/* * 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;     *ret_w = w;    *ret_h = h;     return 0; fail:    av_log(log_ctx, AV_LOG_ERROR,           "Error when evaluating the expression '%s'.\n"           "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",           expr, w_expr, h_expr);    return ret;}