DCT Type IV Tables

const float32_t Weights_128[256]
const float32_t cos_factors_128[128]
const float32_t Weights_512[1024]
const float32_t cos_factors_512[512]
const float32_t Weights_2048[4096]
const float32_t cos_factors_2048[2048]
const q31_t WeightsQ31_128[256]
const q31_t cos_factorsQ31_128[128]
const q31_t WeightsQ31_512[1024]
const q31_t cos_factorsQ31_512[512]
const q31_t WeightsQ31_2048[4096]
const q31_t cos_factorsQ31_2048[2048]
const q15_t __ALIGNED(4)
group DCT4_IDCT4_Table

Functions

const q15_t __ALIGNED(4)

Weights Table.

Q15 table for reciprocal.

end of DCT4_IDCT4_Table group

Weights tables are generated using the formula :

C command to generate the table

where N is the Number of weights to be calculated and c is pi/(2*N)

Converted the output to q15 format by multiplying with 2^31 and saturated if required.

In the tables below the real and imaginary values are placed alternatively, hence the array length is 2*N.

cosFactor tables are generated using the formula :

C command to generate the table

where N is the number of factors to generate and c is pi/(2*N)

Then converted to q15 format by multiplying with 2^31 and saturated if required.

Generation of real_CoefB array:

n = 4096

Convert to fixed point Q15 format round(pBTable[i] * pow(2, 15))

Variables

const float32_t Weights_128[256]

Weights Table.

Weights tables are generated using the formula :

C command to generate the table

where N is the Number of weights to be calculated and c is pi/(2*N)

In the tables below the real and imaginary values are placed alternatively, hence the array length is 2*N.

cosFactor tables are generated using the formula :

C command to generate the table

where N is the number of factors to generate and c is pi/(2*N)

const float32_t cos_factors_128[128]
const float32_t Weights_512[1024]
const float32_t cos_factors_512[512]
const float32_t Weights_2048[4096]
const float32_t cos_factors_2048[2048]
const q31_t WeightsQ31_128[256]

Weights tables are generated using the formula :

C command to generate the table

where N is the Number of weights to be calculated and c is pi/(2*N)

Convert the output to q31 format by multiplying with 2^31 and saturated if required.

In the tables below the real and imaginary values are placed alternatively, hence the array length is 2*N.

cosFactor tables are generated using the formula :

C command to generate the table

where N is the number of factors to generate and c is pi/(2*N)

Then converted to q31 format by multiplying with 2^31 and saturated if required.

const q31_t cos_factorsQ31_128[128]
const q31_t WeightsQ31_512[1024]
const q31_t cos_factorsQ31_512[512]
const q31_t WeightsQ31_2048[4096]
const q31_t cos_factorsQ31_2048[2048]