[FFmpeg-devel] [PATCH v3] avfilter/scale: refactor common code for scaling height/width expressions

Aman Gupta ffmpeg at tmm1.net
Sat Feb 4 20:04:07 EET 2017


On Fri, Feb 3, 2017 at 3:04 PM, Michael Niedermayer <michaelni at gmx.at>
wrote:

> On Wed, Feb 01, 2017 at 04:30:18PM -0800, Aman Gupta wrote:
> > From: Aman Gupta <aman at tmm1.net>
> >
> > Implements support for height/width expressions in vf_scale_vaapi,
> > by refactoring common code into a new libavfilter/scale.c
> > ---
> >  libavfilter/Makefile         |   8 +--
> >  libavfilter/scale.c          | 152 ++++++++++++++++++++++++++++++
> +++++++++++++
> >  libavfilter/scale.h          |  28 ++++++++
> >  libavfilter/vf_scale.c       | 109 +++----------------------------
> >  libavfilter/vf_scale_npp.c   |  93 +++-----------------------
> >  libavfilter/vf_scale_vaapi.c |  19 ++++--
> >  6 files changed, 216 insertions(+), 193 deletions(-)
> >  create mode 100644 libavfilter/scale.c
> >  create mode 100644 libavfilter/scale.h
> >
> > diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> > index 68a94be..3231f08 100644
> > --- a/libavfilter/Makefile
> > +++ b/libavfilter/Makefile
> > @@ -257,10 +257,10 @@ OBJS-$(CONFIG_REPEATFIELDS_FILTER)           +=
> vf_repeatfields.o
> >  OBJS-$(CONFIG_REVERSE_FILTER)                += f_reverse.o
> >  OBJS-$(CONFIG_ROTATE_FILTER)                 += vf_rotate.o
> >  OBJS-$(CONFIG_SAB_FILTER)                    += vf_sab.o
> > -OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o
> > -OBJS-$(CONFIG_SCALE_NPP_FILTER)              += vf_scale_npp.o
> > -OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o
> > -OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o
> > +OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o scale.o
> > +OBJS-$(CONFIG_SCALE_NPP_FILTER)              += vf_scale_npp.o scale.o
> > +OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o
> scale.o
> > +OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o scale.o
> >  OBJS-$(CONFIG_SELECT_FILTER)                 += f_select.o
> >  OBJS-$(CONFIG_SELECTIVECOLOR_FILTER)         += vf_selectivecolor.o
> >  OBJS-$(CONFIG_SENDCMD_FILTER)                += f_sendcmd.o
> > diff --git a/libavfilter/scale.c b/libavfilter/scale.c
> > new file mode 100644
> > index 0000000..50cd442
> > --- /dev/null
> > +++ b/libavfilter/scale.c
> > @@ -0,0 +1,152 @@
> > +/*
> > + * Copyright (c) 2007 Bobby Bingham
> > + *
> > + * 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 <stdint.h>
> > +#include "scale.h"
> > +#include "libavutil/eval.h"
> > +#include "libavutil/mathematics.h"
> > +#include "libavutil/pixdesc.h"
> > +
> > +static const char *const var_names[] = {
> > +    "PI",
> > +    "PHI",
> > +    "E",
> > +    "in_w",   "iw",
> > +    "in_h",   "ih",
> > +    "out_w",  "ow",
> > +    "out_h",  "oh",
> > +    "a",
> > +    "sar",
> > +    "dar",
> > +    "hsub",
> > +    "vsub",
> > +    "ohsub",
> > +    "ovsub",
> > +    NULL
> > +};
> > +
> > +enum var_name {
> > +    VAR_PI,
> > +    VAR_PHI,
> > +    VAR_E,
> > +    VAR_IN_W,   VAR_IW,
> > +    VAR_IN_H,   VAR_IH,
> > +    VAR_OUT_W,  VAR_OW,
> > +    VAR_OUT_H,  VAR_OH,
> > +    VAR_A,
> > +    VAR_SAR,
> > +    VAR_DAR,
> > +    VAR_HSUB,
> > +    VAR_VSUB,
> > +    VAR_OHSUB,
> > +    VAR_OVSUB,
> > +    VARS_NB
> > +};
> > +
> > +int ff_scale_eval_dimensions(void *log_ctx,
> > +    const char *w_expr, const char *h_expr,
> > +    AVFilterLink *inlink, AVFilterLink *outlink,
> > +    int *ret_w, int *ret_h)
> > +{
> > +    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->
> format);
> > +    const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->
> format);
> > +    const char *expr;
> > +    int w, h;
> > +    int factor_w, factor_h;
> > +    int eval_w, eval_h;
> > +    int ret;
> > +    double var_values[VARS_NB], res;
> > +
> > +    var_values[VAR_PI]    = M_PI;
> > +    var_values[VAR_PHI]   = M_PHI;
> > +    var_values[VAR_E]     = M_E;
> > +    var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
> > +    var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
> > +    var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
> > +    var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
> > +    var_values[VAR_A]     = (double) inlink->w / inlink->h;
> > +    var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
> > +        (double) inlink->sample_aspect_ratio.num /
> inlink->sample_aspect_ratio.den : 1;
> > +    var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
> > +    var_values[VAR_HSUB]  = 1 << desc->log2_chroma_w;
> > +    var_values[VAR_VSUB]  = 1 << desc->log2_chroma_h;
> > +    var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
> > +    var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
> > +
> > +    /* evaluate width and height */
> > +    av_expr_parse_and_eval(&res, (expr = w_expr),
> > +                           var_names, var_values,
> > +                           NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
> > +    eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
> > +
> > +    if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
> > +                                      var_names, var_values,
> > +                                      NULL, NULL, NULL, NULL, NULL, 0,
> log_ctx)) < 0)
> > +        goto fail;
> > +    eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
> > +    /* evaluate again the width, as it may depend on the output height
> */
> > +    if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
> > +                                      var_names, var_values,
> > +                                      NULL, NULL, NULL, NULL, NULL, 0,
> log_ctx)) < 0)
> > +        goto fail;
> > +    eval_w = res;
> > +
> > +    w = eval_w;
> > +    h = eval_h;
> > +
> > +    /* Check if it is requested that the result has to be divisible by
> a some
> > +     * factor (w or h = -n with n being the factor). */
> > +    factor_w = 1;
> > +    factor_h = 1;
> > +    if (w < -1) {
> > +        factor_w = -w;
> > +    }
> > +    if (h < -1) {
> > +        factor_h = -h;
> > +    }
> > +
> > +    if (w < 0 && h < 0)
> > +        eval_w = eval_h = 0;
> > +
> > +    if (!(w = eval_w))
> > +        w = inlink->w;
> > +    if (!(h = eval_h))
> > +        h = inlink->h;
> > +
>
> > +    /* Make sure that the result is divisible by the factor we
> determined
> > +     * earlier. If no factor was set, it is nothing will happen as the
> default
> > +     * factor is 1 */
> > +    if (w < 0)
> > +        w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;
> > +    if (h < 0)
> > +        h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;
>
> You changed w/h from 64bit to 32bit in this factorization
> is there anything that prevents overflows ?
>
> ALso the existing overflow checks are wrong after the 64->32bit
> change (CID 1399969)
>

Oops, I will change back to int64_t


>
> If you dont have coverity access, tell me and ill send you an invite
>

Please do.


>
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> it is not once nor twice but times without number that the same ideas make
> their appearance in the world. -- Aristotle
>
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