Functions | |
arm_status | arm_dct4_init_q15 (arm_dct4_instance_q15 *S, arm_rfft_instance_q15 *S_RFFT, arm_cfft_radix4_instance_q15 *S_CFFT, uint16_t N, uint16_t Nby2, q15_t normalize) |
Initialization function for the Q15 DCT4/IDCT4. | |
void | arm_dct4_q15 (const arm_dct4_instance_q15 *S, q15_t *pState, q15_t *pInlineBuffer) |
Processing function for the Q15 DCT4/IDCT4. | |
arm_status arm_dct4_init_q15 | ( | arm_dct4_instance_q15 * | S, |
arm_rfft_instance_q15 * | S_RFFT, | ||
arm_cfft_radix4_instance_q15 * | S_CFFT, | ||
uint16_t | N, | ||
uint16_t | Nby2, | ||
q15_t | normalize | ||
) |
Initialization function for the Q15 DCT4/IDCT4.
[in,out] | S | points to an instance of Q15 DCT4/IDCT4 structure |
[in] | S_RFFT | points to an instance of Q15 RFFT/RIFFT structure |
[in] | S_CFFT | points to an instance of Q15 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
. Normalizing factors in 1.15 format are mentioned in the table below for different DCT sizes:DCT Size | Normalizing factor value (hexadecimal) |
---|---|
2048 | 0x400 |
512 | 0x800 |
128 | 0x1000 |
void arm_dct4_q15 | ( | const arm_dct4_instance_q15 * | S, |
q15_t * | pState, | ||
q15_t * | pInlineBuffer | ||
) |
Processing function for the Q15 DCT4/IDCT4.
[in] | S | points to an instance of the Q15 DCT4 structure. |
[in] | pState | points to state buffer. |
[in,out] | pInlineBuffer | points to the in-place input and output buffer. |
DCT Size | Input format | Output format | Number of bits to upscale |
---|---|---|---|
2048 | 1.15 | 11.5 | 10 |
512 | 1.15 | 9.7 | 8 |
128 | 1.15 | 7.9 | 6 |