libavcodec/celp_math.h File Reference

#include <stdint.h>

Go to the source code of this file.

Functions
int16_t	ff_cos (uint16_t arg)
	fixed-point implementation of cosine in [0; PI) domain.
int	ff_exp2 (uint16_t power)
	fixed-point implementation of exp2(x) in [0; 1] domain.
int	ff_log2 (uint32_t value)
	Calculates log2(x).
static int	bidir_sal (int value, int offset)
	Shift value left or right depending on sign of offset parameter.
float	ff_dot_productf (const float *a, const float *b, int length)
	returns the dot product.

---

Function Documentation

static int bidir_sal	(	int	value,
		int	offset
	)			[inline, static]

Shift value left or right depending on sign of offset parameter.

Parameters:

	value	value to shift
	offset	shift offset

Returns:

value << offset, if offset>=0; value >> -offset - otherwise

Definition at line 60 of file celp_math.h.

Referenced by ff_acelp_decode_gain_code().

int16_t ff_cos

(

uint16_t

arg

)

fixed-point implementation of cosine in [0; PI) domain.

Parameters:

arg

fixed-point cosine argument, 0 <= arg < 0x4000

Returns:

value of (1<<15) * cos(arg * PI / (1<<14)), -0x8000 <= result <= 0x7fff

Definition at line 137 of file celp_math.c.

Referenced by ff_acelp_lsf2lsp().

float ff_dot_productf	(	const float *	a,
		const float *	b,
		int	length
	)

returns the dot product.

Parameters:

	a	input data array
	b	input data array
	length	number of elements

Returns:

dot product = sum of elementwise products

Definition at line 199 of file celp_math.c.

Referenced by apply_gain_ctrl(), convolve(), and decode().

int ff_exp2

(

uint16_t

power

)

fixed-point implementation of exp2(x) in [0; 1] domain.

Parameters:

power

argument to exp2, 0 <= power <= 0x7fff

Returns:

value of (1<<20) * exp2(power / (1<<15)) 0x8000c <= result <= 0xfffea

Definition at line 147 of file celp_math.c.

Referenced by ff_acelp_decode_gain_code().

int ff_log2

(

uint32_t

value

)

Calculates log2(x).

Parameters:

value

function argument, 0 < value <= 7fff ffff

Returns:

value of (1<<15) * log2(value)

Definition at line 179 of file celp_math.c.

Referenced by ff_acelp_decode_gain_code(), and ff_acelp_update_past_gain().