Saturday, July 12, 2014

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

 

I can tell blanking right in the Avid Source Record monitors.  When a shot is in question I blow it up till I no longer see the black edges change in width at the edge of the display.  I always bump it one more to make sure I'm not missing anything.  It's been a fast and reliable way for me.  I also try to find the size adjustment on any big LCD/Plasma in the room and make sure they aren't it an overscan mode.

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Posted by: bigfish@pacbell.net
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Re: [Avid-L2] QC Quote of the day

 

I believe Steve Holmes is one of the people that might have led me in the direction that there is no longer a spec per say.  Given the QC operator sited what he suggested was a camera hood in the edge of the frame and called it a blanking variance makes me wonder if he/she really knows what blanking really is.  A camera hood is a framing error not a blanking error.  Oh well I'll have to break out my engineering book to refresh the numbers of the specs in my head.  IIRC Tektronix has a pretty good site with the most important particulars.



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

' I'm curious why I've not seen an exact number for this duration.'
because the number depends on format. It's in the SMPTE274 standard and the QC house knows what it is.

you can also ask your pal at Tektronix.

cheers,
BG



From: "bigfish@... [Avid-L2]" <Avid-L2@yahoogroups.com>
To: Avid-L2@yahoogroups.com
Sent: Saturday, July 12, 2014 11:05 AM
Subject: Re: [Avid-L2] QC Quote of the day

 
Yes they will but do you know of an exact spec like the old composite days?  I can look at Y in a two line display and measure from end of active picture to start of active picture.  I'm curious why I've not seen an exact number for this duration.  Perhaps I've mis interpreted the things I've heard.


---In Avid-L2@yahoogroups.com, <DennyD1@...> wrote :


On Jul 11, 2014, at 11:17 PM, Mark Spano wrote:

> 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.

I offer:

That's what 'scopes are for.  A waveform scope will accurately show you what is part of the picture and what is not.

Dennis Degan, Video Editor-Consultant-Knowledge Bank
    NBC Today Show, New York




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Posted by: bigfish@pacbell.net
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Re: [Avid-L2] QC Quote of the day

 

I even brought our mixer into my bay and we tried to try the track based RTS Compressor Limiter thingy, can't remember the exact name.  We set compression to max of  100. something to have infinite compression and set threshold to -6 and still there were spikes on some of the stems.  Ultimately I aaf'd the tracks back to protools and he put on his brick wall limiter, not sure what he is using for that, and that corrected the problem.  I go back to DBX 160 limiters with the 4 main knobs I understood functionally.  I see the same kind of controls: compression ratio, threshold, attack and release but it is a pain having to loop and tweak in Avid and it seemed to confound our mixer even when we dialed in the numbers he desired.  I rarely deal with audio other than reference mixes so my chops are thin.  No matter how I slice it dealing with audio in avid in a sophisticated manner is clunky at best.  Perhaps the Ver. 6 and 7 tools are implemented a little better but I've yet to spend any time in V7.

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Posted by: bigfish@pacbell.net
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Re: [Avid-L2] QC Quote of the day

 

Yeah but QuickTime 7 at 1:1 pixels on a monitor capable of showing greater resolution than 1920x1080 is reliable and accurate. That's why I suggested it, since you're seeing the full active picture area without any over/under scanning or cropping or bezel interference.

I understand how scopes work and use them all the time in my work. But for this specific type of checking, you need to see exactly where the boundary ends, and while the scope can measure beyond the active picture boundary, there's no easy determination or fine enough resolution to know reliably where that is, unless you have a giant scope monitor that can show scale lines reliably enough to match your vision. All of that headache is avoided with the QT method. Or use AfterEffects, same result. I only suggested QT7 because pretty much everyone has this available or can get it available on a Mac with high enough screen resolution.


On Sat, Jul 12, 2014 at 5:15 PM, Dennis Degan DennyD1@verizon.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:
 


On Jul 11, 2014, at 11:17 PM, Mark Spano wrote:

> 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.

I offered:

> That's what 'scopes are for.  A waveform scope will accurately show you what is part of the picture and what is not.

On Jul 12, 2014, at 2:05 PM, bigfish@pacbell.net wrote:

> Yes they will but do you know of an exact spec like the old composite days?  I can look at Y in a two line display and measure from end of active picture to start of active picture.  I'm curious why I've not seen an exact number for this duration.  Perhaps I've mis interpreted the things I've heard.

I respond:

I honestly can't answer that one either. Part of the reason might be related to the fact that since everything is digital now, there's no actual duration for the sync pulses. Heck, there ARE no actual sync pulses! That info is all in the data stream now.
So, you look at a waveform scope of the digital Y signal and try to find where the picture starts and ends. That's the best I can do . . . ;) But it's got to be more reliable and accurate than going by a picture monitor. Monitors can vary, each one from the next.

Dennis Degan, Video Editor-Consultant-Knowledge Bank
    NBC Today Show, New York



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Posted by: Mark Spano <cutandcover@gmail.com>
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Re: [Avid-L2] QC Quote of the day

 


On Jul 11, 2014, at 11:17 PM, Mark Spano wrote:

> 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.

I offered:

> That's what 'scopes are for.  A waveform scope will accurately show you what is part of the picture and what is not.

