Dave Friend
Forum Replies Created
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[Ron Moody] “I accept your statement but where does it come from?”
It comes from a number of sources. First is SMPTE RP155 (a technical document) which specifies the reference level for digital audio as -20dBfs. Every network that I have delivered to (multiple broadcast and cable networks) adheres to that standard. These networks also typically spec that -9dBfs is the maximum peak allowable. Sometimes, they vary by a dB or so. For instance, ABC allows a max peak of -8dBfs if I recall correctly. Send a tape outside these specs, by even a tiny bit, and it will come back in a hurry having failed the tech evaluation. (Europe and some other parts of the world use a slightly different reference level.)
As it turns out (probably not an accident) using these levels as indicated by a digital peak meter will result in a digital to analog (audio) conversion that mostly works perfectly. I say mostly because if your material is highly compressed, say with lots of peaks between -9 and -12 for sustained periods of time, then the analog will be too hot.
There was a thread on this forum some months ago where I went through this with someone else. Read that thread for more details. There is a link in that thread to a website with a lot of technical info on how the different methods of measuring audio levels relate to each other. Unfortunatly, that link now appears to be dead. I will try to find a new link and will post it here if I succeed. Maybe this link or this link will prove useful. They kind of cover the same info the old link did but they are not as easy to read.
[Ron Moody] “I haven’t heard any distorition with levels set there.”
You will not until the level attempts to go beyond 0dBfs which is the absolute max that a digital source will allow. There aren’t any bits left to represent a volume beyond that level. IOW, there is no such thing as +4dBfs in the digital world. As long as your monitoring setup will handle the output sent to it and the meters stay under 0dBfs, there will be no distortion. Not any due to gain settings at any rate.Hope this helps.
Dave
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Ron,
Most of what you are seeing is due to the different metering system in PPro and on the Beta deck. The 1800 is showing you analog VU levels and PPro is showing you digital peak levels. VU is sort of a running average and, as such, simply won’t display the peaks the way that a digital meter does. Those are showing the precise level at any given instant.
There is a SMPTE standard for reference audio from digital sources that specifies a level of -20dB.
Try this:
First, your program material should NOT exceed -9dB on the PPro meters. This is kind of hard (OK, damn near impossible) to do accurately with PPro because of the crude way Adobe chooses to display audio levels. But if you set levels so that someone speaking with a “normal” voice peaks around -12, and that the loudest peaks don’t go more than halfway to -6 on the PPro meters you will be pretty close.Second, set the tone to -20dB on the PPro meters. Adjust the 1800 record level to 0VU from this tone.
You will find that reference tone and program levels will be pretty much in line. Really, this does work and is standard industry practice.
Hope this helps.
Dave
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[nicotone.com] “Is this right?”
Yup, sounds about right. The Animation codec is pretty close to uncompressed and carries an alpha channel to boot. An hour long segment would probably run well over 72GB.
What format is the project set for? Is this a DV project? You should be able to get a good quality DV format quicktime from a PPro project that is set for DV format.
Dave
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Nico,
When viewing a mov file using the QuickTime player be sure to set the movie’s properties to use “High Quality Enabled”. Often the file will look horrible but it is only due to this setting of the player.
Hope this helps.
Dave
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You can choose File | Close to put away the current project and be presented with “Recent Projects” list.
Dave
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You need to give the bitrate calculator the total length of all video that will be on the disc.
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Tim,
Do you agree that the purpose of timecode is to assign a unique value to every frame of a 24 hour period?
Dave
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I am sorry to say that Mr. Kolb is wrong. For every SMPTE nondrop frame timecode value there is a corresponding and immutable drop frame timecode value – no ifs ands or buts.
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[Timothy] “I understand SMPTE code”
Yet the rest of your statement indicates you do not.
[Timothy] “Otherwise the drop / non drop differential on an hour seven tape starting at 7:00:00:00 will be 25 seconds when it should be zero,”
No, the offset should not be zero. The DF/NDF offset is NOT a function of when the tape started recording. The offset begins to accumulate at 00:00:00:00, not at some arbitrary time value. 07:00:00:00 NDF = 07;00;25;06 DF no matter when the recording began.
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[Timothy] “But in the case of capture the tapes are in exact agreement at the beginning of hour seven, to use the example.”
No, they are not. 7:00:00;00 DF and 7:00:00:00 NDF are not the same value. It does not matter how long the tape has been running, the time value of hour seven is explicitly defined by the SMPTE standard according to the TC format in use. This is the way SMPTE has defined the standard. Adobe is simply following it.
[Timothy] “the way in which Premiere changes my non drop code to drop frame when I change the program settings or import a project with different settings follows a logic I have yet to fathom,”
As I said earlier, I have not had to deal with mixed TC formats in V2 yet so I cannot make informed comments. From the quick test I did, it seems that Ppro assumes that the value you enter for a New Item | Offline File is in the same TC format that the Project is using as the