Well I guess now you can buy a Teranex for a couple of grand they better be capable of something else. Out of curiosity, has anyone done any comparisons between the two standards converters? Is an Alchemist worth it any more?
Andi
To:
Avid-L2@yahoogroups.com
From:
bigfish@pacbell.net
Date: Fri, 26 Oct 2012 16:50:40 +0000
Subject: [Avid-L2] Re: Red Epic yields specular excursions above 700mV?
I've never operated an Alchemist so I can't answer how it legalizes the excursion spikes. Over the last year there have been changes in some QC issues most notably ABC started rejecting shows that had spikes outside active video which seem to have no effect on the image in HD but they claimed that some set top box DTV converters would display a white edge on the letter box caused by these spike. There suggested solution was to run the show through an Alchemist because it would eliminate the spikes. Legalizers only effect the active video signal so the spikes in the blanking interval would not be corrected by a legalizer. From that time on various dub/QC houses have started flagging what seem to be non issues claiming they need to run the show through their alchemist to get rid of the problem. Perhaps the Alchemist completely replaces the Hanc and Vanc like an old composite Proc Amp did. As far as removing excursion spikes I don't have anything but the word of the dub house that the alchemist can do that. As I said I was truly shocked when the dub house said they didn't have a Harris DL-860/850 in house. This seems odd given it's broad use around town and the defacto legalizer of choice by many networks. I too would like to know more about the Alchemist's use in this scenario. You say it's main use is standards conversion but I think some dub houses are using it for profit conversion to get the clients to pay more to fix what seems to be a non issue. I could be wrong about the non issue of the specular excursions but my Tektronix contact looked at scope screen grabs and said the looked like the typical transition spikes. He added there is a "data option" for some tektronix scopes that will tell you the exact digital data level without the analogue interpretation that causes the apparent spikes on the waveform.
--- In
Avid-L2@yahoogroups.com, Andi Meek <kwikpasta@...> wrote:
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> John,
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> Pardon my ignorance, can you explain why/how you would use an Alchemist to legalise? I thought they were just a standards converter? At least that's all I've ever used them for. If they have this extra talent, why would they prefer that over a dedicated legaliser like an Eyeheight?
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> Andi
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> To:
Avid-L2@yahoogroups.com
> From: bigfish@...
> Date: Fri, 26 Oct 2012 06:06:11 +0000
> Subject: [Avid-L2] Re: Red Epic yields specular excursions above 700mV?
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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 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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> > color effect. The only way I've found of eliminating the excessive
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> > might be some outboard legalizers that will catch it. Not sure why your
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> > scope's alarms aren't going off. You might want to check your scope's
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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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> > > Search the official Complete Avid-L archives at:
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