[FFmpeg-devel] [PATCH v3] avfilter/scale: refactor common code for scaling height/width expressions
Michael Niedermayer
michaelni at gmx.at
Sat Feb 4 01:04:34 EET 2017
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)
If you dont have coverity access, tell me and ill send you an invite
[...]
--
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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