4.12. Equalisation (2)
This is another subjective, alignment frame. It allows the user to
predefine an equalisation curve within the audio file. There may be
more than one "EQU2" frame in each tag, but only one with the same
identification string.
<Header of 'Equalisation (2)', ID: "EQU2">
Interpolation method $xx
Identification <text string> $00
The 'interpolation method' describes which method is preferred when
an interpolation between the adjustment point that follows. The
following methods are currently defined:
$00 Band
No interpolation is made. A jump from one adjustment level to
another occurs in the middle between two adjustment points.
$01 Linear
Interpolation between adjustment points is linear.
The 'identification' string is used to identify the situation and/or
device where this adjustment should apply. The following is then
repeated for every adjustment point
Frequency $xx xx
Volume adjustment $xx xx
The frequency is stored in units of 1/2 Hz, giving it a range from 0
to 32767 Hz.
The volume adjustment is encoded as a fixed point decibel value, 16
bit signed integer representing (adjustment*512), giving +/- 64 dB
with a precision of 0.001953125 dB. E.g. +2 dB is stored as $04 00
and -2 dB is $FC 00.
Adjustment points should be ordered by frequency and one frequency
should only be described once in the frame.
@author Eric Farng
@version $Revision: 1.5 $