Merge commit 'b78c30d7ec26af67c00ce2002709a189f6a87a7e'

* commit 'b78c30d7ec26af67c00ce2002709a189f6a87a7e':
  lavc: Add mpeg2_metadata bitstream filter
  lavc: Add coded bitstream read/write support for MPEG-2
  cbs_h2645: Return error if writing fails
  h264dec: use a large enough field for reference list modification values
  xwddec: support 8bpp grayscale

This commit is a noop, see
b9c94e826e7551027754ecfa60e3e487e0c28fcb
2aff557c6acbce2b2b604c6c620c66c892260062
b4c915f4b3e15c3e787e319b961e4389762f6309
686e388bbb6aeef077095a83f84b53d143d44d63
569721ac8dee6b73cd68ea858f59c7d800a1686d

Merged-by: James Almer <jamrial@gmail.com>