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shadow
08-27-2004, 04:27 PM
I'm trying to figure out what audio level to use when I'm mastering my edit to tape or have to export it directly to DVD. After some googling, I have found some information, but I want to verify it and know what method to use:

What I found was that because digital audio clips at 0dB, you need a certain headspace. There are two different standards. The first (american standard) is a reference of -20dB with a maximum of -10dB. The second is the European standard with a reference of -18dB with a maximum of -9dB.

I'm in a European country, so it would be logical to use the -18dB method. But I also heard of european companies using the -20 method or use -12 or even -20 as a maximum level.

So, I'm confused. What should I use when I'm exporting to tape or more important, when the file goes straight into my DVD authoring program?
Tagger
08-29-2004, 11:03 AM
i'm not an expert, but i think that the differences are in wether your exporting for broadcast or not, broadcast is mastered at +6 dBu which gives you the -9 headroom in the digital format ... but other stuff is mastered at 0, +4 or +8.
if it were up to me, i'd go for the -18.

but like i'm just a student, so dont listen to me :P
djx
09-01-2004, 03:44 PM
Does anyone know the Australian standard?

We have been using -20db ref, -6.6db max when outputting to digital betacam for broadcast. Masters we make are not rejected, but its hard to get any authorative confirmation that this is the "standard".

What would be the reasons for choosing a lower max level?
The Found Vertex
09-02-2004, 08:13 PM
The lower max level is to save for intersample peaking. It possible in some high-frequency content to have sound that is significantly louder between samples than in samples. -6.6db is a safe place. Unfortunately most cd's wont go by this standard and are squashed to high-heaven.

Also the rms at -14db below peak is reasonable. There's no nee to increase your crest value, else you will be victim to all sorts of distortions and whatnot.
The Found Vertex
09-02-2004, 08:17 PM
Also, digital audio does not "clip" at 0db. Clipping is a little more involved than that. multiple samples in a row at the same position are "clipped" as you hear them. Also it's possible to have clipping occur below 0dbFS sample peak as I noted above.

at 0dbFS, you cant have peaks go above that. But during the DA conversion process there certainly will be sound above and below from reconstruction of the waveform. (it's NOT connect the dots)
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