AES_BLOCK_SIZE     31 libavutil/aes_ctr.c     uint8_t counter[AES_BLOCK_SIZE];
AES_BLOCK_SIZE     32 libavutil/aes_ctr.c     uint8_t encrypted_counter[AES_BLOCK_SIZE];
AES_BLOCK_SIZE    125 libavutil/aes_ctr.c         cur_end_pos = src + AES_BLOCK_SIZE - a->block_offset;
AES_BLOCK_SIZE    129 libavutil/aes_ctr.c         a->block_offset &= (AES_BLOCK_SIZE - 1);