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Even Network QC gets it wrong sometimes.

COW Blogs : walter biscardi's Blog : Even Network QC gets it wrong sometimes.

So I've been dealing with several issues with an international network that has a primarily European distribution area. We seemed to have everything worked out this morning and suddenly I get a notice from QC that our audio was suddenly rejected as being 8db too hot. 8db too hot!

I'm completely dumbfounded. How can audio on this show, which was professionally mixed, be 8db too hot? We've already delivered three episodes and each passed QC with flying colors and suddenly we screwed up this big?

Of course I check the timeline first and foremost. Tone is -20db, Check. Main show audio rides around -12 to -10db with a few peaks at -8db. Check. Now I check the show we shipped last month. It matches. I check the the other two shows delivered in November and January, they match too. Now if we're 8db over -8, I guess we'd be hitting distortion hell at digital 0 so that would sound pretty bad.

I call my audio designer, Patrick Belden, whom you fans of Good Eats would know as the sound designer of every episode of that series. He brings up the show and a previous episode on his sound system and it all matches there. He's at a loss to explain what could have happened.

So I check in with PostWorks in New York. They handle the 1080i/60 to 1080i/50 conversion for us. Could they have done anything at all that caused our audio to suddenly rise by 8db? This seems unlikely because it's just an SDI transfer from one deck to the other through a Terranex or like converter. Not only does PostWorks take a look at our master in the tape deck, they bring the master into a sound sweetening suite and check all our levels. Everything is spot on to spec.

So I ask the network again, "You say we're 8db too hot, can you please tell me exactly what level we're hitting? -2? -4? 0?" I am going to quote the QC person here on the response:

"Walter the audio level was 4 to 8dB too hot. That means instead of being at -20dB they were between -16 to -12dB. This wasn’t the peak it was the mean. The audio consistently peaked around -12dB. This is all in the digital world so -12dB is 8dB too hot."

Folks, do you see the bold areas? -12db in the digital world is too hot. I really don't know where this QC person got their information and I'm not even going to tell you what my response was to all of this, but suffice it to say, at this point I stopped trying to explain anything. I instructed the Executive Producer of the show to have an engineer explain audio levels as I was not going to.

So folks, in this ever changing world of high definition TV, globalization and what-not, sometimes even the folks reviewing your shows at the networks can get it wrong. I guess it's too much information even for the technical folks.

Posted by: walter biscardi on Mar 23, 2007 at 7:42:01 pmComments (10) editing, hd, final cut pro


strange but true :-) thanks
by Andy Mees
strange but true :-) thanks Walter
An update
by walter biscardi

Well, first of all to the comments above, yes the specs are available in written form and I do have a copy of them here, have had them since before we started the series.  However, they appear to have been written 20 years ago for analog SD broadcast and never updated.  For instance, they called for three step tone during Bars which my sound designer has not done for over 15 years.   This network was launched as an HD channel only from the ground up so much of our first two months was trying to figure out exactly what what truly going to apply to the digtal HD world and what was going to be ignored.  The three step tone requirement was quickly thrown out.

So what we did with our very first episode was to create the sound mix exactly as we deliver to US HD networks.  Our sound designer, Patrick Belden, has delivered all 10 seasons of Good Eats so he knows exactly what he's doing with the mixes and how they need to be delivered to networks.  Our first episode fully passed QC and they commented on how good everything looked and sounded, so we figured we were good to go.

It was only with our latest episodes that somebody decided we were far out of the original analog SD specs and we need to adjust on our end.   So as it stands right now, here are the new specs for which we are to deliver.

Tone set to -20db digital.  Audio to peak NO HIGHER than -16db digital.  This is going to be lowest audio we've ever shipped out from the shop, but what are you going to do?  If that's what they want, then that's what they get! 

I see where you are coming
by Andy Mees
I see where you are coming from Christian, apologies to both yourself and Walter if I was less than clear.

What I had intented to suggest was that just because delivery specs (either in print or online) were not mentioned does not necessarily mean they were not actually available or indeed given as part of the commissioning process as would normally be the case... we are both making an assumption on this point.

Lets face it, only Walter knows, and its his right not to comment.

Bottom line, specs available or otherwise, Walter is simply telling us that he judged those specs to be wrong. My comment was simply that wrong or otherwise the onus is on us to deliver according to the specs. And of course, try to get the specs changed! [grin]
by Christian Glawe


When the QC person told Walter this:

"Walter the audio level was 4 to 8dB too hot. That means instead of being at -20dB they were between -16 to -12dB. This wasn’t the peak it was the mean. The audio consistently peaked around -12dB. This is all in the digital world so -12dB is 8dB too hot." came as a surprise to him. In fact, nowhere in this chain of events (as described) is there any reference to specs being in print and/or on-line.

"Pain is temporary... film is forever"

Christian Glawe


goodness, what on earth
by Andy Mees
goodness, Christian, what on earth makes you think the tech specs are not in print and/or are not available online?
Tech specs over the phone are dubious at best
by Christian Glawe


Really, it's the responsibility of the broadcaster and/or distributor to have full tech specs *in print* or, at least, *on-line*.

Personally, I would not take tech specs given over the phone as gospel.  If someone told me over the phone that audio peaks were to be at -16db, I would immediately ask for some sort of documentation. 


"Pain is temporary... film is forever"

Christian Glawe


yeah but Walter, as you very
by Andy Mees
yeah but Walter, as you very well know, the tech specs are not yours to decide.
when you deliver to a network it is your responsibilty to check and adhere to their specs for delivery, regardless how daft they are ...

... now that said, beleive you me I am with you on this. i waste hours talking to filmakers/production houses trying to explain to them why their perfectly good audio has "failed" QC

the bottom line tho is that our tx specs call for a maximum peak of -16db, hence the delivery specs also call for a maximum peak of -16db, so as to minimize the need for "fixing" commisioned work to make it ready for tx

its all unecessarily painful but there you are
That the QC guy was new on
by walter biscardi

That the QC guy was new on the job, and assumed that, since tone was at -20 db, then that's where the peaks should be, too!


Believe it or not, the network specs call for peaks at -16.  Way off base.  That's why they're looking to change everything now! 

I'll bet...
by Christian Glawe


That the QC guy was new on the job, and assumed that, since tone was at -20 db, then that's where the peaks should be, too! 


"Pain is temporary... film is forever"

Christian Glawe


As a follow-up, now the
by walter biscardi
As a follow-up, now the technical department is looking to update their specs.  They told me the other day that I'm not the only one telling their specs are a tad off.

Professional Video Editor, Producer, Creative Director, Director since 1990.

Credits include multiple Emmys, Tellys, Aurora and CableAce Awards.

Creative Director for Georgia-Pacific and GP Studios, Atlanta. Former Owner / Operator of Biscardi Creative Media. The show you knew us best for was "Good Eats" on the Food Network. I developed the HD Post workflow and we also created all the animations for the series.

Favorite pastime is cooking with pizza on the grill one of my specialties. Each Christmas Eve we serve the Feast of the Seven Fishes, a traditional Italian seafood meal with approx. 30 items on the menu.

If I wasn't in video production I would either own a restaurant or a movie theater.



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