@@ -194,6 +194,7 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,

                            int lpc_order, int lpc_quant)

 {

     int i;

+    int32_t *pred = buffer_out;

     /* first sample always copies */

     *buffer_out = *error_buffer;

@@ -217,37 +218,35 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,

     }

     /* read warm-up samples */

-    for (i = 0; i < lpc_order; i++) {

-        buffer_out[i + 1] = sign_extend(buffer_out[i] + error_buffer[i + 1],

-                                        bps);

-    }

+    for (i = 1; i <= lpc_order; i++)

+        buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);

     /* NOTE: 4 and 8 are very common cases that could be optimized. */

-    for (i = lpc_order; i < nb_samples - 1; i++) {

+    for (; i < nb_samples; i++) {

         int j;

         int val = 0;

-        int error_val = error_buffer[i + 1];

+        int error_val = error_buffer[i];

         int error_sign;

-        int d = buffer_out[i - lpc_order];

+        int d = *pred++;

         /* LPC prediction */

         for (j = 0; j < lpc_order; j++)

-            val += (buffer_out[i - j] - d) * lpc_coefs[j];

+            val += (pred[j] - d) * lpc_coefs[j];

         val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;

         val += d + error_val;

-        buffer_out[i + 1] = sign_extend(val, bps);

+        buffer_out[i] = sign_extend(val, bps);

         /* adapt LPC coefficients */

         error_sign = sign_only(error_val);

         if (error_sign) {

-            for (j = lpc_order - 1; j >= 0 && error_val * error_sign > 0; j--) {

+            for (j = 0; j < lpc_order && error_val * error_sign > 0; j++) {

                 int sign;

-                val  = d - buffer_out[i - j];

+                val  = d - pred[j];

                 sign = sign_only(val) * error_sign;

                 lpc_coefs[j] -= sign;

                 val *= sign;

-                error_val -= (val >> lpc_quant) * (lpc_order - j);

+                error_val -= (val >> lpc_quant) * (j + 1);

             }

         }

     }

@@ -350,7 +349,7 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,

             lpc_order[ch]         = get_bits(&alac->gb, 5);

             /* read the predictor table */

-            for (i = 0; i < lpc_order[ch]; i++)

+            for (i = lpc_order[ch] - 1; i >= 0; i--)

                 lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);

         }