#define BIAS 0x84       /* define the add-in bias for 16 bit samples */
#define CLIP 32635

#define FRAMESIZE 160
#define LPC_FILTORDER 10

typedef struct {
      unsigned short period;
      unsigned char gain;
      char k[LPC_FILTORDER];
      char pad;
} lpcparams_t;

/*
 * we can't use 'sizeof(lpcparams_t)' because some compilers
 * add random padding so define size of record that goes over net.
 */
#define LPCRECSIZE 14

typedef struct {
      double Oldper, OldG, Oldk[LPC_FILTORDER + 1], bp[LPC_FILTORDER + 1];
      int pitchctr;
} lpcstate_t;

void lpc_init(lpcstate_t* state);
void lpc_analyze(short *buf, lpcparams_t *params);
int lpc_synthesize(short *buf, lpcparams_t *params, lpcstate_t* state, double speedup);

#define MAXWINDOW 1000  /* Max analysis window length */
#define FS        8000.0      /* Sampling rate */

#define DOWN            5     /* Decimation for pitch analyzer */
#define PITCHORDER      4     /* Model order for pitch analyzer */
#define FC        600.0 /* Pitch analyzer filter cutoff */
#define MINPIT          50.0  /* Minimum pitch */
#define MAXPIT          300.0 /* Maximum pitch */

#define MINPER          (int)(FS/(DOWN*MAXPIT)+.5)    /* Minimum period */
#define MAXPER          (int)(FS/(DOWN*MINPIT)+.5)    /* Maximum period */

#define WSCALE          1.5863      /* Energy loss due to windowing */

#define BUFLEN          ((FRAMESIZE * 3) / 2)

/* This reduces the output gain so we are less likely to clip. */
#define GAIN_REDUCTION 0.8