@@ -155,20 +155,19 @@ static void lsp2polyf(const double *lsp, double *f, int lp_half_order)

     }

 }

-void ff_acelp_lspd2lpc(const double *lsp, float *lpc)

+void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order)

 {

-    double pa[6], qa[6];

-    int   i;

+    double pa[lp_half_order+1], qa[lp_half_order+1];

+    float *lpc2 = lpc + (lp_half_order << 1) - 1;

-    lsp2polyf(lsp,     pa, 5);

-    lsp2polyf(lsp + 1, qa, 5);

+    lsp2polyf(lsp,     pa, lp_half_order);

+    lsp2polyf(lsp + 1, qa, lp_half_order);

-    for (i=4; i>=0; i--)

-    {

-        double paf = pa[i+1] + pa[i];

-        double qaf = qa[i+1] - qa[i];

+    while (lp_half_order--) {

+        double paf = pa[lp_half_order+1] + pa[lp_half_order];

+        double qaf = qa[lp_half_order+1] - qa[lp_half_order];

-        lpc[i  ] = 0.5*(paf+qaf);

-        lpc[9-i] = 0.5*(paf-qaf);

+        lpc [ lp_half_order] = 0.5*(paf+qaf);

+        lpc2[-lp_half_order] = 0.5*(paf-qaf);

     }

 }

@@ -86,8 +86,10 @@ void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd

  * @param lsp line spectral pairs in cosine domain

  * @param lpc linear predictive coding coefficients

  *

+ * @note buffers should have a minimux size of 2*lp_half_order elements.

+ *

  * TIA/EIA/IS-733 2.4.3.3.5

  */

-void ff_acelp_lspd2lpc(const double *lsp, float *lpc);

+void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order);

 #endif /* AVCODEC_LSP_H */

@@ -578,7 +578,7 @@ static void lspf2lpc(const float *lspf, float *lpc)

     for (i=0; i<10; i++)

         lsp[i] = cos(M_PI * lspf[i]);

-    ff_acelp_lspd2lpc(lsp, lpc);

+    ff_acelp_lspd2lpc(lsp, lpc, 5);

     for (i=0; i<10; i++)

     {