silence gcc warning: ‘n_bands’ may be used uninitialized

[ffmpeg] / libavcodec / lpc.c

diff --git a/libavcodec/lpc.c b/libavcodec/lpc.c
index a8971d3c84726ff0886acd51f9395433eae60658..dd145ca8756a0e07987f54be4f5d85afe4217be3 100644 (file)
--- a/libavcodec/lpc.c
+++ b/libavcodec/lpc.c
@@ -1,6 +1,6 @@
 /**
  * LPC utility code
- * Copyright (c) 2006  Justin Ruggles <jruggle@earthlink.net>
+ * Copyright (c) 2006  Justin Ruggles <justin.ruggles@gmail.com>
  *
  * This file is part of FFmpeg.
  *
@@ -21,50 +21,11 @@
 
 #include "libavutil/lls.h"
 #include "dsputil.h"
+
+#define LPC_USE_DOUBLE
 #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, i2;
-   double r, err, tmp;
-   double lpc_tmp[MAX_LPC_ORDER];
-
-   for(i=0; i<max_order; i++) lpc_tmp[i] = 0;
-   err = autoc[0];
-
-   for(i=0; i<max_order; i++) {
-      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);
-
-      i2 = (i >> 1);
-      lpc_tmp[i] = r;
-      for(j=0; j<i2; j++) {
-         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;
-      }
-
-      for(j=0; j<=i; j++) {
-          lpc[i][j] = -lpc_tmp[j];
-      }
-   }
-}
-
 /**
  * Quantize LPC coefficients
  */
@@ -110,7 +71,7 @@ static void quantize_lpc_coefs(double *lpc_in, int order, int precision,
     /* 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];
     }
@@ -151,7 +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;
@@ -183,7 +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--)