The implementation is pretty straight-forward. Most of the existing
NV12 codepaths work regardless of subsampling and are re-used as is.
Where necessary I wrote the slightly different NV24 versions.

Finally, the one thing that confused me for a long time was the
asm specific x86 path that did an explicit exclusion check for NV12.
I replaced that with a semi-planar check and also updated the
equivalent PPC code, which Lauri kindly checked.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Found-by: Luca Barbato
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Implemented for AV_PIX_FMT_GBRP12.

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

It is used to select functions that work with 9-15bits.

See merge commit '39d6d3618d48625decaff7d9bdbb45b44ef2a805'.

These warnings conflict with system macros on Solaris, producing
truckloads of warnings about macro redefinition.

Removed previous swscale code under '#ifndef NEW_FILTER'
and removed unused fields of SwsContext

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

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

Can be tested with:
$ ./configure --cc='cc -m32' --disable-optimizations --enable-pic

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

This is part of the patch-set for intel C inline asm on windows support

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

Also give consistent names to init functions.

This tries to compensate for the errors introduced by
the rounding of pmulhw

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

Refactoring mmx2/mmxext YASM code with cpuflags will force renames.
So switching to a consistent naming scheme beforehand is sensible.
The name "mmxext" is more official and widespread and also the name
of the CPU flag, as reported e.g. by the Linux kernel.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixes overflows for large image sizes.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org

Revert "swscale: update context offsets after removal of AlpMmxFilter."
(commit a95e3fa90b)
and
Revert "swscale: Remove some write-only variables related to alpha handling."
(commit 9d03cb9fc5).

They broke alpha handling - it's the evil inline asm that still uses that
variable, so it's not truely write-only.

Prevents crashes on 1-tap filter (unscaled). Also rename "bguf" argument
to "vbuf", seems that was a typo.

Fixes bug 221.

CC: libav-stable@libav.org

Also implement sse2/ssse3/avx versions.

Additional comments from Måns Rullgard have been integrated
by Reinhard Tartler.

Signed-off-by: Reinhard Tartler <siretart@tauware.de>

Also implement SSE2/AVX variants.

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

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

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

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

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

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

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

Also implement MMX/MMX2 versions and SSE4 versions.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

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

Replaces a very hackish hack to fix the same issue (call instruction
overwriting stack variables).

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

gcc 4.6 no longer decrements esp to account for local variables.
Thus using call will end up overwriting some local variable.
So add an extra one it can safely clobber.
This is a huge hack because it's basically pure chance it works,
no idea how this is supposed to be done.

Fixes trac ticket #397.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

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

Speed: from 3.9x to 9.6x speed improvement over C, and some small
(up to 15%) speed improvements over existing MMX code (particularly
for bigger filters).

Author of the fix is ronald, the enabling & commit message are mine.

This fixes
	commit 4e3e333a79
	Author: Ronald S. Bultje <rsbultje@gmail.com>
	Date:   Tue Jul 5 12:49:11 2011 -0700

	    swscale: error dithering for 16/9/10-bit to 8-bit.

	    Based on a somewhat similar idea in FFmpeg's swscale copy.

The Fix was originally commited in: (and i missed it due to the commit message)
	commit 5c391a161a
	Author: Ronald S. Bultje <rsbultje@gmail.com>
	Date:   Fri Jul 8 14:39:04 2011 -0700

	    swscale: rename uv_off/uv_off2 to uv_off_px/byte.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

This allows using more specific implementations for chroma/luma, e.g.
we can make assumptions on filterSize being constant, thus avoiding
that test at runtime.

Based on a somewhat similar idea in FFmpeg's swscale copy.