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Move AMRNB lsf2lsp() function to common code for using in future AMRWB decoder.

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Patch by Marcelo Galvăo Póvoa

Originally committed as revision 25061 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Marcelo Galvăo Póvoa 2010-09-07 20:44:41 +00:00 committed by Vitor Sessak
parent b33451eeac
commit 1d96cc0865
3 changed files with 15 additions and 16 deletions
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18
libavcodec/amrnbdec.c
View File

@ -221,20 +221,6 @@ static enum Mode unpack_bitstream(AMRContext *p, const uint8_t *buf,
/// @defgroup amr_lpc_decoding AMR pitch LPC coefficient decoding functions
/// @{
/**
* Convert an lsf vector into an lsp vector.
*
* @param lsf input lsf vector
* @param lsp output lsp vector
*/
static void lsf2lsp(const float *lsf, double *lsp)
{
int i;
for (i = 0; i < LP_FILTER_ORDER; i++)
lsp[i] = cos(2.0 * M_PI * lsf[i]);
}
/**
* Interpolate the LSF vector (used for fixed gain smoothing).
* The interpolation is done over all four subframes even in MODE_12k2.
@ -293,7 +279,7 @@ static void lsf2lsp_for_mode12k2(AMRContext *p, double lsp[LP_FILTER_ORDER],
if (update)
interpolate_lsf(p->lsf_q, lsf_q);
lsf2lsp(lsf_q, lsp);
ff_acelp_lsf2lspd(lsp, lsf_q, LP_FILTER_ORDER);
}
/**
@ -357,7 +343,7 @@ static void lsf2lsp_3(AMRContext *p)
interpolate_lsf(p->lsf_q, lsf_q);
memcpy(p->prev_lsf_r, lsf_r, LP_FILTER_ORDER * sizeof(*lsf_r));
lsf2lsp(lsf_q, p->lsp[3]);
ff_acelp_lsf2lspd(p->lsp[3], lsf_q, LP_FILTER_ORDER);
// interpolate LSP vectors at subframes 1, 2 and 3
for (i = 1; i <= 3; i++)

8
libavcodec/lsp.c
View File

@ -65,6 +65,14 @@ void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order)
lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14)
}
void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order)
{
int i;
for(i = 0; i < lp_order; i++)
lsp[i] = cos(2.0 * M_PI * lsf[i]);
}
/**
* \brief decodes polynomial coefficients from LSP
* \param f [out] decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff)

5
libavcodec/lsp.h
View File

@ -62,6 +62,11 @@ void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size);
*/
void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order);
/**
* Floating point version of ff_acelp_lsf2lsp()
*/
void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order);
/**
* \brief LSP to LP conversion (3.2.6 of G.729)
* \param[out] lp decoded LP coefficients (-0x8000 <= (3.12) < 0x8000)