Saturday, July 12, 2014

Re: [Avid-L2] QC Quote of the day

 

Depends on the limiter being used, but there are a lot of ways setting a ceiling of -6.0 dBFs can allow values above that through. Particularly with the L1 and L2, these always let values over the ceiling through unless set in a very specific way. This is why I always advocate for a True Peak limiter, as these are clamps by design. 

On Saturday, July 12, 2014, bigfish@pacbell.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

 

According to our mixer his his limiters on the tracks and then a brick wall limiter at -6dBFs, which is the network spec.  I know my video legalizer lets specular spikes sneak through but I've never heard of that in audio.  I really think there is too much speculation going on with the assessment.  It never hurts to take a second look or listen.  Our mixer decided to brick wall at -7 dBFs for the sections flagged.



---In Avid-L2@yahoogroups.com, <cutandcover@...> wrote :

I agree about what QC should do. They should either cite everything, or cite what they do, but don't give vague 'alerts' - you have every right to complain about this, or ignore it.

For a -6 dBFs peak, network spec could be interpreted sometimes to mean either (A) -6 dBFs is the maximum allowable peak (OK to hit this but not go over) or (B) -6 dBFs is the error line (anything under -6 is OK but -6 and over are NG). I hate these vagaries myself and mostly err on the more cautious side. Any audio mixer for post has tools that can very easily limit on a specific dBFs value so nothing goes over - for this kind of thing I'd set the Avid Pro Limiter (which limits True Peak) to clamp at -6.1 dBTP which would cover both True Peak and dBFs peaks. Easy peasy. Most loudness plugins now contain True Peak limiters so that should be a part of every audio mixer's toolkit.


On Fri, Jul 11, 2014 at 11:51 PM, bigfish@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:
 

You make a valid suggestion and I did just that although my QC was at best a fast pass that focused on making sure the problem shots weren't repeated in Open Teases and bumpers.  I found a few extras.  I just feel it's a half assed QC if they say in their report we might not have seen all the problems.  Isn't seeing and noting the problems their job as a second set of fresh eyes focused on looking for image flaws?  I barely get enough time to get shows conformed and color corrected.

Also comments on audio peaks at -6dbfs, which is the network spec. are noted as boarder line?  In my book it's either in spec or not this is not an iffy call.  Don't know what they are monitoring with but the audio is correct in our protools bay with all his metering he can tell.  Seems the QC guys are speculating on a cautious side but in my mind it's creating unnecessary work, but hey I'm glad to be working so it's all good in the end.

Funny "in the end" is pretty much how I would describe today's events.  Unfortunately it was my end!!! ;-)



---In Avid-L2@yahoogroups.com, <cutandcover@...> wrote :

Honestly, you can fix what they cited, then do a QC pass yourself to see if you find anything else. That's the best I would offer here. As far as what they're calling 'blanking', I've had people cite this when they actually mean 'active picture area', in other words, everything inside the 1920x1080 bounds. This can be hard to spot, especially on monitors that have black bevels, since what you're looking for is a line or two of black around the edge. For that kind of QC, I find what works is to find a Mac that has a greater than 1920x1080 screen resolution. Make a QT and open it there, make it full size (1920x1080), and make a full white desktop background with as few icons as possible. There you can skim in QT7 (*not* QTX) and spot any scenes that don't fill to the edge of the frame (that are supposed to).




On Fri, Jul 11, 2014 at 2:48 PM, bigfish@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:
 

We were not involved in this QC as it was done by the network just for the international version.  Mind you the domestic version has the same "issues" and was not flagged by their QC department nor were they by the QC company we used prior to delivering the show.

The point of QC is to list the errors they find and not speculate that there are more that they didn't catch.  I understand about the degree of scrutiny a QC gets being dependent on how much the client wants to pay.  Some times I see that mix minus vo tracks are only spot checked etc....  I guess I just feel that if the network feels a second QC is warranted for international it should flag everything that the network deems important.  Now if the network is okay with "SOME (NO ALL) EXAMPLES" being fixed that is what they are going to get.

I also like the blanked statement that "blanking in this section varies, may be camera hood".  A fair assessment but IIRC there is no official blanking spec in the new digital world.  There is nothing like the 10.9 to 11.2 micro seconds from the days of yore.  I realize excessive blanking still can show up as black on the edges but is there really no official spec guidelines?  I've been led to believe from threads here and other discussions it is not longer a spec.  Am I confused about this.



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Posted by: Mark Spano <cutandcover@gmail.com>
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