#include <ac3dsp.h>

Data Fields
void(*	ac3_exponent_min )(uint8_t *exp, int num_reuse_blocks, int nb_coefs)
	Set each encoded exponent in a block to the minimum of itself and the exponents in the same frequency bin of up to 5 following blocks.

int(*	ac3_max_msb_abs_int16 )(const int16_t *src, int len)
	Calculate the maximum MSB of the absolute value of each element in an array of int16_t.

void(*	ac3_lshift_int16 )(int16_t *src, unsigned int len, unsigned int shift)
	Left-shift each value in an array of int16_t by a specified amount.

void(*	ac3_rshift_int32 )(int32_t *src, unsigned int len, unsigned int shift)
	Right-shift each value in an array of int32_t by a specified amount.

void(*	float_to_fixed24 )(int32_t dst, const float src, unsigned int len)
	Convert an array of float in range [-1.0,1.0] to int32_t with range [-(1<<24),(1<<24)].

void(*	bit_alloc_calc_bap )(int16_t mask, int16_t psd, int start, int end, int snr_offset, int floor, const uint8_t bap_tab, uint8_t bap)
	Calculate bit allocation pointers.

void(*	update_bap_counts )(uint16_t mant_cnt[16], uint8_t *bap, int len)
	Update bap counts using the supplied array of bap.

int(*	compute_mantissa_size )(uint16_t mant_cnt[6][16])
	Calculate the number of bits needed to encode a set of mantissas.

void(*	extract_exponents )(uint8_t exp, int32_t coef, int nb_coefs)

void(*	sum_square_butterfly_int32 )(int64_t sum[4], const int32_t coef0, const int32_t coef1, int len)

void(*	sum_square_butterfly_float )(float sum[4], const float coef0, const float coef1, int len)

void(*	downmix )(float *samples, float(matrix)[2], int out_ch, int in_ch, int len)

Detailed Description

Definition at line 33 of file ac3dsp.h.

Field Documentation

void(* AC3DSPContext::ac3_exponent_min)(uint8_t *exp, int num_reuse_blocks, int nb_coefs)

Set each encoded exponent in a block to the minimum of itself and the exponents in the same frequency bin of up to 5 following blocks.

Parameters

exp	pointer to the start of the current block of exponents. constraints: align 16
num_reuse_blocks	number of blocks that will reuse exponents from the current block. constraints: range 0 to 5
nb_coefs	number of frequency coefficients.

Definition at line 43 of file ac3dsp.h.

Referenced by encode_exponents(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_x86().

int(* AC3DSPContext::ac3_max_msb_abs_int16)(const int16_t *src, int len)

Calculate the maximum MSB of the absolute value of each element in an array of int16_t.

Parameters

src	input array constraints: align 16. values must be in range [-32767,32767]
len	number of values in the array constraints: multiple of 16 greater than 0

Returns: a value with the same MSB as max(abs(src[]))

Definition at line 54 of file ac3dsp.h.

Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), ff_ac3dsp_init_x86(), and normalize_samples().

void(* AC3DSPContext::ac3_lshift_int16)(int16_t *src, unsigned int len, unsigned int shift)

Left-shift each value in an array of int16_t by a specified amount.

Parameters

src	input array constraints: align 16
len	number of values in the array constraints: multiple of 32 greater than 0
shift	left shift amount constraints: range [0,15]

Definition at line 65 of file ac3dsp.h.

Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), ff_ac3dsp_init_x86(), and normalize_samples().

void(* AC3DSPContext::ac3_rshift_int32)(int32_t *src, unsigned int len, unsigned int shift)

Right-shift each value in an array of int32_t by a specified amount.

Parameters

src	input array constraints: align 16
len	number of values in the array constraints: multiple of 16 greater than 0
shift	right shift amount constraints: range [0,31]

Definition at line 76 of file ac3dsp.h.

Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), ff_ac3dsp_init_x86(), and scale_coefficients().

void(* AC3DSPContext::float_to_fixed24)(int32_t *dst, const float *src, unsigned int len)

Convert an array of float in range [-1.0,1.0] to int32_t with range [-(1<<24),(1<<24)].

Parameters

dst	destination array of int32_t. constraints: 16-byte aligned
src	source array of float. constraints: 16-byte aligned
len	number of elements to convert. constraints: multiple of 32 greater than zero

Definition at line 89 of file ac3dsp.h.

Referenced by apply_channel_coupling(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), ff_ac3dsp_init_mips(), ff_ac3dsp_init_x86(), and scale_coefficients().

void(* AC3DSPContext::bit_alloc_calc_bap)(int16_t *mask, int16_t *psd, int start, int end, int snr_offset, int floor, const uint8_t *bap_tab, uint8_t *bap)

Calculate bit allocation pointers.

The SNR is the difference between the masking curve and the signal. AC-3 uses this value for each frequency bin to allocate bits. The snroffset parameter is a global adjustment to the SNR for all bins.

Parameters

[in]	mask	masking curve
[in]	psd	signal power for each frequency bin
[in]	start	starting bin location
[in]	end	ending bin location
[in]	snr_offset	SNR adjustment
[in]	floor	noise floor
[in]	bap_tab	look-up table for bit allocation pointers
[out]	bap	bit allocation pointers

Definition at line 106 of file ac3dsp.h.

Referenced by bit_alloc(), decode_audio_block(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_mips().

void(* AC3DSPContext::update_bap_counts)(uint16_t mant_cnt[16], uint8_t *bap, int len)

Update bap counts using the supplied array of bap.

Parameters

[out]	mant_cnt	bap counts for 1 block
[in]	bap	array of bap, pointing to start coef bin
[in]	len	number of elements to process

Definition at line 117 of file ac3dsp.h.

Referenced by count_mantissa_bits_update_ch(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_mips().

int(* AC3DSPContext::compute_mantissa_size)(uint16_t mant_cnt[6][16])

Calculate the number of bits needed to encode a set of mantissas.

Parameters

[in] mant_cnt bap counts for all blocks

Returns: mantissa bit count

Definition at line 125 of file ac3dsp.h.

Referenced by count_mantissa_bits(), ff_ac3dsp_init(), and ff_ac3dsp_init_x86().

void(* AC3DSPContext::extract_exponents)(uint8_t *exp, int32_t *coef, int nb_coefs)

Definition at line 127 of file ac3dsp.h.

Referenced by apply_channel_coupling(), extract_exponents(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_x86().

void(* AC3DSPContext::sum_square_butterfly_int32)(int64_t sum[4], const int32_t *coef0, const int32_t *coef1, int len)

Definition at line 129 of file ac3dsp.h.

Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and sum_square_butterfly().

void(* AC3DSPContext::sum_square_butterfly_float)(float sum[4], const float *coef0, const float *coef1, int len)

Definition at line 132 of file ac3dsp.h.

Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and sum_square_butterfly().

void(* AC3DSPContext::downmix)(float **samples, float(*matrix)[2], int out_ch, int in_ch, int len)

Definition at line 135 of file ac3dsp.h.

Referenced by decode_audio_block(), ff_ac3dsp_init(), ff_ac3dsp_init_mips(), and ff_ac3dsp_init_x86().

The documentation for this struct was generated from the following file:

libavcodec/ac3dsp.h

Data Fields

Detailed Description

Field Documentation