Commit bb937155 authored by Colin McQuillan's avatar Colin McQuillan Committed by Robert Swain
Browse files

Add a function that can apply an order 2 rational transfer function in-place.

This function will be used in the upcoming AMR-NB floating point decoder for
high-pass filtering.

Patch by Colin McQuillan ( m.niloc googlemail com )

Originally committed as revision 19649 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 735a3804
......@@ -93,3 +93,20 @@ void ff_acelp_high_pass_filter(int16_t* out, int hpf_f[2],
hpf_f[0] = tmp;
}
}
void ff_acelp_apply_order_2_transfer_function(float *buf,
const float zero_coeffs[2],
const float pole_coeffs[2],
float gain, float mem[2], int n)
{
int i;
float tmp;
for (i = 0; i < n; i++) {
tmp = gain * buf[i] - pole_coeffs[0] * mem[0] - pole_coeffs[1] * mem[1];
buf[i] = tmp + zero_coeffs[0] * mem[0] + zero_coeffs[1] * mem[1];
mem[1] = mem[0];
mem[0] = tmp;
}
}
......@@ -81,4 +81,20 @@ void ff_acelp_interpolate(int16_t* out, const int16_t* in,
void ff_acelp_high_pass_filter(int16_t* out, int hpf_f[2],
const int16_t* in, int length);
/**
* Apply an order 2 rational transfer function in-place.
*
* @param samples [in/out]
* @param zero_coeffs z^-1 and z^-2 coefficients of the numerator
* @param pole_coeffs z^-1 and z^-2 coefficients of the denominator
* @param gain scale factor for final output
* @param mem intermediate values used by filter (should be 0 initially)
* @param n number of samples
*/
void ff_acelp_apply_order_2_transfer_function(float *samples,
const float zero_coeffs[2],
const float pole_coeffs[2],
float gain,
float mem[2], int n);
#endif /* AVCODEC_ACELP_FILTERS_H */
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