libavcodec/ac3enc.c:891: error: Buffer Overrun L3
  Offset: [-1, 4] Size: 6.

libavcodec/ac3enc.c:887:10: <Offset trace>
885.     int blk, ch;
886. 
887.     for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
              ^
888.         AC3Block *block = &s->blocks[blk];
889.         for (ch = 0; ch < s->channels; ch++) {

libavcodec/ac3enc.c:887:10: Assignment
885.     int blk, ch;
886. 
887.     for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
              ^
888.         AC3Block *block = &s->blocks[blk];
889.         for (ch = 0; ch < s->channels; ch++) {

libavcodec/ac3enc.c:883:1: <Length trace>
881.  * Also calculate the power spectral densities to use in future calculations.
882.  */
883. static void bit_alloc_masking(AC3EncodeContext *s)
     ^
884. {
885.     int blk, ch;

libavcodec/ac3enc.c:883:1: Parameter `s->blocks[*]`
881.  * Also calculate the power spectral densities to use in future calculations.
882.  */
883. static void bit_alloc_masking(AC3EncodeContext *s)
     ^
884. {
885.     int blk, ch;

libavcodec/ac3enc.c:891:17: Array access: Offset: [-1, 4] Size: 6
889.         for (ch = 0; ch < s->channels; ch++) {
890.             if (block->exp_strategy[ch] == EXP_REUSE) {
891.                 AC3Block *block1 = &s->blocks[blk-1];
                     ^
892.                 memcpy(block->psd[ch],  block1->psd[ch],  AC3_MAX_COEFS*sizeof(block->psd[0][0]));
893.                 memcpy(block->mask[ch], block1->mask[ch], AC3_CRITICAL_BANDS*sizeof(block->mask[0][0]));
