It appears someone thinks this special case can be reached
Well, it cannot, thus not only do we not need to optimize it
we dont need it at all
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master: (22 commits)
g723.1: do not pass large structs by value
g723.1: do not bounce intermediate values via memory
g723.1: declare a variable in the block it is used
g723.1: avoid saving/restoring excitation
g723.1: avoid unnecessary memcpy() in residual_interp()
g723.1: make postfilter write directly to output buffer
g723.1: drop unnecessary variable buf_ptr in formant_postfilter()
g723.1: make scale_vector() output to a separate buffer
g723.1: make autocorr_max() work on an arbitrary buffer
g723.1: do not needlessly use int64_t
g723.1: use saturating addition functions
g723.1: optimise scale_vector()
g723.1: remove useless uses of MUL64()
g723.1: remove unnecessary argument 'shift' from dot_product()
g723.1: deobfuscate "(x << 4) - x" to "15 * x"
celp: optimise ff_celp_lp_synthesis_filter()
libavutil: add saturating addition functions
cllc: Implement ARGB support
cllc: Add support for QRGB
cllc: Rename some funcs to represent what they actually do
...
Conflicts:
LICENSE
libavcodec/g723_1.c
libavcodec/x86/Makefile
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Although a reasonable compiler will probably optimise out the
actual store and load, this operation still implies a truncation
to 16 bits which the compiler will probably not realise is not
necessary here.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Writing the scaled excitation to a scratch buffer (borrowing the
'audio' array) instead of modifying it in place avoids the need
to save and restore the unscaled values.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Use saturating addition functions instead of 64-bit intermediates
and separate clipping. This is much faster when dedicated
instructions are available.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Firstly, nothing in this function can overflow 32 bits so the use
of a 64-bit type is completely unnecessary. Secondly, the scale
is either a power of two or 0x7fff. Doing separate loops for these
cases avoids using multiplications. Finally, since only the number
of bits, not the actual value, of the maximum value is needed, the
bitwise or of all the values serves the purpose while being faster.
It is worth noting that even if overflow could happen, it was not
handled correctly anyway.
Signed-off-by: Mans Rullgard <mans@mansr.com>
The operands in both cases are 16-bit so cannot overflow a 32-bit
destination. In gain_scale() the inputs are reduced to 14-bit,
so even the shift cannot overflow.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Adding instead of subtracting the products in the loop allows the
compiler to generate more efficient multiply-accumulate instructions
when 16-bit multiply-subtract is not available. ARM has only
multiply-accumulate for 16-bit operands. In general, if only one
variant exists, it is usually accumulate rather than subtract.
In the same spirit, using the dedicated saturation function enables
use of any special optimised versions of this.
Signed-off-by: Mans Rullgard <mans@mansr.com>
C++ does not allow to mix different enums, so e.g. code comparing
ACodecID with CodecID would fail to compile with gcc.
This very evil hack should fix this problem.
* qatar/master:
g723.1: fix addition overflow
g723.1: simplify and fix multiplication overflow
g723.1: deobfuscate an expression
g723.1: remove unused #includes
ARM: add missing "cc" clobber in av_clipl_int32_arm()
rtmp: Factorize the code by adding handle_invoke_error
rtmp: Factorize the code by adding handle_invoke_status
rtmp: Factorize the code by adding handle_invoke_result
libavutil: remove unused av_abort() macro
ffmenc: replace if/abort with assert()
libavutil: drop offsetof() fallback definition
libavutil: drop fallback definitions of INTxx_MIN/MAX
configure: Check for a sctp struct instead of just the header
configure: suncc: Add -xc99 to dependency flags, required on Solaris
doxygen: Fix function parameter names to match the code
doc: Drop obsolete shared libs cflags hint to workaround Cygwin gcc bugs
swf: Move shared table out of the header file
swf: Move swf_audio_codec_tags table to the only place it is used
fate: add G.723.1 decoder tests
Conflicts:
configure
doc/platform.texi
libavformat/Makefile
libavutil/arm/intmath.h
Merged-by: Michael Niedermayer <michaelni@gmx.at>
In 16-bit arithmetic, x * 0xffffc is simply x * -4 with extra overflows,
(and the constant was probably meant to be 0xfffc). Combined with the
shift, this simplifies to -x >> 1. Finally, clearing the low two bits
with a 32-bit mask and switching to a 32-bit type allows more efficient
code on 32-bit machines.
Signed-off-by: Mans Rullgard <mans@mansr.com>
