Security:
* Fix a buffer overflow in the MKV demuxer (CVE-2019-14970)
* Fix a read buffer overflow in the avcodec decoder (CVE-2019-13962)
* Fix a read buffer overflow in the FAAD decoder
* Fix a read buffer overflow in the OGG demuxer (CVE-2019-14437, CVE-2019-14438)
* Fix a read buffer overflow in the ASF demuxer (CVE-2019-14776)
* Fix a use after free in the MKV demuxer (CVE-2019-14777, CVE-2019-14778)
* Fix a use after free in the ASF demuxer (CVE-2019-14533)
* Fix a couple of integer underflows in the MP4 demuxer (CVE-2019-13602)
* Fix a null dereference in the dvdnav demuxer
* Fix a null dereference in the ASF demuxer (CVE-2019-14534)
* Fix a null dereference in the AVI demuxer
* Fix a division by zero in the CAF demuxer (CVE-2019-14498)
* Fix a division by zero in the ASF demuxer (CVE-2019-14535)