bformdec
Prev | Orchestra Opcodes and Operators | Next

## bformdec

bformdec — Decodes an ambisonic B format signal

## Description

Decodes an ambisonic B format signal into loudspeaker specific signals.

## Syntax

    ao1, ao2 bformdec isetup, aw, ax, ay, az [, ar, as, at, au, av [, abk, al, am, an, ao, ap, aq]]

    ao1, ao2, ao3, ao4 bformdec isetup, aw, ax, ay, az [, ar, as, at, au, av [, abk, al, am, an, ao, ap, aq]]

    ao1, ao2, ao3, ao4, ao5 bformdec isetup, aw, ax, ay, az [, ar, as, at, au, av [, abk, al, am, an, ao, ap, aq]]

    ao1, ao2, ao3, ao4, ao5, ao6, ao7, ao8 bformdec isetup, aw, ax, ay, az [, ar, as, at, au, av [, abk, al, am, an, ao, ap, aq]]]

## Initialization

isetup –- loudspeaker setup. There are five supported setups: 1 denotes stereo setup. There must be two output cells with loudspeaker positions (azimuth angle clockwise/altitude angle) assumed to be (330/0, 30/0).

2 denotes quad setup. There must be four output cells. Loudspeaker positions assumed to be (45°/0), (135°/0), (225/0), (315/0).

3 is a 5.1 surround setup. There must be five output cells. LFE channel is not supported. Loudspeaker positions assumed to be (330/0), (30/0), (0/0), (250/0), (110/0).

4 denotes eight loudspeaker circle setup. There must be eight output cells. Loudspeaker positions assumed to be (22.5/0), (67.5/0), (112.5/0), (157.5/0), (202.5/0), (247.5/0), (292.5/0), (337.5/0).

5 means an eight loudspeaker cubic setup. There must be eight output cells. Loudspeaker positions assumed to be (45/0), (45/30), (135/0), (135/30), (225/0), (225/30), (315/0), (315/30).

## Performance

aw, ax, ay, ... -- input signal in the B format.

ao1 .. ao8 -– loudspeaker specific output signals.

## Example

    instr 1
    	; generate pink noise
    	anoise pinkish 1000

    	; two full turns
    	kalpha line 0, p3, 720
    	kbeta = 0

    	; fade ambisonic order from 2nd to 0th during second turn
    	kord0 = 1
    	kord1 linseg 1, p3 / 2, 1, p3 / 2, 0
    	kord2 linseg 1, p3 / 2, 1, p3 / 2, 0

    	; generate B format
    	aw, ax, ay, az, ar, as, at, au, av bformenc anoise, kalpha, kbeta, kord0, kord1, kord2

    	; decode B format for 8 channel circle loudspeaker setup
    	a1, a2, a3, a4, a5, a6, a7, a8 bformdec 4, aw, ax, ay, az, ar, as, at, au, av

    	; write audio out
    	out a1, a2, a3, a4, a5, a6, a7, a8
    endin

## Credits

Author: Samuel Groner
2005

Prev | Up | Next
bformenc | Home | binit