hevc: check that the VCL NAL types are the same for all slice segments of a frame

Fixes possible invalid memory access for mismatching skipped/non-skipped
slice segments.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Sample-Id: 00001533-google
vf_overlay: add eof_action switch

Signed-off-by: Anton Khirnov <anton@khirnov.net>
utvideoenc: Add support for the new BT.709 FourCCs for YCbCr

With cli usage the decoder might have not set the colorspace during
encoder init, manual colorspace override might be needed in such
cases.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavf: do basic sanity checking on muxed packets

Reject packets for non-existing or attachment streams.
lavf: ignore attachment streams for interleaving purposes

Those streams should never get any packets by definition.
Merge commit 'b25e84b7399bd91605596b67d761d3464dbe8a6e'

* commit 'b25e84b7399bd91605596b67d761d3464dbe8a6e':
  hevc: check that the VCL NAL types are the same for all slice segments of a frame

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'de203abd71baae7f120313259b45cf935c85203e'

* commit 'de203abd71baae7f120313259b45cf935c85203e':
  vf_overlay: add eof_action switch

Conflicts:
	doc/filters.texi
	libavfilter/vf_overlay.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avfilter/dualinput: fix repeatlast to match docs and eof_action=pass

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '5de64bb34d68d6c224dca90003172d7a27958825'

* commit '5de64bb34d68d6c224dca90003172d7a27958825':
  utvideoenc: Add support for the new BT.709 FourCCs for YCbCr

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '7b03b65bf0d02519c86750d2da33f413e11cf0c6'

* commit '7b03b65bf0d02519c86750d2da33f413e11cf0c6':
  lavf: do basic sanity checking on muxed packets

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '33c859c142ef3f49b7a6227014ad92a680cf4d74'

* commit '33c859c142ef3f49b7a6227014ad92a680cf4d74':
  lavf: ignore attachment streams for interleaving purposes

Conflicts:
	libavformat/avformat.h
	libavformat/internal.h
	libavformat/mux.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
ffserver: use avformat_alloc_context()

Fixes null pointer dereference

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>