libavcodec/amrwbdec.c:943: error: Uninitialized Value
  The value read from diff_isf[_] was never initialized.

libavcodec/amrwbdec.c:943:13: 
941.     /* Stability insurance */
942.     for (i = 1; i < LP_ORDER_16k - LP_ORDER; i++)
943.         if (diff_isf[i] + diff_isf[i - 1] < 5.0) {
                 ^
944.             if (diff_isf[i] > diff_isf[i - 1]) {
945.                 diff_isf[i - 1] = 5.0 - diff_isf[i];

static void extrapolate_isf(float isf[LP_ORDER_16k])
{
    float diff_isf[LP_ORDER - 2], diff_mean;
    float corr_lag[3];
    float est, scale;
    int i, j, i_max_corr;
    isf[LP_ORDER_16k - 1] = isf[LP_ORDER - 1];
    for (i = 0; i < LP_ORDER - 2; i++)
        diff_isf[i] = isf[i + 1] - isf[i];
    diff_mean = 0.0;
    for (i = 2; i < LP_ORDER - 2; i++)
        diff_mean += diff_isf[i] * (1.0f / (LP_ORDER - 4));
    i_max_corr = 0;
    for (i = 0; i < 3; i++) {
        corr_lag[i] = auto_correlation(diff_isf, diff_mean, i + 2);
        if (corr_lag[i] > corr_lag[i_max_corr])
            i_max_corr = i;
    }
    i_max_corr++;
    for (i = LP_ORDER - 1; i < LP_ORDER_16k - 1; i++)
        isf[i] = isf[i - 1] + isf[i - 1 - i_max_corr]
                            - isf[i - 2 - i_max_corr];
    est   = 7965 + (isf[2] - isf[3] - isf[4]) / 6.0;
    scale = 0.5 * (FFMIN(est, 7600) - isf[LP_ORDER - 2]) /
            (isf[LP_ORDER_16k - 2] - isf[LP_ORDER - 2]);
    for (i = LP_ORDER - 1, j = 0; i < LP_ORDER_16k - 1; i++, j++)
        diff_isf[j] = scale * (isf[i] - isf[i - 1]);
    for (i = 1; i < LP_ORDER_16k - LP_ORDER; i++)
        if (diff_isf[i] + diff_isf[i - 1] < 5.0) {
            if (diff_isf[i] > diff_isf[i - 1]) {
                diff_isf[i - 1] = 5.0 - diff_isf[i];
            } else
                diff_isf[i] = 5.0 - diff_isf[i - 1];
        }
    for (i = LP_ORDER - 1, j = 0; i < LP_ORDER_16k - 1; i++, j++)
        isf[i] = isf[i - 1] + diff_isf[j] * (1.0f / (1 << 15));
    for (i = 0; i < LP_ORDER_16k - 1; i++)
        isf[i] *= 0.8;
}
['static void extrapolate_isf(float isf[LP_ORDER_16k])\n{\n    float diff_isf[LP_ORDER - 2], diff_mean;\n    float corr_lag[3];\n    float est, scale;\n    int i, j, i_max_corr;\n    isf[LP_ORDER_16k - 1] = isf[LP_ORDER - 1];\n    for (i = 0; i < LP_ORDER - 2; i++)\n        diff_isf[i] = isf[i + 1] - isf[i];\n    diff_mean = 0.0;\n    for (i = 2; i < LP_ORDER - 2; i++)\n        diff_mean += diff_isf[i] * (1.0f / (LP_ORDER - 4));\n    i_max_corr = 0;\n    for (i = 0; i < 3; i++) {\n        corr_lag[i] = auto_correlation(diff_isf, diff_mean, i + 2);\n        if (corr_lag[i] > corr_lag[i_max_corr])\n            i_max_corr = i;\n    }\n    i_max_corr++;\n    for (i = LP_ORDER - 1; i < LP_ORDER_16k - 1; i++)\n        isf[i] = isf[i - 1] + isf[i - 1 - i_max_corr]\n                            - isf[i - 2 - i_max_corr];\n    est   = 7965 + (isf[2] - isf[3] - isf[4]) / 6.0;\n    scale = 0.5 * (FFMIN(est, 7600) - isf[LP_ORDER - 2]) /\n            (isf[LP_ORDER_16k - 2] - isf[LP_ORDER - 2]);\n    for (i = LP_ORDER - 1, j = 0; i < LP_ORDER_16k - 1; i++, j++)\n        diff_isf[j] = scale * (isf[i] - isf[i - 1]);\n    for (i = 1; i < LP_ORDER_16k - LP_ORDER; i++)\n        if (diff_isf[i] + diff_isf[i - 1] < 5.0) {\n            if (diff_isf[i] > diff_isf[i - 1]) {\n                diff_isf[i - 1] = 5.0 - diff_isf[i];\n            } else\n                diff_isf[i] = 5.0 - diff_isf[i - 1];\n        }\n    for (i = LP_ORDER - 1, j = 0; i < LP_ORDER_16k - 1; i++, j++)\n        isf[i] = isf[i - 1] + diff_isf[j] * (1.0f / (1 << 15));\n    for (i = 0; i < LP_ORDER_16k - 1; i++)\n        isf[i] *= 0.8;\n}']