This is more spec-compliant because it does not rely
on dead-code elimination by the compiler. Especially
MSVC has problems with this, as can be seen in
https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/296373.html
or
https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/297022.html
This commit does not eliminate every instance where we rely
on dead code elimination: It only tackles branching to
the initialization of arch-specific dsp code, not e.g. all
uses of CONFIG_ and HAVE_ checks. But maybe it is already
enough to compile FFmpeg with MSVC with whole-programm-optimizations
enabled (if one does not disable too many components).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Fixes: signed integer overflow: 1515225320 + 759416059 cannot be represented in type 'int'
Fixes: 29256/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DCA_fuzzer-5719088561258496
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Up to ~4 times faster on x86_64, ~8 times on x86_32 if compiling using x87 fp math.
Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
The DCA core decoder converts integer coefficients read from the
bitstream to floats just after reading them (along with dequantization).
All the other steps of the audio reconstruction are done with floats
which makes the output for the DTS lossless extension (XLL)
actually lossy.
This patch changes the DCA core to work with integer coefficients
until QMF. At this point the integer coefficients are converted to floats.
The coefficients for the LFE channel (lfe_data) are not touched.
This is the first step for the really lossless XLL decoding.
The vector dequantization has a test in a loop preventing effective SIMD
implementation. By moving it out of the loop, this loop can be DSPized.
Therefore, modify the current DSP implementation. In particular, the
DSP implementation no longer has to handle null loop sizes.
The decode_hf implementations have following timings:
For x86 Arrandale:
C SSE SSE2 SSE4
win32: 260 162 119 104
win64: 242 N/A 89 72
The arm NEON optimizations follow in a later patch as external asm. The
now unused check for the y modifier in arm inline asm is removed from
configure.
The scaling factor is constant so it is faster to scale the
FIR coefficients in the tables during compilation.
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
The x86 runs short on registers because numerous elements are not static.
In addition, splitting them allows more optimized code, at least for x86.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
It is currently declared as a macro who is set to inlinable functions,
among which a Neon and a default C implementations.
Add a DSP parameter to each inline function, unused except by the
default C implementation which calls a function from the DSP context.
On an Arrandale CPU, gain for an inlined SSE2 function vs. a call:
- Win32: 29 to 26 cycles
- Win64: 25 to 23 cycles
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The x86 runs short on registers because numerous elements are not static.
In addition, splitting them allows more optimized code, at least for x86.
Arm asm changes by Janne Grunau.
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
For the callable function (as opposed to the inline one):
C SSE SSE2 SSE4
Win32: 47 42 29 26
Win64: 30 33 25 23
The SSE version is neither compiled nor set for ARCH_X86_64, as the
inlinable function takes over.
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
It is currently declared as a macro who is set to inlinable functions,
among which a Neon and a default C implementations.
Add a DSP parameter to each inline function, unused except by the
default C implementation which calls a function from the DSP context.
On an Arrandale CPU, gain for an inlined SSE2 function vs. a call:
- Win32: 29 to 26 cycles
- Win64: 25 to 23 cycles
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
This reduces the number of false dependencies on header files and
speeds up compilation.
Originally committed as revision 22407 to svn://svn.ffmpeg.org/ffmpeg/trunk
Consistently apply this rule: the guard name is obtained from the
filename by stripping the leading "lib", converting '/' and '.' to
'_' and uppercasing the resulting name. Guard names in the root
directory have to be prefixed by "FFMPEG_".
Originally committed as revision 15120 to svn://svn.ffmpeg.org/ffmpeg/trunk
Patch by Zuxy Meng: zuxy meng gmail com
Original thread:
[FFmpeg-devel] [PATCH] Pure, const and malloc attributes to libavutil
Date: 03/18/2008 6:09 AM
Originally committed as revision 12489 to svn://svn.ffmpeg.org/ffmpeg/trunk
Andreas Rheinhardt
Michael Niedermayer
Anton Khirnov
foo86
James Almer
Alexandra Hájková
Janne Grunau
Gabriel Dume
Christophe Gisquet
Ben Avison
Diego Biurrun
Mans Rullgard
Justin Ruggles
Stefano Sabatini
Zuxy Meng
Benoit Fouet