[FFmpeg-cvslog] r15193 - in trunk/libavcodec: aac.c lpc.c lpc.h ra288.c
vitor
subversion
Thu Sep 4 13:03:14 CEST 2008
Author: vitor
Date: Thu Sep 4 13:03:14 2008
New Revision: 15193
Log:
Avoid duplicating compute_lpc_coefs() function in both the RA288 and AAC decoders.
Modified:
trunk/libavcodec/aac.c
trunk/libavcodec/lpc.c
trunk/libavcodec/lpc.h
trunk/libavcodec/ra288.c
Modified: trunk/libavcodec/aac.c
==============================================================================
--- trunk/libavcodec/aac.c (original)
+++ trunk/libavcodec/aac.c Thu Sep 4 13:03:14 2008
@@ -79,6 +79,7 @@
#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"
+#include "lpc.h"
#include "aac.h"
#include "aactab.h"
@@ -634,7 +635,7 @@ static int decode_tns(AACContext * ac, T
tmp2_idx = 2*coef_compress + coef_res;
for (i = 0; i < tns->order[w][filt]; i++)
- tns->coef[w][filt][i] = tns_tmp2_map[tmp2_idx][get_bits(gb, coef_len)];
+ tns->coef[w][filt][i] = -tns_tmp2_map[tmp2_idx][get_bits(gb, coef_len)];
}
}
}
@@ -1124,20 +1125,8 @@ static void apply_tns(float coef[1024],
if (order == 0)
continue;
- /* tns_decode_coef
- * FIXME: This duplicates the functionality of some double code in lpc.c.
- */
- for (m = 0; m < order; m++) {
- float tmp;
- lpc[m] = tns->coef[w][filt][m];
- for (i = 0; i < m/2; i++) {
- tmp = lpc[i];
- lpc[i] += lpc[m] * lpc[m-1-i];
- lpc[m-1-i] += lpc[m] * tmp;
- }
- if(m & 1)
- lpc[i] += lpc[m] * lpc[i];
- }
+ // tns_decode_coef
+ compute_lpc_coefs(tns->coef[w][filt], order, lpc, 0, 0, 0);
start = ics->swb_offset[FFMIN(bottom, mmm)];
end = ics->swb_offset[FFMIN( top, mmm)];
Modified: trunk/libavcodec/lpc.c
==============================================================================
--- trunk/libavcodec/lpc.c (original)
+++ trunk/libavcodec/lpc.c Thu Sep 4 13:03:14 2008
@@ -21,45 +21,10 @@
#include "libavutil/lls.h"
#include "dsputil.h"
-#include "lpc.h"
-
-
-/**
- * Levinson-Durbin recursion.
- * Produces LPC coefficients from autocorrelation data.
- */
-static void compute_lpc_coefs(const double *autoc, int max_order,
- double lpc[][MAX_LPC_ORDER], double *ref)
-{
- int i, j;
- double err = autoc[0];
- double lpc_tmp[MAX_LPC_ORDER];
-
- for(i=0; i<max_order; i++) {
- double r = -autoc[i+1];
-
- for(j=0; j<i; j++)
- r -= lpc_tmp[j] * autoc[i-j];
-
- r /= err;
- ref[i] = fabs(r);
-
- err *= 1.0 - (r * r);
- lpc_tmp[i] = r;
- for(j=0; j < i>>1; j++) {
- double tmp = lpc_tmp[j];
- lpc_tmp[j] += r * lpc_tmp[i-1-j];
- lpc_tmp[i-1-j] += r * tmp;
- }
-
- if(i & 1)
- lpc_tmp[j] += lpc_tmp[j] * r;
+#define LPC_USE_DOUBLE
+#include "lpc.h"
- for(j=0; j<=i; j++)
- lpc[i][j] = -lpc_tmp[j];
- }
-}
/**
* Quantize LPC coefficients
@@ -106,7 +71,7 @@ static void quantize_lpc_coefs(double *l
/* output quantized coefficients and level shift */
error=0;
for(i=0; i<order; i++) {
- error += lpc_in[i] * (1 << sh);
+ error -= lpc_in[i] * (1 << sh);
lpc_out[i] = av_clip(lrintf(error), -qmax, qmax);
error -= lpc_out[i];
}
@@ -147,7 +112,10 @@ int ff_lpc_calc_coefs(DSPContext *s,
if(use_lpc == 1){
s->flac_compute_autocorr(samples, blocksize, max_order, autoc);
- compute_lpc_coefs(autoc, max_order, lpc, ref);
+ compute_lpc_coefs(autoc, max_order, &lpc[0][0], MAX_LPC_ORDER, 0, 1);
+
+ for(i=0; i<max_order; i++)
+ ref[i] = fabs(lpc[i][i]);
}else{
LLSModel m[2];
double var[MAX_LPC_ORDER+1], weight;
@@ -179,7 +147,7 @@ int ff_lpc_calc_coefs(DSPContext *s,
for(i=0; i<max_order; i++){
for(j=0; j<max_order; j++)
- lpc[i][j]= m[(pass-1)&1].coeff[i][j];
+ lpc[i][j]=-m[(pass-1)&1].coeff[i][j];
ref[i]= sqrt(m[(pass-1)&1].variance[i] / weight) * (blocksize - max_order) / 4000;
}
for(i=max_order-1; i>0; i--)
Modified: trunk/libavcodec/lpc.h
==============================================================================
--- trunk/libavcodec/lpc.h (original)
+++ trunk/libavcodec/lpc.h Thu Sep 4 13:03:14 2008
@@ -45,4 +45,58 @@ int ff_lpc_calc_coefs(DSPContext *s,
int32_t coefs[][MAX_LPC_ORDER], int *shift, int use_lpc,
int omethod, int max_shift, int zero_shift);
+#ifdef LPC_USE_DOUBLE
+#define LPC_type double
+#else
+#define LPC_type float
+#endif
+
+/**
+ * Levinson-Durbin recursion.
