[FFmpeg-devel] [PATCHv3 2/2] all: move ff_exp10, ff_exp10f, ff_fast_powf to lavu/ffmath.h

Ronald S. Bultje rsbultje at gmail.com
Fri Mar 18 16:31:19 CET 2016


Hi,

On Fri, Mar 18, 2016 at 10:59 AM, Ganesh Ajjanagadde <gajjanag at gmail.com>
wrote:

> On Mon, Mar 14, 2016 at 7:05 PM, Ganesh Ajjanagadde <gajjanag at gmail.com>
> wrote:
> > The idea is to use ffmath.h for internal implementations of math
> functions.
> > Currently, it is used for variants of libm functions, but is by no means
> > limited to such things.
> >
> > Note that this is not exported; use lavu/mathematics for such purposes.
> >
> > Suggested-by: Ronald S. Bultje <rsbultje at gmail.com>
> > Signed-off-by: Ganesh Ajjanagadde <gajjanag at gmail.com>
> > ---
> >  libavcodec/aacenc_utils.h       |  2 +-
> >  libavcodec/aacpsy.c             |  3 +-
> >  libavcodec/acelp_pitch_delay.c  |  3 +-
> >  libavcodec/cngdec.c             |  2 +-
> >  libavcodec/dcaenc.c             |  2 +-
> >  libavcodec/imc.c                |  2 +-
> >  libavcodec/on2avc.c             |  2 +-
> >  libavcodec/opus.c               |  2 +-
> >  libavcodec/wmadec.c             |  3 +-
> >  libavcodec/wmaenc.c             |  2 +-
> >  libavcodec/wmaprodec.c          |  2 +-
> >  libavfilter/af_anequalizer.c    |  1 +
> >  libavfilter/af_compand.c        |  1 +
> >  libavfilter/af_volume.c         |  1 +
> >  libavfilter/f_ebur128.c         |  1 +
> >  libavfilter/vaf_spectrumsynth.c |  1 +
> >  libavfilter/vsrc_testsrc.c      |  1 +
> >  libavutil/eval.c                |  1 +
> >  libavutil/ffmath.h              | 67
> +++++++++++++++++++++++++++++++++++++++++
> >  libavutil/internal.h            | 36 ----------------------
> >  20 files changed, 85 insertions(+), 50 deletions(-)
> >  create mode 100644 libavutil/ffmath.h
> >
> > diff --git a/libavcodec/aacenc_utils.h b/libavcodec/aacenc_utils.h
> > index 07f7337..bb1dcb4 100644
> > --- a/libavcodec/aacenc_utils.h
> > +++ b/libavcodec/aacenc_utils.h
> > @@ -28,7 +28,7 @@
> >  #ifndef AVCODEC_AACENC_UTILS_H
> >  #define AVCODEC_AACENC_UTILS_H
> >
> > -#include "libavutil/internal.h"
> > +#include "libavutil/ffmath.h"
> >  #include "aac.h"
> >  #include "aacenctab.h"
> >  #include "aactab.h"
> > diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
> > index 8643fe7..0898baf 100644
> > --- a/libavcodec/aacpsy.c
> > +++ b/libavcodec/aacpsy.c
> > @@ -25,8 +25,7 @@
> >   */
> >
> >  #include "libavutil/attributes.h"
> > -#include "libavutil/internal.h"
> > -#include "libavutil/libm.h"
> > +#include "libavutil/ffmath.h"
> >
> >  #include "avcodec.h"
> >  #include "aactab.h"
> > diff --git a/libavcodec/acelp_pitch_delay.c
> b/libavcodec/acelp_pitch_delay.c
> > index c2533b1..8ec1ba3 100644
> > --- a/libavcodec/acelp_pitch_delay.c
> > +++ b/libavcodec/acelp_pitch_delay.c
> > @@ -21,9 +21,8 @@
> >   */
> >
> >  #include "libavutil/common.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/float_dsp.h"
> > -#include "libavutil/internal.h"
> > -#include "libavutil/libm.h"
> >  #include "libavutil/mathematics.h"
> >  #include "avcodec.h"
> >  #include "acelp_pitch_delay.h"
> > diff --git a/libavcodec/cngdec.c b/libavcodec/cngdec.c
> > index 0251086..34f8814 100644
> > --- a/libavcodec/cngdec.c
> > +++ b/libavcodec/cngdec.c
