Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>

Fixes ticket #5100.

Fix possible SF delta violation that would cause an
eventual assertion failure in some corner cases (esp
on very low bitrates) when marking bands for PNS due
to misuse of the sf_delta utilities

'erf' is far from the best name for a variable and is not very
descriptive since the actual variable points to the comparitively best
IS phase. Therefore rename it to 'best'.
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

Source code is from Boost:
http://www.boost.org/doc/libs/1_46_1/boost/math/special_functions/erf.hpp
with appropriate modifications for FFmpeg.

Tested on interval -6 to 6 (beyond which it saturates), +/-NAN, +/-INFINITY
under -fsanitize=undefined on clang to test for possible undefined behavior.

This function turns out to actually be essentially as accurate and faster than the
libm (GNU/BSD's/Mac OS X), and I can think of 3 reasons why upstream
does not use this:
1. They are not aware of it.
2. They are concerned about licensing - this applies especially to GNU
libm.
3. They do not know and/or appreciate the benefits of rational
approximations over polynomial approximations. Boost uses them to great
effect, see e.g swr/resample for bessel derived from them, which is also
similarly superior to libm variants.

First, performance.
sample benchmark (clang -O3, Haswell, GNU/Linux):

3e8 values evenly spaced from 0 to 6
time (libm):
./test  13.39s user 0.00s system 100% cpu 13.376 total
time (boost based):
./test  9.20s user 0.00s system 100% cpu 9.190 total

Second, accuracy.
1e8 eval pts from 0 to 6
maxdiff (absolute): 2.2204460492503131e-16
occuring at point where libm erf is correctly rounded, this is not.

Illustration of superior rounding of this function:
arg   : 0.83999999999999997
erf   : 0.76514271145499457
boost : 0.76514271145499446
real  : 0.76514271145499446

i.e libm is actually incorrectly rounded. Note that this is clear from:
https://github.com/JuliaLang/openlibm/blob/master/src/s_erf.c (the Sun
implementation used by both BSD and GNU libm's), where only 1 ulp is
guaranteed.

Reasons it is not easy/worthwhile to create a "correctly rounded"
variant of this function (i.e 0.5ulp):
1. Upstream libm's don't do it anyway, so we can't guarantee this unless
we force this implementation on all platforms. This is not easy, as the
linker would complain unless measures are taken.
2. Nothing in FFmpeg cares or can care about such things, due to the
above and FFmpeg's nature.
3. Creating a correctly rounded function will in practice need some use of long
double/fma. long double, although C89/C90, unfortunately has problems on
ppc. This needs fixing of toolchain flags/configure. In any case this
will be slower for miniscule gain.
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

May be useful as a defense, see e.g c62d1780.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

Here it is mostly a cosmetic change, but there might be benefits in that
there are no compat hacks for lround, while there are for lrint.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

lrint is at least as fast, uses a superior rounding mode, and avoids an
implicit cast.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

lrint is at least as fast, uses a superior rounding mode, and avoids an
implicit cast.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

lrint is at least as fast, avoids an implicit cast, and uses a superior
rounding mode.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

Mostly cosmetic here.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

llrint is at least as fast, and avoids an implicit cast.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

lrint avoids an implicit cast, and is not slower on non-broken libm's. Thus this
represents a Pareto improvement.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

lrint is faster here on -ftree-vectorize with GCC. This is likely simply
an artifact of GCC's rather terrible auto-vectorizer, since as per the
instruction set manuals cvtsd2si and cvttsd2si (or their vector equivalents)
have identical cycle timings.

Anyway, regardless of above, lrint is superior to round accuracy wise.

Safety guaranteed as long int has at least 32 bits.
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

Signed-off-by: Paul B Mahol <onemda@gmail.com>

This behaviour change caused a regression on our side recently, we might
want to disable the option by default.

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Reviewed-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Reviewed-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Reviewed-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Signed-off-by: Paul B Mahol <onemda@gmail.com>

This disallows creating unplayable audio.
Signed-off-by: Paul B Mahol <onemda@gmail.com>

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

Otherwise the too small buffer is directly used in the frame, causing
segmentation faults, when trying to use the frame.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

This fixes NULL pointer dereferencing.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

Fixes assertion failure
Fixes: id_acf3e47f864e1ee4c7b86c0653e0ff31e5bde56e.m4v
Found-by: Andreas Cadhalpun <andreas.cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

For systems with broken libms.
Tested with NAN, -NAN, INFINITY, -INFINITY, +/-x for regular double x and
combinations of these.

Old versions of MSVC need some UINT64_C hackery.
Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Reviewed-by: Hendrik Leppkes <h.leppkes@gmail.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>

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

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Fixes out of array read
Fixes mozilla bug 1233606

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

This disables the 32bit precision neon code path in favor of the
default C one and avoids breaking fate.

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