[FFmpeg-devel] [PATCH 1/5] libavutil: Add fixed_dsp

Michael Niedermayer michaelni at gmx.at
Wed Apr 2 21:17:39 CEST 2014


On Wed, Apr 02, 2014 at 12:48:53AM -0300, James Almer wrote:
> On 01/04/14 11:31 AM, Nedeljko Babic wrote:
> > From: Nedeljko Babic <nbabic at mips.com>
> > 
> > Signed-off-by: Nedeljko Babic <nbabic at mips.com>
> > ---
> >  libavutil/Makefile    |   1 +
> >  libavutil/fixed_dsp.c |  98 ++++++++++++++++++++++++++++++++++
> >  libavutil/fixed_dsp.h | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  libavutil/version.h   |   2 +-
> >  4 files changed, 244 insertions(+), 1 deletion(-)
> >  create mode 100644 libavutil/fixed_dsp.c
> >  create mode 100644 libavutil/fixed_dsp.h
> > 
> > diff --git a/libavutil/Makefile b/libavutil/Makefile
> > index 2fe3e15..a90347c 100644
> > --- a/libavutil/Makefile
> > +++ b/libavutil/Makefile
> > @@ -89,6 +89,7 @@ OBJS = adler32.o                                                        \
> >         file.o                                                           \
> >         file_open.o                                                      \
> >         float_dsp.o                                                      \
> > +       fixed_dsp.o                                                      \
> >         frame.o                                                          \
> >         hash.o                                                           \
> >         hmac.o                                                           \
> > diff --git a/libavutil/fixed_dsp.c b/libavutil/fixed_dsp.c
> > new file mode 100644
> > index 0000000..6aceaac
> > --- /dev/null
> > +++ b/libavutil/fixed_dsp.c
> > @@ -0,0 +1,98 @@
> > +/*
> > + * Copyright (c) 2012
> > + *      MIPS Technologies, Inc., California.
> > + *
> > + * Redistribution and use in source and binary forms, with or without
> > + * modification, are permitted provided that the following conditions
> > + * are met:
> > + * 1. Redistributions of source code must retain the above copyright
> > + *    notice, this list of conditions and the following disclaimer.
> > + * 2. Redistributions in binary form must reproduce the above copyright
> > + *    notice, this list of conditions and the following disclaimer in the
> > + *    documentation and/or other materials provided with the distribution.
> > + * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
> > + *    contributors may be used to endorse or promote products derived from
> > + *    this software without specific prior written permission.
> > + *
> > + * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
> > + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> > + * ARE DISCLAIMED.  IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
> > + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> > + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> > + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> > + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> > + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> > + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> > + * SUCH DAMAGE.
> > + *
> > + * Author:  Nedeljko Babic (nbabic at mips.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
> > + */
> > +
> > +#include "fixed_dsp.h"
> > +
> > +static void vector_fmul_window_fixed_scaled_c(int16_t *dst, const int32_t *src0,
> > +                                       const int32_t *src1, const int32_t *win,
> > +                                       int len, uint8_t bits)
> > +{
> > +    int32_t s0, s1, wi, wj, i,j, round;
> > +
> > +    dst += len;
> > +    win += len;
> > +    src0+= len;
> > +    round = bits? 1 << (bits-1) : 0;
> > +
> > +    for (i=-len, j=len-1; i<0; i++, j--) {
> > +        s0 = src0[i];
> > +        s1 = src1[j];
> > +        wi = win[i];
> > +        wj = win[j];
> > +        dst[i] = av_clip_int16_c(((((int64_t)s0*wj - (int64_t)s1*wi + 0x40000000) >> 31) + round) >> bits);
> > +        dst[j] = av_clip_int16_c(((((int64_t)s0*wi + (int64_t)s1*wj + 0x40000000) >> 31) + round) >> bits);
> > +    }
> > +}
> > +
> > +static void vector_fmul_window_fixed_c(int32_t *dst, const int32_t *src0,
> > +                                       const int32_t *src1, const int32_t *win,
> > +                                       int len)
> > +{
> > +    int32_t s0, s1, wi, wj, i, j;
> > +
> > +    dst += len;
> > +    win += len;
> > +    src0+= len;
> > +
> > +    for (i=-len, j=len-1; i<0; i++, j--) {
> > +        s0 = src0[i];
> > +        s1 = src1[j];
> > +        wi = win[i];
> > +        wj = win[j];
> > +        dst[i] = ((int64_t)s0*wj - (int64_t)s1*wi + 0x40000000) >> 31;
> > +        dst[j] = ((int64_t)s0*wi + (int64_t)s1*wj + 0x40000000) >> 31;
> > +    }
> > +}
> > +
> > +AVFixedDSPContext * avpriv_alloc_fixed_dsp(int bit_exact)
> > +{
> > +    AVFixedDSPContext * fdsp = (AVFixedDSPContext*)av_malloc(sizeof(AVFixedDSPContext));
> > +    fdsp->vector_fmul_window_scaled = vector_fmul_window_fixed_scaled_c;
> > +    fdsp->vector_fmul_window = vector_fmul_window_fixed_c;
> > +
> > +    return fdsp;
> 
> I didn't catch this before, but why allocate the struct during init? Why not doing it the 
> same way as AVFloatDSPContext?
> Having the fixed and float versions so different is weird. And having to call av_free() is 
> annoying.

if theres no alloc, then any addition to the structure requires a
soname / major ABI bump

the float dsp is what is broken

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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