> > @@ -22,7 +22,7 @@
> >  #include <math.h>
> >
> >  #include "libavutil/common.h"
> > -#include "libavutil/internal.h"
> > +#include "libavutil/ffmath.h"
> >  #include "avcodec.h"
> >  #include "celp_filters.h"
> >  #include "internal.h"
> > diff --git a/libavcodec/dcaenc.c b/libavcodec/dcaenc.c
> > index 70e9230..ab40e37 100644
> > --- a/libavcodec/dcaenc.c
> > +++ b/libavcodec/dcaenc.c
> > @@ -24,7 +24,7 @@
> >  #include "libavutil/avassert.h"
> >  #include "libavutil/channel_layout.h"
> >  #include "libavutil/common.h"
> > -#include "libavutil/internal.h"
> > +#include "libavutil/ffmath.h"
> >  #include "avcodec.h"
> >  #include "dca.h"
> >  #include "dcadata.h"
> > diff --git a/libavcodec/imc.c b/libavcodec/imc.c
> > index 085ec09..850bc9d 100644
> > --- a/libavcodec/imc.c
> > +++ b/libavcodec/imc.c
> > @@ -35,9 +35,9 @@
> >  #include <stdio.h>
> >
> >  #include "libavutil/channel_layout.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/float_dsp.h"
> >  #include "libavutil/internal.h"
> > -#include "libavutil/libm.h"
> >  #include "avcodec.h"
> >  #include "bswapdsp.h"
> >  #include "get_bits.h"
> > diff --git a/libavcodec/on2avc.c b/libavcodec/on2avc.c
> > index 62c71cc..3064c6f 100644
> > --- a/libavcodec/on2avc.c
> > +++ b/libavcodec/on2avc.c
> > @@ -21,8 +21,8 @@
> >   */
> >
> >  #include "libavutil/channel_layout.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/float_dsp.h"
> > -#include "libavutil/internal.h"
> >  #include "avcodec.h"
> >  #include "bytestream.h"
> >  #include "fft.h"
> > diff --git a/libavcodec/opus.c b/libavcodec/opus.c
> > index f2b8ecc..47f2657 100644
> > --- a/libavcodec/opus.c
> > +++ b/libavcodec/opus.c
> > @@ -27,7 +27,7 @@
> >  #include <stdint.h>
> >
> >  #include "libavutil/error.h"
> > -#include "libavutil/internal.h"
> > +#include "libavutil/ffmath.h"
> >
> >  #include "opus.h"
> >  #include "vorbis.h"
> > diff --git a/libavcodec/wmadec.c b/libavcodec/wmadec.c
> > index 1a84323..7130bf6 100644
> > --- a/libavcodec/wmadec.c
> > +++ b/libavcodec/wmadec.c
> > @@ -34,8 +34,7 @@
> >   */
> >
> >  #include "libavutil/attributes.h"
> > -#include "libavutil/internal.h"
> > -#include "libavutil/libm.h"
> > +#include "libavutil/ffmath.h"
> >
> >  #include "avcodec.h"
> >  #include "internal.h"
> > diff --git a/libavcodec/wmaenc.c b/libavcodec/wmaenc.c
> > index d0727e6..418e958 100644
> > --- a/libavcodec/wmaenc.c
> > +++ b/libavcodec/wmaenc.c
> > @@ -20,7 +20,7 @@
> >   */
> >
> >  #include "libavutil/attributes.h"
> > -#include "libavutil/internal.h"
> > +#include "libavutil/ffmath.h"
> >
> >  #include "avcodec.h"
> >  #include "internal.h"
> > diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
> > index 2ea59e9..2cc1b09 100644
> > --- a/libavcodec/wmaprodec.c
> > +++ b/libavcodec/wmaprodec.c
> > @@ -88,8 +88,8 @@
> >
> >  #include <inttypes.h>
> >
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/float_dsp.h"
> > -#include "libavutil/internal.h"
> >  #include "libavutil/intfloat.h"
> >  #include "libavutil/intreadwrite.h"
> >  #include "avcodec.h"
> > diff --git a/libavfilter/af_anequalizer.c b/libavfilter/af_anequalizer.c
> > index a344c77..2403460 100644
> > --- a/libavfilter/af_anequalizer.c
> > +++ b/libavfilter/af_anequalizer.c
> > @@ -21,6 +21,7 @@
> >
