#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) |
Definition at line 33 of file ac3dsp.h.
| 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.
| 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. |
Referenced by encode_exponents(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_x86().
| 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.
| 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] |
Referenced by 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.
| 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 |
Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), ff_ac3dsp_init_x86(), and log2_tab().
| 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.
| 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] |
Referenced by ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_x86().
| 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.
| [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 |
Referenced by bit_alloc(), decode_audio_block(), ff_ac3dsp_init(), and ff_ac3dsp_init_arm().
| int(* AC3DSPContext::compute_mantissa_size)(uint16_t mant_cnt[6][16]) |
Calculate the number of bits needed to encode a set of mantissas.
| [in] | mant_cnt | bap counts for all blocks |
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) |
Referenced by extract_exponents(), ff_ac3dsp_init(), and ff_ac3dsp_init_arm().
| 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)].
| 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 |
Referenced by ff_ac3_float_scale_coefficients(), ff_ac3dsp_init(), ff_ac3dsp_init_arm(), and ff_ac3dsp_init_x86().
| void(* AC3DSPContext::update_bap_counts)(uint16_t mant_cnt[16], uint8_t *bap, int len) |
Update bap counts using the supplied array of bap.
| [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 |
Referenced by count_mantissa_bits_update_ch(), ff_ac3dsp_init(), and ff_ac3dsp_init_arm().
1.5.8