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Implement ff_scale_vector_to_given_sum_of_squares()

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to aid generic gain control routines. Changes
for qcelp are included. Patch Collin McQuillan.

Originally committed as revision 20450 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reynaldo H. Verdejo Pinochet 2009-11-04 19:29:29 +00:00
parent 223217746c
commit 0c50f8e6cc
3 changed files with 36 additions and 33 deletions
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12
libavcodec/acelp_vectors.c
View File

@ -22,6 +22,7 @@
#include <inttypes.h> #include <inttypes.h>
#include "avcodec.h" #include "avcodec.h"
#include "celp_math.h"
#include "acelp_vectors.h" #include "acelp_vectors.h"
#include "celp_math.h" #include "celp_math.h"
@ -177,3 +178,14 @@ void ff_adaptative_gain_control(float *buf_out, float speech_energ,
*gain_mem = mem; *gain_mem = mem;
} }
void ff_scale_vector_to_given_sum_of_squares(float *out, const float *in,
float sum_of_squares, const int n)
{
int i;
float scalefactor = ff_dot_productf(in, in, n);
if (scalefactor)
scalefactor = sqrt(sum_of_squares / scalefactor);
for (i = 0; i < n; i++)
out[i] = in[i] * scalefactor;
}

18
libavcodec/acelp_vectors.h
View File

@ -176,4 +176,22 @@ void ff_weighted_vector_sumf(float *out, const float *in_a, const float *in_b,
void ff_adaptative_gain_control(float *buf_out, float speech_energ, void ff_adaptative_gain_control(float *buf_out, float speech_energ,
int size, float alpha, float *gain_mem); int size, float alpha, float *gain_mem);
/**
* Set the sum of squares of a signal by scaling
*
* @param out output samples
* @param in input samples
* @param sum_of_squares new sum of squares
* @param n number of samples
*
* @note If the input is zero (or its energy underflows), the output is zero.
* This is the behavior of AGC in the AMR reference decoder. The QCELP
* reference decoder seems to have undefined behavior.
*
* TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6
* 3GPP TS 26.090 6.1 (6)
*/
void ff_scale_vector_to_given_sum_of_squares(float *out, const float *in,
float sum_of_squares, const int n);
#endif /* AVCODEC_ACELP_VECTORS_H */ #endif /* AVCODEC_ACELP_VECTORS_H */

39
libavcodec/qcelpdec.c
View File

@ -405,31 +405,6 @@ static void compute_svector(QCELPContext *q, const float *gain,
} }
} }
/**
* Compute the gain control
*
* @param v_in gain-controlled vector
* @param v_ref vector to control gain of
*
* @return gain control
*
* FIXME: If v_ref is a zero vector, it energy is zero
* and the behavior of the gain control is
* undefined in the specs.
*
* TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6
*/
static float compute_gain_ctrl(const float *v_ref, const float *v_in, const int len)
{
float scalefactor = ff_dot_productf(v_in, v_in, len);
if(scalefactor)
scalefactor = sqrt(ff_dot_productf(v_ref, v_ref, len) / scalefactor);
else
av_log_missing_feature(NULL, "Zero energy for gain control", 1);
return scalefactor;
}
/** /**
* Apply generic gain control. * Apply generic gain control.
* *
@ -442,15 +417,13 @@ static float compute_gain_ctrl(const float *v_ref, const float *v_in, const int
static void apply_gain_ctrl(float *v_out, const float *v_ref, static void apply_gain_ctrl(float *v_out, const float *v_ref,
const float *v_in) const float *v_in)
{ {
int i, j, len; int i;
float scalefactor;
for(i=0, j=0; i<4; i++) for (i = 0; i < 160; i += 40)
{ ff_scale_vector_to_given_sum_of_squares(v_out + i, v_in + i,
scalefactor = compute_gain_ctrl(v_ref + j, v_in + j, 40); ff_dot_productf(v_ref + i,
for(len=j+40; j<len; j++) v_ref + i, 40),
v_out[j] = scalefactor * v_in[j]; 40);
}
} }
/** /**