> >  #include "libavutil/intreadwrite.h"
> >  #include "libavutil/avstring.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/opt.h"
> >  #include "libavutil/parseutils.h"
> >  #include "avfilter.h"
> > diff --git a/libavfilter/af_compand.c b/libavfilter/af_compand.c
> > index b746364..0bb719f 100644
> > --- a/libavfilter/af_compand.c
> > +++ b/libavfilter/af_compand.c
> > @@ -29,6 +29,7 @@
> >
> >  #include "libavutil/avassert.h"
> >  #include "libavutil/avstring.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/opt.h"
> >  #include "libavutil/samplefmt.h"
> >  #include "audio.h"
> > diff --git a/libavfilter/af_volume.c b/libavfilter/af_volume.c
> > index 3913e7b..4d6b916 100644
> > --- a/libavfilter/af_volume.c
> > +++ b/libavfilter/af_volume.c
> > @@ -27,6 +27,7 @@
> >  #include "libavutil/channel_layout.h"
> >  #include "libavutil/common.h"
> >  #include "libavutil/eval.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/float_dsp.h"
> >  #include "libavutil/intreadwrite.h"
> >  #include "libavutil/opt.h"
> > diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
> > index c4b30b4..59eaedd 100644
> > --- a/libavfilter/f_ebur128.c
> > +++ b/libavfilter/f_ebur128.c
> > @@ -33,6 +33,7 @@
> >  #include "libavutil/avstring.h"
> >  #include "libavutil/channel_layout.h"
> >  #include "libavutil/dict.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/xga_font_data.h"
> >  #include "libavutil/opt.h"
> >  #include "libavutil/timestamp.h"
> > diff --git a/libavfilter/vaf_spectrumsynth.c
> b/libavfilter/vaf_spectrumsynth.c
> > index 8d4014e..ee394b4 100644
> > --- a/libavfilter/vaf_spectrumsynth.c
> > +++ b/libavfilter/vaf_spectrumsynth.c
> > @@ -27,6 +27,7 @@
> >  #include "libavcodec/avfft.h"
> >  #include "libavutil/avassert.h"
> >  #include "libavutil/channel_layout.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/opt.h"
> >  #include "libavutil/parseutils.h"
> >  #include "avfilter.h"
> > diff --git a/libavfilter/vsrc_testsrc.c b/libavfilter/vsrc_testsrc.c
> > index a75dd4c..f0c0985 100644
> > --- a/libavfilter/vsrc_testsrc.c
> > +++ b/libavfilter/vsrc_testsrc.c
> > @@ -37,6 +37,7 @@
> >
> >  #include "libavutil/avassert.h"
> >  #include "libavutil/common.h"
> > +#include "libavutil/ffmath.h"
> >  #include "libavutil/opt.h"
> >  #include "libavutil/imgutils.h"
> >  #include "libavutil/intreadwrite.h"
> > diff --git a/libavutil/eval.c b/libavutil/eval.c
> > index 2acbbb4..37b8511 100644
> > --- a/libavutil/eval.c
> > +++ b/libavutil/eval.c
> > @@ -31,6 +31,7 @@
> >  #include "avutil.h"
> >  #include "common.h"
> >  #include "eval.h"
> > +#include "ffmath.h"
> >  #include "internal.h"
> >  #include "log.h"
> >  #include "mathematics.h"
> > diff --git a/libavutil/ffmath.h b/libavutil/ffmath.h
> > new file mode 100644
> > index 0000000..aad1347
> > --- /dev/null
> > +++ b/libavutil/ffmath.h
> > @@ -0,0 +1,67 @@
> > +/*
> > + * copyright (c) 2016 Ganesh Ajjanagadde <gajjanag at gmail.com>
> > + *
> > + * This file is part of FFmpeg.
> > + *
> > + * FFmpeg is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * FFmpeg is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with FFmpeg; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> > + */
> > +
> > +/**
> > + * @file
> > + * internal math functions header
> > + */
