/* * 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 #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 }; /** * This must be kept in sync with var_names so that it is always a * complete list of var_names with the scale2ref specific names * appended. scale2ref values must appear in the order they appear * in the var_name_scale2ref enum but also be below all of the * non-scale2ref specific values. */ static const char *const var_names_scale2ref[] = { "PI", "PHI", "E", "in_w", "iw", "in_h", "ih", "out_w", "ow", "out_h", "oh", "a", "sar", "dar", "hsub", "vsub", "ohsub", "ovsub", "main_w", "main_h", "main_a", "main_sar", "main_dar", "mdar", "main_hsub", "main_vsub", NULL }; enum var_name_scale2ref { VAR_S2R_MAIN_W, VAR_S2R_MAIN_H, VAR_S2R_MAIN_A, VAR_S2R_MAIN_SAR, VAR_S2R_MAIN_DAR, VAR_S2R_MDAR, VAR_S2R_MAIN_HSUB, VAR_S2R_MAIN_VSUB, VARS_S2R_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; const char scale2ref = outlink->src->nb_inputs == 2 && outlink->src->inputs[1] == inlink; double var_values[VARS_NB + VARS_S2R_NB], res; const AVPixFmtDescriptor *main_desc; const AVFilterLink *main_link; const char *const *names = scale2ref ? var_names_scale2ref : var_names; if (scale2ref) { main_link = outlink->src->inputs[0]; main_desc = av_pix_fmt_desc_get(main_link->format); } 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; if (scale2ref) { var_values[VARS_NB + VAR_S2R_MAIN_W] = main_link->w; var_values[VARS_NB + VAR_S2R_MAIN_H] = main_link->h; var_values[VARS_NB + VAR_S2R_MAIN_A] = (double) main_link->w / main_link->h; var_values[VARS_NB + VAR_S2R_MAIN_SAR] = main_link->sample_aspect_ratio.num ? (double) main_link->sample_aspect_ratio.num / main_link->sample_aspect_ratio.den : 1; var_values[VARS_NB + VAR_S2R_MAIN_DAR] = var_values[VARS_NB + VAR_S2R_MDAR] = var_values[VARS_NB + VAR_S2R_MAIN_A] * var_values[VARS_NB + VAR_S2R_MAIN_SAR]; var_values[VARS_NB + VAR_S2R_MAIN_HSUB] = 1 << main_desc->log2_chroma_w; var_values[VARS_NB + VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h; } /* evaluate width and height */ av_expr_parse_and_eval(&res, (expr = w_expr), names, var_values, NULL, NULL, NULL, NULL, NULL, 0, log_ctx); eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res; if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr), 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] = (int) res == 0 ? inlink->h : (int) res; /* evaluate again the width, as it may depend on the output height */ if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr), names, var_values, NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0) goto fail; eval_w = (int) res == 0 ? inlink->w : (int) 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) { w = inlink->w; 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; }