Fixes undefined behaviour and a gcc warning:
libswresample/rematrix.c:376:47: warning: iteration 64 invokes undefined behavior

Fixes Ticket #5897.

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

API and Doxy documentation is taken from avresample_build_matrix()
Fixes: Ticket5780

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

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

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

This fixes the sum of the integer coefficients ending up summing to a value
larger than the value representing unity.

This issue occurs with qN0.dts when converting to stereo

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

This is the matrix that will be used for up/downmixing.

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

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

This avoids several issue like calculating sum/maxcoef
incorrectly due to adding up matrix entries that will
be overwritten, as well as out-of-range writes to
s->matrix if the maximum allowed number of channels is used.

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

A branch to avoid some calculation seems unlikely to have any benefits.

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

We only actually need to use a tiny part of it.
Unfortunately we seem to have no real test coverage on
the code, so this is a bit risky.

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

Fixes Ticket 3542

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

Fixes Ticket2859

Note, testcases related to the downmix channels are welcome.
(id like to make sure this is working correctly now, as obviously it didnt
 work before ...)

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>

Needed for dithering S32

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

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

Also remove it in once case when it is not needed.

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

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

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

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

Based on code by John Stebbins
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

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

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

Based on code by John Stebbins <jstebbins.hb@gmail.com>

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>

Help debugging.

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>