Ken Landers wrote:
In years past, a number of systems has issues with intra-sample
peaks. While a technical 0 dBFS cleared, the interpolated level
between the peaks would cause distortion. From a best practices for
broadcast point of view, my colleagues and I have just tried to steer
clear of any overs, sample-wise or interpolated. We started working
to -20 dBFS RMS as a matter of course. With the general move to 24
bit from 16 it's never presented any real issues.
And as it happens, SMPTE has also recommended -20 dBFS as a nominal
operation level as well!
Ahh I see - RMS where my 16.9 figure was peak ie what I would have to do
just to avoid clipping if I were really to mix equally 7 into 1.
Comments on peaks at 0dBFS noted though disney seem to push it eg.
here's what sox says about the first 5 mins of toy story 3 decoded DTS
full range.
Overall Ch1 Ch2 Ch3 Ch4 Ch5
Ch6
DC offset -0.000102 0.000041 0.000027 -0.000102 -0.000093 0.000006
0.000004
Min level -1.000000 -0.987915 -1.000000 -1.000000 -0.954895 -0.880280
-0.861542
Max level 0.999969 0.758301 0.999969 0.999969 0.961823 0.989441
0.990204
Pk lev dB 0.00 -0.11 0.00 0.00 -0.34 -0.09
-0.09
RMS lev dB -23.37 -26.48 -24.12 -17.77 -25.40 -30.79
-29.74
RMS Pk dB -1.21 -10.10 -7.36 -1.21 -3.97 -9.81
-9.98
RMS Tr dB -inf -90.01 -89.77 -89.95 -inf -87.04
-87.00
Crest factor - 20.83 16.06 7.74 17.90 34.28
30.40
Flat factor 30.62 0.00 6.76 30.65 10.63 0.00
0.00
Pk count 1.15k 2 17 6.85k 5 2
2
Bit-depth 16/16 16/16 16/16 16/16 16/16 16/16
16/16
Num samples 14.4M
Length s 300.064
Scale max 1.000000
Window s 0.050
On Sep 23, 2013, at 6:03 PM, Andy Furniss <adf.li...@gmail.com>
wrote:
Ken Landers wrote:
While -16.9 might keep you safe, a better option might be -20
dBFS. Gives some headroom in case you need it. Also, many
consumer playback devices may not handle full scale output.
Interesting, I am not a producer of anything as such, but do see
that a lot of digital music and some films push 0dBfs (though at
least the films aren't anywhere near RMS)
Do you mean that consumer DACs can't handle it properly, or that
the analogue side doesn't being driven full voltage?
Andy.
.
_______________________________________________
Sursound mailing list
Sursound@music.vt.edu
https://mail.music.vt.edu/mailman/listinfo/sursound
