NMSIS-DSP  Version 1.3.1
NMSIS DSP Software Library

Functions

RISCV_DSP_ATTRIBUTE void riscv_dct4_f32 (const riscv_dct4_instance_f32 *S, float32_t *pState, float32_t *pInlineBuffer)
 Processing function for the floating-point DCT4/IDCT4. More...
 
RISCV_DSP_ATTRIBUTE riscv_status riscv_dct4_init_f32 (riscv_dct4_instance_f32 *S, riscv_rfft_instance_f32 *S_RFFT, riscv_cfft_radix4_instance_f32 *S_CFFT, uint16_t N, uint16_t Nby2, float32_t normalize)
 Initialization function for the floating-point DCT4/IDCT4. More...
 

Detailed Description

Function Documentation

◆ riscv_dct4_f32()

RISCV_DSP_ATTRIBUTE void riscv_dct4_f32 ( const riscv_dct4_instance_f32 S,
float32_t pState,
float32_t pInlineBuffer 
)

Processing function for the floating-point DCT4/IDCT4.

Deprecated:
Do not use this function. It is using a deprecated version of the RFFT.
Parameters
[in]Spoints to an instance of the floating-point DCT4/IDCT4 structure
[in]pStatepoints to state buffer
[in,out]pInlineBufferpoints to the in-place input and output buffer

◆ riscv_dct4_init_f32()

RISCV_DSP_ATTRIBUTE riscv_status riscv_dct4_init_f32 ( riscv_dct4_instance_f32 S,
riscv_rfft_instance_f32 S_RFFT,
riscv_cfft_radix4_instance_f32 S_CFFT,
uint16_t  N,
uint16_t  Nby2,
float32_t  normalize 
)

Initialization function for the floating-point DCT4/IDCT4.

Deprecated:
Do not use this function. It is using a deprecated version of the RFFT.
Parameters
[in,out]Spoints to an instance of floating-point DCT4/IDCT4 structure
[in]S_RFFTpoints to an instance of floating-point RFFT/RIFFT structure
[in]S_CFFTpoints to an instance of floating-point CFFT/CIFFT structure
[in]Nlength of the DCT4
[in]Nby2half of the length of the DCT4
[in]normalizenormalizing factor.
Returns
execution status
Normalizing factor
The normalizing factor is sqrt(2/N), which depends on the size of transform N. Floating-point normalizing factors are mentioned in the table below for different DCT sizes:
DCT Size Normalizing factor value
2048 0.03125
512 0.0625
128 0.125