DCT4 F32

Functions
void	arm_dct4_f32 (const arm_dct4_instance_f32 *S, float32_t *pState, float32_t *pInlineBuffer)
	Processing function for the floating-point DCT4/IDCT4. More...
arm_status	arm_dct4_init_f32 (arm_dct4_instance_f32 *S, arm_rfft_instance_f32 *S_RFFT, arm_cfft_radix4_instance_f32 *S_CFFT, uint16_t N, uint16_t Nby2, float32_t normalize)
	Initialization function for the floating-point DCT4/IDCT4. More...

Description

Function Documentation

arm_dct4_f32()

void arm_dct4_f32	(	const arm_dct4_instance_f32 *	S,
		float32_t *	pState,
		float32_t *	pInlineBuffer
	)

Deprecated:

Do not use this function. It is using a deprecated version of the RFFT.

Parameters

[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

Returns

none

arm_dct4_init_f32()

arm_status arm_dct4_init_f32	(	arm_dct4_instance_f32 *	S,
		arm_rfft_instance_f32 *	S_RFFT,
		arm_cfft_radix4_instance_f32 *	S_CFFT,
		uint16_t	N,
		uint16_t	Nby2,
		float32_t	normalize
	)

Deprecated:

Do not use this function. It is using a deprecated version of the RFFT.

Parameters

[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.

Returns

execution status

• ARM_MATH_SUCCESS : Operation successful
• ARM_MATH_ARGUMENT_ERROR : N is not a supported transform length

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