, I couldn't agree more. Make it strict and give me all the information I need, however......it's just been proven that they don't even state how dialnorm is measured, which could come under the definition of ambiguous could it not?

I think our job is not only to please the clients with good mixes that adhere to spec, but to also flag things in the correct manner when there is a problem. I for one would certainly appreciate that if I were them, but that's only my opinion.
Old 8th September 2011
  #19
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jahtao's Avatar
Quote:
Originally Posted by FullFrequency View Post
I fed the meter as LCR seeing as the dial channels are spread like that on their spec. I aimed purposely for -25 as at -23 it was too hot for the automated LtRt downmix. Even then the stereo was permanently sitting on 6ppm.
Lots of alarms bells ringing mate!!! : /
Old 9th September 2011
  #20
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Quote:
Originally Posted by jahtao View Post
Lots of alarms bells ringing mate!!! : /
Well that's what i thought too.... but it seems every show has passed... confused.com!

I did do another pass of dialnorm on it though and the reading came out the same whether LCR or 5.1 measurement, probably because I only tickled the surrounds.
Old 9th September 2011
  #21
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I had a similar issue with Discovery a few years back.Turns out they were using uncalibrated Analog inputs to a LM-100 which was in my case raising the level of my show by 2 dB which was putting me out of spec with both Dx norm and Peak level. A friendly call to the head of QC and it was all sorted out. As great as e-mail is, sometimes it just gets in the way when we are all trying to solve a problem.

Randall


Quote:
Originally Posted by jahtao View Post
So they've checked it again are now saying it does decode at the right level. I've wasted a day chasing this, ughhh. But fair enough these things happen.

Speaking to them I've also learned that when they QC loudness they only measure the centre channel. This is not the way the EBU R128 algorhythm was intended to be used, and this is not stated on their spec.

Ughhhhh : (
Old 13th September 2011
  #22
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Quote:
Originally Posted by quadraphonics View Post
out of spec with both Dx norm and Peak level.
Good old peak level!!! Missing you already : P
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