btstack/test/sbc/sbc_synthesis_v1.py

#!/usr/bin/env python
import numpy as np
import wave
import struct
import sys
import time
from sbc import *

matrix_R = np.zeros(shape = (16,8))
matrix_C2 = np.zeros(shape = (8,8))
matrix_N = np.zeros(shape = (16,16))

def sbc_init_synthesis_v1(M):
    global matrix_R, matrix_C2, matrix_N
    if M == 4:
        print("SBC V1 init failed, 4-subband version not implemented yet")
    M2 = M << 1
    Mh = M >> 1
    
    matrix_R = np.zeros(shape = (M2,M))
    matrix_C2 = np.zeros(shape = (M,M))
    matrix_N = np.zeros(shape = (M2,M2))

    R_c1 = 12 
    
    for k in range(Mh):
        matrix_R[k][k+Mh] = 1

    for k in range(Mh+1,M2):
        matrix_R[k][abs(R_c1-k)] = -1

    for k in range(M):
        for i in range(M):
            matrix_C2[k][i] = np.cos((i+0.5)*k*np.pi/M)
    
    matrix_N = np.dot(matrix_R, matrix_C2)

def sbc_frame_synthesis_v1_4subbands(frame, ch, blk):
    print "sbc_frame_synthesis_v1_4subbands(frame, ch, blk) not implemented yet"
    exit(1)

def sbc_frame_synthesis_v1_8subbands(frame, ch, blk):
    print "sbc_frame_synthesis_v1_8subbands(frame, ch, blk) not implemented yet"
    exit(1)

def matrix_R():
    global matrix_R
    return matrix_R

def matrix_C2():
    global matrix_C2
    return matrix_C2

def matrix_N():
    global matrix_N
    return matrix_N

def R(k,i):
    global matrix_R
    return matrix_R[k][i]

def C2(k,i):
    global matrix_C2
    return matrix_C2[k][i]