NMSIS-DSP
Version 1.3.1
NMSIS DSP Software Library
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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... | |
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.
[in] | S | points to an instance of the floating-point DCT4/IDCT4 structure |
[in] | pState | points to state buffer |
[in,out] | pInlineBuffer | points to the in-place input and output buffer |
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.
[in,out] | S | points to an instance of floating-point DCT4/IDCT4 structure |
[in] | S_RFFT | points to an instance of floating-point RFFT/RIFFT structure |
[in] | S_CFFT | points to an instance of floating-point CFFT/CIFFT structure |
[in] | N | length of the DCT4 |
[in] | Nby2 | half of the length of the DCT4 |
[in] | normalize | normalizing factor. |
N
is not a supported transform lengthsqrt(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 |