On Jul 12, 2014, at 2:05 PM, bigfish@pacbell.net wrote:

> Yes they will but do you know of an exact spec like the old composite days?  I can look at Y in a two line display and measure from end of active picture to start of active picture.  I'm curious why I've not seen an exact number for this duration.  Perhaps I've mis interpreted the things I've heard.

I respond:

I honestly can't answer that one either. Part of the reason might be related to the fact that since everything is digital now, there's no actual duration for the sync pulses. Heck, there ARE no actual sync pulses! That info is all in the data stream now.
So, you look at a waveform scope of the digital Y signal and try to find where the picture starts and ends. That's the best I can do . . . ;) But it's got to be more reliable and accurate than going by a picture monitor. Monitors can vary, each one from the next.

Dennis Degan, Video Editor-Consultant-Knowledge Bank
    NBC Today Show, New York


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Posted by: Dennis Degan <dennyd1@verizon.net>
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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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Re: [Avid-L2] Vanishing Waveforms

 

I have had the same intermittent issue only with AMA linked and only on some media. YES the audio sample rate is correct and matches the project rate - as soon as I transcode grrr...really I have to transcode :-( 
The audio waveforms appear. 

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Posted by: Jeff Krebs <rockinjeff@gmail.com>
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Re: [Avid-L2] Vanishing Waveforms

 

Good advice, Steve. I'm the king of back-ups in every way except user settings. I definitely need to discipline myself on that front.

Thanks,

DD

David Dodson
818-523-0905

On Jul 12, 2014, at 11:54 AM, "Steve Hullfish steve4lists@veralith.com [Avid-L2]" <Avid-L2@yahoogroups.com> wrote:

 

David - corrupted user settings happen on a fairly regular basis. Sometimes small behaviors that you might THINK are just normal are even caused by them.


You should really keep your settings on a flash drive or - better yet - burned to a DVD or two where they can't get corrupted. Then it only takes about a minute to recover.

But I feel your pain and understand your frustration.

Steve

On Jul 12, 2014, at 2:32 PM, David Dodson davidadodson@sbcglobal.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

 


I tried all the suggestions, but in the end, only creating a completely new user did the trick. Real pain in the ass.

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Posted by: David Dodson <davidadodson@sbcglobal.net>
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Re: [Avid-L2] Vanishing Waveforms

 

David - corrupted user settings happen on a fairly regular basis. Sometimes small behaviors that you might THINK are just normal are even caused by them.


You should really keep your settings on a flash drive or - better yet - burned to a DVD or two where they can't get corrupted. Then it only takes about a minute to recover.

But I feel your pain and understand your frustration.

Steve

On Jul 12, 2014, at 2:32 PM, David Dodson davidadodson@sbcglobal.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

 


I tried all the suggestions, but in the end, only creating a completely new user did the trick. Real pain in the ass.

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Posted by: Steve Hullfish <steve4lists@veralith.com>
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Re: [Avid-L2] Re: Vanishing Waveforms

 


I tried all the suggestions, but in the end, only creating a completely new user did the trick. Real pain in the ass.

Thanks, everyone!

DD


On Jul 12, 2014, at 11:13 AM, bigfish@pacbell.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

I've seen some strange behaviors fixed by trashing the .avs folder in the project folder and letting avid rebuild it.  I haven't had your exact problem but it might be worth a shot.  Before doing this your could try opening a new project and opening the bin in question and see if the audio waveforms behave.  If they do then move the .avs folder out of the project and see what happens when restarting the original project. HTH



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Posted by: David Dodson <davidadodson@sbcglobal.net>
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[Avid-L2] Re: Vanishing Waveforms

 

I've seen some strange behaviors fixed by trashing the .avs folder in the project folder and letting avid rebuild it.  I haven't had your exact problem but it might be worth a shot.  Before doing this your could try opening a new project and opening the bin in question and see if the audio waveforms behave.  If they do then move the .avs folder out of the project and see what happens when restarting the original project. HTH

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Posted by: bigfish@pacbell.net
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Re: [Avid-L2] QC Quote of the day

 

' I'm curious why I've not seen an exact number for this duration.'
because the number depends on format. It's in the SMPTE274 standard and the QC house knows what it is.

you can also ask your pal at Tektronix.

cheers,
BG



From: "bigfish@pacbell.net [Avid-L2]" <Avid-L2@yahoogroups.com>
To: Avid-L2@yahoogroups.com
Sent: Saturday, July 12, 2014 11:05 AM
Subject: Re: [Avid-L2] QC Quote of the day

 
Yes they will but do you know of an exact spec like the old composite days?  I can look at Y in a two line display and measure from end of active picture to start of active picture.  I'm curious why I've not seen an exact number for this duration.  Perhaps I've mis interpreted the things I've heard.


---In Avid-L2@yahoogroups.com, <DennyD1@...> wrote :


On Jul 11, 2014, at 11:17 PM, Mark Spano wrote:

> 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.

I offer:

That's what 'scopes are for.  A waveform scope will accurately show you what is part of the picture and what is not.

Dennis Degan, Video Editor-Consultant-Knowledge Bank
    NBC Today Show, New York




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Posted by: Bogdan Grigorescu <bogdan_grigorescu@yahoo.com>
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