This update for ffmpeg fixes the following issues:

- CVE-2018-13300: An improper argument passed to the avpriv_request_sample
  function may have triggered an out-of-array read while converting a crafted AVI
  file to MPEG4, leading to a denial of service and possibly an information
  disclosure (bsc#1100348)
- CVE-2018-15822: The flv_write_packet function did not check for an empty
  audio packet, leading to an assertion failure and DoS (bsc#1105869)
- CVE-2018-13305: Due to a missing check for negative values of the mquant
  variable, the vc1_put_blocks_clamped function in libavcodec/vc1_block.c
  may trigger an out-of-array access while converting a crafted AVI
  file to MPEG4, leading to an information disclosure or a denial of
  service. (bsc#1100345).
- CVE-2018-12458: An improper integer type in the mpeg4_encode_gop_header
  function in libavcodec/mpeg4videoenc.c might have triggered an assertion
  violation while converting a crafted AVI file to MPEG4, leading to a
  denial of service. (bsc#1097983).