Well the ABC New York Tech Spec sheet list the RGB primary settings for the Harris family of legalizers as min=-35mV max=735mV. I run my legalizers and safe color limiter effect at 16-235, aka 0mV to 700mV and have virtually never had QC level issues. I've found that most QC work I've had done in Hollywood area seems to not report much in the way of scope logged errors which leads me to believe most QC isn't relying on error logging. Given the Codec/Compression errors in HDCam and HDCamSR and the addition of alarm raising speculars created by the enhancement circuitry in those machines on playback it really makes it hard to trust the error logging in the real world. I like to run my shows through it on output with the 1% area just to be safe. I mean what's a boy to do when the show runs clean on error logging at 0% area out of the Avid but when monitoring the Record machine the alarms go nuts? That's why I've been instructed by the Tek folks to scope the machines with 1% area. I love hearing the various takes on this so I can better understand what I can do to improve my workflow but at some point I've got to just make it Red and roll to record error alarms be damned and get things on the air. Now a precise description of what image problems really result from the specular excursions would be interesting as from my experience they basically amount to no harm no foul.
--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
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> Unfortunately, most QC houses will look for a -5mV to 705mV legal excursion(including spikes), so you'll have to customize your trigger levels in order to become 'QC safe'
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> As for the Tek area, keep in mind that 1% means splitting both H and V in ten equal patches, which is a 3"x4" patch on a 50" display. Anything less than that goes unnoticed(or not logged by Tektronix), but could be objectionable in a QC process.
> I asked for a finer adjustment(like in.1% increments) from Tek for years, but they won't budge. Both Steve Holmes and Mike Waidson know about it.
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> BG
> www.finale.tv
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> --- On Fri, 10/26/12, johnrobmoore <bigfish@...> wrote:
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> From: johnrobmoore <bigfish@...>
> Subject: [Avid-L2] Re: Red Epic yields specular excursions above 700mV?
> To: Avid-L2@yahoogroups.com
> Date: Friday, October 26, 2012, 9:59 AM
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> On the diamond display High= 721mV, Low=-21mV, Area=0%
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> This is Tektronix default although in later software updates the same wfm 7020 defaults to area=1%, I believe this is due to a lot of over zealous alarms especially when error logging an HDCamSR or HDCam tape as in my experience their codec/compression anomalies will light up a area= 0% like a Xmas Tree where as the same setting on the Avid out are clean. The QC folks were looking at the waveform specular spikes and not complaining about scope registered errors. They have since backed off, maybe we just beat them down, but I would like to know what actual consequence these spikes could cause. Steven Holmes from Tektronix mentioned that the pixel to pixel extreme transitions will exceed the bandwidth and cause the spike which can wreak havoc on Mpeg encoder/decoders that will soften the image among other things when it tries to compensate for the bandwidth/transition spikes. Man some days I just want composite video again and a freaking dual track
> scope and my trusty tentilometer. ;-)
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> --- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@> wrote:
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> > John, what were your alarm trigger levels for RGB gamut/ luminance and composite levels(arrowhead) set to? I believe they default to EBU103.
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> > BG
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> > www.finale.tv
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> > --- On Thu, 10/25/12, johnrobmoore <bigfish@> wrote:
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> > From: johnrobmoore <bigfish@>
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> > Subject: [Avid-L2] Re: Red Epic yields specular excursions above 700mV?
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> > To: Avid-L2@yahoogroups.com
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> > Date: Thursday, October 25, 2012, 11:06 PM
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> > The scope is a Tektronix WFM 7020 set to Tektronix defaults with 0% area tolerance. More recent versions of the scope software have default set to 1% area tolerance on the diamond display. I use the 1% area for error logging off tape and 0% for error checking the Avid output. Codec/compression induce off tape errors make the alarm mis-trigger when playing back of HDCam and HDCamSR. I was seeing no alarms with 0% area tolerance which is why I feel the specular excursions are a non issue. Ultimately it passed QC but I think it's only because we beat up the QC guys and called their bluff when they tried to tell us the "Alchemist" was the only piece of gear they had that would correct the so called issue. I asked if they had a Harris DL-860/850 and they said they didn't. I found that unbelievable given they are a large Hollywood dub house. The Harris/VideoTek DL-860/850 is pretty much an industry standard around here for legalizers and most
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> > networks and cable networks will give you their settings for delivery specs. That's what seemed fishy when talking to the QC folks especially sense I've delivered countless shows with the same legalizing and never had an issue. The only thing new is the Red Camera and the fact that many of the dub houses have started to promote using their Alchemists for what seem to be non issues but they claim they have to run the shows through Alchemist. I'm just trying to be an informed consumer conscientious editor. So far no one has told me what ill effects the specular spikes cause. It looks fine on all my monitoring gear. After all every head end has a proc amp/legalizer on the uplink feed. Oh well I'll just send more bananas with the next master.
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> > --- In Avid-L2@yahoogroups.com, John Beck <jb30343@> wrote:
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> > > John, High frequency stuff has a habit of sneaking through the safe
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> > > settings. Hope this helps. --J.B.
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> > > John Moore wrote:
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> > > > The Red multicam shoot I posted about was onlined by someone else and even with the safe color limit effect set to 16-235 422 checked and an outboard legalizer there are still specular spikes well above 700 mV. They don't set off my scope alarms but QC is sqwaking. Is Red more prone to this. Raw media was consolidated using the camera metadata seeing and full debayer to DNX 220. I've heard Red's "rich" colors make it more prone to the specular excursions. Can anyone confirm or deny this. We're being told they need to use Alchemist to fix it and this starts to seem like the ABC Spike Gate scam, but I'm willing to be educated. I feel like if my scope doesn't alarm it's a non issue. Curious what others have to say.
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> > > > John Moore
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> > > > Barking Trout Productions
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> > > > Studio City, CA
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> > > > bigfish@
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> > > > ------------------------------------
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> > > > Search the official Complete Avid-L archives at: http://archives.bengrosser.com/avid/
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> > > > Yahoo! Groups Links
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