videolan
/
ffmpeg
mirror of https://git.videolan.org/git/ffmpeg.git
1
Fork 0
Code Releases Activity

Part 2 of 2 of Kenan Gillet's 'make ff_qcelp_lspf2lpc 

more general' changeset. This one relocates the QCELP
especific code to the qcelpdec.* files.

Originally committed as revision 17800 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reynaldo H. Verdejo Pinochet 2009-03-04 01:33:56 +00:00
parent 77bd18e117
commit 87574416f7
3 changed files with 45 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
libavcodec/qcelp_lsp.c
View File

@ -29,15 +29,6 @@
#include "libavutil/mathematics.h"
/**
* initial coefficient to perform bandwidth expansion on LPC
*
* @note: 0.9883 looks like an approximation of 253/256.
*
* TIA/EIA/IS-733 2.4.3.3.6 6
*/
#define QCELP_BANDWITH_EXPANSION_COEFF 0.9883
/**
* Computes the Pa / (1 + z(-1)) or Qa / (1 - z(-1)) coefficients
* needed for LSP to LPC conversion.
@ -84,37 +75,7 @@ void ff_celp_lspf2lpc(const double *lspf, float *lpc)
double paf = pa[i+1] + pa[i];
double qaf = qa[i+1] - qa[i];
lpc[i ] = 0.5 * (paf+qaf);
lpc[9-i] = 0.5 * (paf-qaf);
}
}
/**
* Reconstructs LPC coefficients from the line spectral pair frequencies
* and performs bandwidth expansion.
*
* @param lspf line spectral pair frequencies
* @param lpc linear predictive coding coefficients
*
* @note: bandwith_expansion_coeff could be precalculated into a table
* but it seems to be slower on x86
*
* TIA/EIA/IS-733 2.4.3.3.5
*/
void ff_qcelp_lspf2lpc(const float *lspf, float *lpc)
{
double lsf[10];
double bandwith_expansion_coeff = QCELP_BANDWITH_EXPANSION_COEFF;
int i;
for (i=0; i<10; i++)
lsf[i] = cos(M_PI * lspf[i]);
ff_celp_lspf2lpc(lsf, lpc);
for (i=0; i<10; i++)
{
lpc[i] *= bandwith_expansion_coeff;
bandwith_expansion_coeff *= QCELP_BANDWITH_EXPANSION_COEFF;
lpc[i ] = 0.5*(paf+qaf);
lpc[9-i] = 0.5*(paf-qaf);
}
}

9
libavcodec/qcelpdata.h
View File

@ -550,4 +550,13 @@ static const double qcelp_rnd_fir_coefs[11] = {
*/
#define QCELP_LSP_OCTAVE_PREDICTOR 29.0/32
/**
* initial coefficient to perform bandwidth expansion on LPC
*
* @note: 0.9883 looks like an approximation of 253/256.
*
* TIA/EIA/IS-733 2.4.3.3.6 6
*/
#define QCELP_BANDWITH_EXPANSION_COEFF 0.9883
#endif /* AVCODEC_QCELPDATA_H */

38
libavcodec/qcelpdec.c
View File

@ -79,7 +79,7 @@ typedef struct
*
* TIA/EIA/IS-733 2.4.3.3.5
*/
void ff_qcelp_lspf2lpc(const float *lspf, float *lpc);
void ff_celp_lspf2lpc(const double *lspf, float *lpc);
static void weighted_vector_sumf(float *out, const float *in_a,
const float *in_b, float weight_coeff_a,
@ -584,6 +584,36 @@ static void apply_pitch_filters(QCELPContext *q, float *cdn_vector)
}
}
/**
* Reconstructs LPC coefficients from the line spectral pair frequencies
* and performs bandwidth expansion.
*
* @param lspf line spectral pair frequencies
* @param lpc linear predictive coding coefficients
*
* @note: bandwith_expansion_coeff could be precalculated into a table
* but it seems to be slower on x86
*
* TIA/EIA/IS-733 2.4.3.3.5
*/
void lspf2lpc(const float *lspf, float *lpc)
{
double lsf[10];
double bandwith_expansion_coeff = QCELP_BANDWITH_EXPANSION_COEFF;
int i;
for (i=0; i<10; i++)
lsf[i] = cos(M_PI * lspf[i]);
ff_celp_lspf2lpc(lsf, lpc);
for (i=0; i<10; i++)
{
lpc[i] *= bandwith_expansion_coeff;
bandwith_expansion_coeff *= QCELP_BANDWITH_EXPANSION_COEFF;
}
}
/**
* Interpolates LSP frequencies and computes LPC coefficients
* for a given bitrate & pitch subframe.
@ -612,12 +642,12 @@ void interpolate_lpc(QCELPContext *q, const float *curr_lspf, float *lpc,
{
weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf,
weight, 1.0 - weight, 10);
ff_qcelp_lspf2lpc(interpolated_lspf, lpc);
lspf2lpc(interpolated_lspf, lpc);
}else if(q->bitrate >= RATE_QUARTER ||
(q->bitrate == I_F_Q && !subframe_num))
ff_qcelp_lspf2lpc(curr_lspf, lpc);
lspf2lpc(curr_lspf, lpc);
else if(q->bitrate == SILENCE && !subframe_num)
ff_qcelp_lspf2lpc(q->prev_lspf, lpc);
lspf2lpc(q->prev_lspf, lpc);
}
static qcelp_packet_rate buf_size2bitrate(const int buf_size)