Equalisation frame.
This is another subjective, alignment frame. It allows the user to
predefine an equalisation curve within the audio file. There may only
be one "EQUA" frame in each tag.
| <Header of 'Equalisation', ID: "EQUA"> |
| Adjustment bits | $xx |
The 'adjustment bits' field defines the number of bits used for
representation of the adjustment. This is normally $10 (16 bits) for
MPEG 2 layer I, II and III and MPEG 2.5. This value may not be
$00.
This is followed by 2 bytes + ('adjustment bits' rounded up to the
nearest byte) for every equalisation band in the following format,
giving a frequency range of 0 - 32767Hz:
| Increment/decrement | %x (MSB of the Frequency) |
| Frequency | (lower 15 bits) |
| Adjustment | $xx (xx ...) |
The increment/decrement bit is 1 for increment and 0 for decrement.
The equalisation bands should be ordered increasingly with reference
to frequency. All frequencies don't have to be declared. The
equalisation curve in the reading software should be interpolated
between the values in this frame. Three equal adjustments for three
subsequent frequencies. A frequency should only be described once in
the frame.
For more details, please refer to the ID3 specifications:
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