Tnx a lot @ all for great info.
loudness to ITU/EBU standards at the next LAC (if the paper is
accepted).
Some filtering followed by RMS detection will provide a good
approximation to subjective loudness.
It means block schema of Automatick Gain/Volume Control is (can be)
Filter -- RMS_Calculator -- Volume_control
In exact such order ?
(- For example in FFT are used Rectangular(no window) , Hann, Hamming, Barlow ... windows. -)
What are the most common filters for ACG and "Loudness" control ?
> How to calculate RMS with hi-precision for frequencies > 10 kHz ?
> With inerpolation or so ?
Nothing special is needed for high frequencies.
Why not ?
So far i unterstand the best way for RMS calc would be SQRT of integral of power2 of sound signal function.
Real signal is not sequence of sampled rectangles, but smooth function.
Can not happen so what that rectangle inaccuracy of each sample by freq > 10KHZ ,
in end effect will accumulate big inaccuracy ?
> What is reference ( 0dB ) RMS for example for 16bit PCM signal 1024
> samples ?
Normally to do the calculations you convert first to floating point
in the range +/- 1.0. If you read a file libsndfile will do that for
you, for realtime if you use Jack all samples are already in that
format.
The reference for dB is what you make it. Normally full scale for a
sine wave is set to '0 dB' The EBU 'target' loudness is -23 dB on
that scale (which is quite low for most popular music, but probably
OK for general purpose use).
U mean that normally full amplitude sine wave is defined as 0dB RMS signal ?
Can U plz gimme some examples ?
What is RMS value dB of +/-maximum_angular signal _-_-_-_-_-
( such values - 4k times 0x8000 and 4k times 0x7FFF .... ) ?
What is RMS value dB of sine wave , peak/amplitude normalized to 0x8000-0x7FFF (or 1.0) ?
Tnx in Advance
Alfs Kurmis.
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