g722.c File Reference

G.722 ADPCM audio codec. More...

#include "mathops.h"
#include "g722.h"

Macros
#define	ACCUM(k, x, d)

Functions
void	ff_g722_update_low_predictor (struct G722Band *band, const int ilow)
void	ff_g722_update_high_predictor (struct G722Band *band, const int dhigh, const int ihigh)

Variables
const int16_t	ff_g722_high_inv_quant [4] = { -926, -202, 926, 202 }
const int16_t	ff_g722_low_inv_quant4 [16]
const int16_t	ff_g722_low_inv_quant6 [64]

Detailed Description

G.722 ADPCM audio codec.

This G.722 decoder is a bit-exact implementation of the ITU G.722 specification for all three specified bitrates - 64000bps, 56000bps and 48000bps. It passes the ITU tests.

Note

For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits respectively of each byte are ignored.

Macro Definition Documentation

ACCUM

#define ACCUM	(		k,
			x,
			d
	)

Value:

do { \
            int tmp = x; \
            band->zero_mem[k] = ((band->zero_mem[k] * 255) >> 8) + \
               d*((band->diff_mem[k]^cur_diff) < 0 ? -128 : 128); \
            band->diff_mem[k] = tmp; \
            s_zero += (tmp * band->zero_mem[k]) >> 15; \
        } while (0)

Variable Documentation

ff_g722_low_inv_quant4

const int16_t ff_g722_low_inv_quant4[16]

Initial value:

= {
       0, -2557, -1612, -1121,  -786,  -530,  -323,  -150,
    2557,  1612,  1121,   786,   530,   323,   150,     0
}

ff_g722_low_inv_quant6

const int16_t ff_g722_low_inv_quant6[64]

Initial value:

= {
     -17,   -17,   -17,   -17, -3101, -2738, -2376, -2088,
   -1873, -1689, -1535, -1399, -1279, -1170, -1072,  -982,
    -899,  -822,  -750,  -682,  -618,  -558,  -501,  -447,
    -396,  -347,  -300,  -254,  -211,  -170,  -130,   -91,
    3101,  2738,  2376,  2088,  1873,  1689,  1535,  1399,
    1279,  1170,  1072,   982,   899,   822,   750,   682,
     618,   558,   501,   447,   396,   347,   300,   254,
     211,   170,   130,    91,    54,    17,   -54,   -17
}