vf_aspect: support variables in evaluating the aspect ratios

Example: -vf setsar=sar="sar*9/10"

Signed-off-by: Rudolf Polzer <divverent@xonotic.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
vf_scale: make the dar variable return the DAR.

Before, it just returned width/height. Correct is width/height*sar.

That way it is consistent with DAR as in probe output and setdar.

Signed-off-by: Rudolf Polzer <divverent@xonotic.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavd/alsa: fix timestamp calculation

Current implementation didn't include duration of
last processed packet.
Device may return negative timestamps without
this correction.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
lavd/alsa: add stream validation

Don't trust provided streams.
Return with error when stream count is not 1 or
provided stream is not an audio stream.

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
lavf/wavenc: check for a single stream.

Fix trac ticket #3110.
lavd/lavfi: support unknown channel layouts.
lavfi/avfiltergraph: suggest a solution when format selection fails.

Format selection can fail if unknown channel layouts are used
with filters that do not support it.
lavfi/avfiltergraph: do not reduce incompatible lists.

A list of "all channel layouts" but not "all channel counts"
can not be reduced to a single unknown channel count.
lavfi: parsing helper for unknown channel layouts.

Make ff_parse_channel_layout() accept unknown layouts too.
lswr: fix assert failure on unknown layouts.
lavfi/af_pan: support unknown layouts on output.
lavfi/af_pan: support unknown layouts on input.

Fix trac ticket #2899.
attributes: disable flatten on llvm/clang
wtv: fix variable sign in format
ansi: fix possible use of uninitialized variables
rtmpproto: Reorder conditions to help dead code elimination

This makes sure that these branches are eliminated properly
with clang with optimizations disabled.
Merge commit '34a0ac41a880039c7fb4b3abce10d8e2ce48fac7'

* commit '34a0ac41a880039c7fb4b3abce10d8e2ce48fac7':
  vf_aspect: support variables in evaluating the aspect ratios

Conflicts:
	Changelog
	doc/filters.texi
	libavfilter/vf_aspect.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '3a14b160bd442794c6a16a6a883adb547550e847'

* commit '3a14b160bd442794c6a16a6a883adb547550e847':
  vf_scale: make the dar variable return the DAR.

Conflicts:
	Changelog
	doc/filters.texi
	libavfilter/version.h

See: 61d55fda2b513caf18e37b27aba680a87840904a
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '5858a67f135a7395c548482c73cf3d39bcdd3022'

* commit '5858a67f135a7395c548482c73cf3d39bcdd3022':
  attributes: disable flatten on llvm/clang

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'c0bba95c2363641d3297b3852b2ece1474cda295'

* commit 'c0bba95c2363641d3297b3852b2ece1474cda295':
  wtv: fix variable sign in format

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