g723_1: save/restore excitation with offset to store LPC history

The same buffer with saved data is used later in LPC reconstruction, so
it should have some head space for LPC history.

diff --git a/libavcodec/g723_1.c b/libavcodec/g723_1.c
index df14a46..11e90e8 100644 (file)
--- a/libavcodec/g723_1.c
+++ b/libavcodec/g723_1.c
@@ -1071,7 +1071,7 @@ static int g723_1_decode_frame(AVCodecContext *avctx, void *data,
             vector_ptr = p->excitation + PITCH_MAX;
 
             /* Save the excitation */
-            memcpy(p->audio, vector_ptr, FRAME_LEN * sizeof(*p->audio));
+            memcpy(p->audio + LPC_ORDER, vector_ptr, FRAME_LEN * sizeof(*p->audio));
 
             p->interp_index = comp_interp_index(p, p->pitch_lag[1],
                                                 &p->sid_gain, &p->cur_gain);
@@ -1086,7 +1086,7 @@ static int g723_1_decode_frame(AVCodecContext *avctx, void *data,
             /* Restore the original excitation */
             memcpy(p->excitation, p->prev_excitation,
                    PITCH_MAX * sizeof(*p->excitation));
-            memcpy(vector_ptr, p->audio, FRAME_LEN * sizeof(*vector_ptr));
+            memcpy(vector_ptr, p->audio + LPC_ORDER, FRAME_LEN * sizeof(*vector_ptr));
 
             /* Peform pitch postfiltering */
             if (p->postfilter)