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Old March 13th, 2009, 05:09 PM   #1
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What do these cable TV specs mean?

I got my first TV spot. The local cable (Comcast) technical specs have a couple things I am not sure of:

"... minimum of 30 seconds 75% SMPTE color bars shall preceed ...":
Is this the FCP color bars at 75% opacity?

"A minimum of 1 second of video black shall precede and follow each spot/show. And a minimum of 6 seconds of stable video shall precede the spot/show."
I don't get the 6 seconds of stable video. The specs ask for 30 seconds of bars, a slate and a 1 second preroll. I'm guessing they don't count the bars and want the slate to be up for at least 6 seconds?

"Video levels shall be in compliance with test signals recorded at head of each tape, when corrected to those levels, content peaks shall not exceed 100 IRE nor black levels dip below 7.5 IRE"
I applied the FCP broadcast Safe filter making sure the "Clamp Above" setting was 100 for both Luminance and Saturation but I see nothing for black levels. Not sure if I need to do anything to ensure compliance with the bars at the head.

Any advice is appreciated. TIA
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Old March 14th, 2009, 12:26 PM   #2
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Here's some info that may help: SMPTE color bars - Wikipedia, the free encyclopedia

the stable video thing has me scratching my head, too

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Old March 14th, 2009, 01:54 PM   #3
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Originally Posted by Battle Vaughan View Post
the stable video thing has me scratching my head, too
I'm guessing that is a holdover from the analog and 3/4" video days when preroll was 5 seconds and people believed that an empty input was the same as black.
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Old March 14th, 2009, 04:06 PM   #4
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Quote:
Originally Posted by Les Wilson View Post
"Video levels shall be in compliance with test signals recorded at head of each tape, when corrected to those levels, content peaks shall not exceed 100 IRE nor black levels dip below 7.5 IRE"
I applied the FCP broadcast Safe filter making sure the "Clamp Above" setting was 100 for both Luminance and Saturation but I see nothing for black levels. Not sure if I need to do anything to ensure compliance with the bars at the head.
FCP Broadcast Safe DOES NOT correct for blacks below 7.5 IRE AFAIK. Bring up the video scope from the Tools menu in FCP and ensure that your black levels don't dip below 7.5IRE in your PROGRAM MATERIAL, not your bars. Bars HAVE a value of less than 7.5 IRE in the pluge.

ADDENDUM: I don't believe FCP Broadcast Safe addresses out of gamut colour completely either. You SHOULD watch the entire program with the Waveform and Vectorscope tools open and watch for IRE above 100 or below 7.5 on the waveform and any colour component that "overshoots" the "target box".
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Old March 14th, 2009, 04:13 PM   #5
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BTW, 75% bars are the ones that have the separate boxes and pluge at the bottom, NOT the straight bands of colour that prosumer cameras like the Sony PD150 and Canon XL1 generate.
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Old March 14th, 2009, 04:18 PM   #6
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Quote:
Originally Posted by Andy Tejral View Post
I'm guessing that is a holdover from the analog and 3/4" video days when preroll was 5 seconds and people believed that an empty input was the same as black.
EXACTLY. Black video is properly timed and continuous control track from your bars to your program material USING THE SAME SYNC. Lack of signal IS NOT timed, therefore NOT IN SYNC and can cause sync roll or tearing. The black or blue screen generated by a device not receiving a video signal is used solely to cover up the white noise that would normally occur on screen and again, has NO TIMING inherent in it.
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Old March 14th, 2009, 04:29 PM   #7
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All these replies were helpful and saved me rework. I got the bars right and the 3-way color corrector let me fix the blacks in a snap. With the Waveform tool up, I realized my slugs were below 7.5 too. I'm ignoring the stable video part. Thanks again.
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Old March 14th, 2009, 04:33 PM   #8
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Originally Posted by Les Wilson View Post
With the Waveform tool up, I realized my slugs were below 7.5 too.
COMMON mistake. Also, text in black is normally below 7.5IRE and SMALL text may not make a difference, LARGE main titles in black may be a no-no.
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Old March 14th, 2009, 04:48 PM   #9
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Yes. The slate was out of spec too.
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Old March 16th, 2009, 12:22 AM   #10
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Slight correction to your advice Shaun. On a waveform monitor digital video should fall between 0-100. 7.5 IRE is for analog NTSC video in the US only. Les, how are you delivering the spot? If it's staying digital (i.e. DVCAM via FW) then you don't have to worry about the black level changing. If you are delivering analog then you have to make sure that whatever device is doing the digital-to-analog conversion, such as a AJA or Blackmagic I/O card, is properly handling your black levels by adding setup so the analog output has a level of 7.5 and not 0.


-A
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Old March 16th, 2009, 05:26 AM   #11
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Quote:
Originally Posted by Shaun Roemich View Post
BTW, 75% bars are the ones that have the separate boxes and pluge at the bottom, NOT the straight bands of colour that prosumer cameras like the Sony PD150 and Canon XL1 generate.
You mean the EBU color bars, but these are also 100/75, which means white luminance is 100%, while chrominance is 75%.
Normal color bars (EBU or SMPTE) from nle programs and cameras are always 100/75, and this is what they mean with 75% color bars.

The SMPTE are the ones FCP creates in play out mode, the ones with the extra color boxes. They are also 100/75 on the color bar part.

You can create 100/100 EBU color bars with FCP from the "other bars and signals" menu, but you will see immediately these look way oversaturated.
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Old March 16th, 2009, 03:37 PM   #12
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Originally Posted by Andrew Kimery View Post
Les, how are you delivering the spot? If it's staying digital (i.e. DVCAM via FW) then you don't have to worry about the black level changing.
-A
Andrew: I delivered them digital (DV).

Heiko: My bars were FCP's "Bars and Tone" generators. Bummer. I guess I'll hear back from them if they won't accept them.

Thanks for the followups, at least I'll know what to do.

Last edited by Les Wilson; March 16th, 2009 at 03:38 PM. Reason: grammar
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Old March 17th, 2009, 10:00 AM   #13
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I am delivering a weekly talk show to a cable station here in Atlanta, in the form of video burned to MPEG2\DVD.

Their specs also listed the 7.5IRE requirement.

When asked, they apologized and said it's been a while since they reviewed those specs and since the whole process is digital (their equipment is also all digital), I should disregard that.
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Old March 20th, 2009, 01:31 AM   #14
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Just out of curiosity, now that things are progressing toward HD, are these requirements still needed? Is digital delivery solving any of these?
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Old March 20th, 2009, 05:57 AM   #15
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No matter the format or delivery method... SD, HD, Tape, file transfer,
A broadcast commercial still needs to conform to a broadcast spec.
If you are providing broadcast content, it is your responsibility to make sure you know these specs, and that the content you provide meets these specs.

I can't tell you how many commercials during political season fail the QC because the production house doesn't know how to make a disclaimer 21 scan lines.
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