> > +
> > +#ifndef AVUTIL_FFMATH_H
> > +#define AVUTIL_FFMATH_H
> > +
> > +#include "attributes.h"
> > +#include "libm.h"
> > +
> > +/**
> > + * Compute 10^x for floating point values. Note: this function is by no
> means
> > + * "correctly rounded", and is meant as a fast, reasonably accurate
> approximation.
> > + * For instance, maximum relative error for the double precision
> variant is
> > + * ~ 1e-13 for very small and very large values.
> > + * This is ~2x faster than GNU libm's approach, which is still off by
> 2ulp on
> > + * some inputs.
> > + * @param x exponent
> > + * @return 10^x
> > + */
> > +static av_always_inline double ff_exp10(double x)
> > +{
> > +    return exp2(M_LOG2_10 * x);
> > +}
> > +
> > +static av_always_inline float ff_exp10f(float x)
> > +{
> > +    return exp2f(M_LOG2_10 * x);
> > +}
> > +
> > +/**
> > + * Compute x^y for floating point x, y. Note: this function is faster
> than the
> > + * libm variant due to mainly 2 reasons:
> > + * 1. It does not handle any edge cases. In particular, this is only
> guaranteed
> > + * to work correctly for x > 0.
> > + * 2. It is not as accurate as a standard nearly "correctly rounded"
> libm variant.
> > + * @param x base
> > + * @param y exponent
> > + * @return x^y
> > + */
> > +static av_always_inline float ff_fast_powf(float x, float y)
> > +{
> > +    return expf(logf(x) * y);
> > +}
> > +
> > +#endif /* AVUTIL_FFMATH_H */
> > diff --git a/libavutil/internal.h b/libavutil/internal.h
> > index 340e18b..61784b5 100644
> > --- a/libavutil/internal.h
> > +++ b/libavutil/internal.h
> > @@ -295,42 +295,6 @@ static av_always_inline av_const int64_t
> ff_rint64_clip(double a, int64_t amin,
> >  }
> >
> >  /**
> > - * Compute 10^x for floating point values. Note: this function is by no
> means
> > - * "correctly rounded", and is meant as a fast, reasonably accurate
> approximation.
> > - * For instance, maximum relative error for the double precision
> variant is
> > - * ~ 1e-13 for very small and very large values.
> > - * This is ~2x faster than GNU libm's approach, which is still off by
> 2ulp on
> > - * some inputs.
> > - * @param x exponent
> > - * @return 10^x
> > - */
> > -static av_always_inline double ff_exp10(double x)
> > -{
> > -    return exp2(M_LOG2_10 * x);
> > -}
> > -
> > -static av_always_inline float ff_exp10f(float x)
> > -{
> > -    return exp2f(M_LOG2_10 * x);
> > -}
> > -
> > -/**
> > - * Compute x^y for floating point x, y. Note: this function is faster
> than the
> > - * libm variant due to mainly 2 reasons:
> > - * 1. It does not handle any edge cases. In particular, this is only
> guaranteed
> > - * to work correctly for x > 0.
> > - * 2. It is not as accurate as a standard nearly "correctly rounded"
> libm variant.
> > - * @param x base
> > - * @param y exponent
> > - * @return x^y
> > - */
> > -static av_always_inline float ff_fast_powf(float x, float y)
> > -{
> > -    return expf(logf(x) * y);
> > -}
> > -
> > -
> > -/**
> >   * A wrapper for open() setting O_CLOEXEC.
> >   */
> >  av_warn_unused_result
> > --
> > 2.7.3
> >
>
> Ping, not sure if Ronald's comment counts as an ack on this. Thanks.


Yes it did, sorry for not being explicit about that: LGTM.

Ronald


More information about the ffmpeg-devel mailing list