+ * Produces LPC coefficients from autocorrelation data.
+ */
+static inline int compute_lpc_coefs(const LPC_type *autoc, int max_order,
+ LPC_type *lpc, int lpc_stride, int fail,
+ int normalize)
+{
+ int i, j;
+ LPC_type err;
+ LPC_type *lpc_last = lpc;
+
+ if (normalize)
+ err = *autoc++;
+
+ if (fail && (autoc[max_order - 1] == 0 || err <= 0))
+ return -1;
+
+ for(i=0; i<max_order; i++) {
+ LPC_type r = -autoc[i];
+
+ if (normalize) {
+ for(j=0; j<i; j++)
+ r -= lpc_last[j] * autoc[i-j-1];
+
+ r /= err;
+ err *= 1.0 - (r * r);
+ }
+
+ lpc[i] = r;
+
+ for(j=0; j < (i+1)>>1; j++) {
+ LPC_type f = lpc_last[ j];
+ LPC_type b = lpc_last[i-1-j];
+ lpc[ j] = f + r * b;
+ lpc[i-1-j] = b + r * f;
+ }
+
+ if (fail && err < 0)
+ return -1;
+
+ lpc_last = lpc;
+ lpc += lpc_stride;
+ }
+
+ return 0;
+}
+
#endif /* AVCODEC_LPC_H */
Modified: trunk/libavcodec/ra288.c
==============================================================================
--- trunk/libavcodec/ra288.c (original)
+++ trunk/libavcodec/ra288.c Thu Sep 4 13:03:14 2008
@@ -23,6 +23,7 @@
#define ALT_BITSTREAM_READER_LE
#include "bitstream.h"
#include "ra288.h"
+#include "lpc.h"
typedef struct {
float sp_lpc[36]; ///< LPC coefficients for speech data (spec: A)
@@ -113,44 +114,6 @@ static void decode(RA288Context *ractx,
block[i] = av_clipf(block[i] + buffer[i], -4095, 4095);
}
-/**
- * Converts autocorrelation coefficients to LPC coefficients using the
- * Levinson-Durbin algorithm. See blocks 37 and 50 of the G.728 specification.
- *
- * @return 0 if success, -1 if fail
- */
-static int eval_lpc_coeffs(const float *in, float *tgt, int n)
-{
- int i, j;
- double f0, f1, f2;
-
- if (in[n] == 0)
- return -1;
-
- if ((f0 = *in) <= 0)
- return -1;
-
- in--; // To avoid a -1 subtraction in the inner loop
-
- for (i=1; i <= n; i++) {
- f1 = in[i+1];
-
- for (j=0; j < i - 1; j++)
- f1 += in[i-j]*tgt[j];
-
- tgt[i-1] = f2 = -f1/f0;
- for (j=0; j < i >> 1; j++) {
- float temp = tgt[j] + tgt[i-j-2]*f2;
- tgt[i-j-2] += tgt[j]*f2;
- tgt[j] = temp;
- }
- if ((f0 += f1*f2) < 0)
- return -1;
- }
-
- return 0;
-}
-
static void convolve(float *tgt, const float *src, int len, int n)
{
for (; n >= 0; n--)
@@ -210,13 +173,13 @@ static void backward_filter(RA288Context
do_hybrid_window(36, 40, 35, ractx->sp_block+1, temp1, ractx->sp_hist,
ractx->sp_rec, syn_window);
- if (!eval_lpc_coeffs(temp1, ractx->sp_lpc, 36))
+ if (!compute_lpc_coefs(temp1, 36, ractx->sp_lpc, 0, 1, 1))
colmult(ractx->sp_lpc, ractx->sp_lpc, syn_bw_tab, 36);
do_hybrid_window(10, 8, 20, ractx->gain_block+2, temp2, ractx->gain_hist,
ractx->gain_rec, gain_window);
- if (!eval_lpc_coeffs(temp2, ractx->gain_lpc, 10))
+ if (!compute_lpc_coefs(temp2, 10, ractx->gain_lpc, 0, 1, 1))
colmult(ractx->gain_lpc, ractx->gain_lpc, gain_bw_tab, 10);
}
More information about the ffmpeg-cvslog
mailing list