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ffmpeg / libavfilter / vf_crop.c @ 4b3d0dc6

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/*
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 * copyright (c) 2007 Bobby Bingham
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * video crop filter
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 */
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#include "avfilter.h"
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#include "libavutil/eval.h"
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#include "libavutil/avstring.h"
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#include "libavutil/libm.h"
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#include "libavcore/imgutils.h"
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static const char *var_names[] = {
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    "E",
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    "PHI",
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    "PI",
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    "in_w", "iw",   ///< width  of the input video
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    "in_h", "ih",   ///< height of the input video
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    "out_w", "ow",  ///< width  of the cropped video
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    "out_h", "oh",  ///< height of the cropped video
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    "x",
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    "y",
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    "n",            ///< number of frame
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    "pos",          ///< position in the file
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    "t",            ///< timestamp expressed in seconds
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    NULL
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};
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enum var_name {
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    VAR_E,
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    VAR_PHI,
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    VAR_PI,
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    VAR_IN_W,  VAR_IW,
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    VAR_IN_H,  VAR_IH,
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    VAR_OUT_W, VAR_OW,
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    VAR_OUT_H, VAR_OH,
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    VAR_X,
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    VAR_Y,
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    VAR_N,
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    VAR_POS,
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    VAR_T,
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    VAR_VARS_NB
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};
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typedef struct {
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    int  x;             ///< x offset of the non-cropped area with respect to the input area
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    int  y;             ///< y offset of the non-cropped area with respect to the input area
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    int  w;             ///< width of the cropped area
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    int  h;             ///< height of the cropped area
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    int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes
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    int hsub, vsub;     ///< chroma subsampling
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    char x_expr[256], y_expr[256], ow_expr[256], oh_expr[256];
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    AVExpr *x_pexpr, *y_pexpr;  /* parsed expressions for x and y */
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    double var_values[VAR_VARS_NB];
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} CropContext;
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static int query_formats(AVFilterContext *ctx)
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{
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    static const enum PixelFormat pix_fmts[] = {
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        PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,
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        PIX_FMT_ARGB,         PIX_FMT_RGBA,
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        PIX_FMT_ABGR,         PIX_FMT_BGRA,
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        PIX_FMT_RGB24,        PIX_FMT_BGR24,
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        PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,
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        PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,
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        PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,
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        PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,
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        PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,
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        PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,
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        PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,
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        PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,
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        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
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        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
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        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
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        PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,
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        PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,
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        PIX_FMT_YUVA420P,
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        PIX_FMT_RGB8,         PIX_FMT_BGR8,
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        PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,
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        PIX_FMT_PAL8,         PIX_FMT_GRAY8,
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        PIX_FMT_NONE
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    };
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    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
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    return 0;
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}
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
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{
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    CropContext *crop = ctx->priv;
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    av_strlcpy(crop->ow_expr, "iw", sizeof(crop->ow_expr));
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    av_strlcpy(crop->oh_expr, "ih", sizeof(crop->oh_expr));
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    av_strlcpy(crop->x_expr, "(in_w-out_w)/2", sizeof(crop->x_expr));
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    av_strlcpy(crop->y_expr, "(in_h-out_h)/2", sizeof(crop->y_expr));
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    if (args)
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        sscanf(args, "%255[^:]:%255[^:]:%255[^:]:%255[^:]", crop->ow_expr, crop->oh_expr, crop->x_expr, crop->y_expr);
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    return 0;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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    CropContext *crop = ctx->priv;
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    av_free_expr(crop->x_pexpr); crop->x_pexpr = NULL;
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    av_free_expr(crop->y_pexpr); crop->y_pexpr = NULL;
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}
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static inline int normalize_double(int *n, double d)
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{
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    int ret = 0;
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    if (isnan(d)) {
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        ret = AVERROR(EINVAL);
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    } else if (d > INT_MAX || d < INT_MIN) {
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        *n = d > INT_MAX ? INT_MAX : INT_MIN;
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        ret = AVERROR(EINVAL);
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    } else
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        *n = round(d);
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    return ret;
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}
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static int config_input(AVFilterLink *link)
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{
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    AVFilterContext *ctx = link->dst;
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    CropContext *crop = ctx->priv;
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    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[link->format];
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    int ret;
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    const char *expr;
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    double res;
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    crop->var_values[VAR_E]     = M_E;
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    crop->var_values[VAR_PHI]   = M_PHI;
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    crop->var_values[VAR_PI]    = M_PI;
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    crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
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    crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;
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    crop->var_values[VAR_X]     = NAN;
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    crop->var_values[VAR_Y]     = NAN;
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    crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;
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    crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;
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    crop->var_values[VAR_N]     = 0;
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    crop->var_values[VAR_T]     = NAN;
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    crop->var_values[VAR_POS]   = NAN;
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    av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);
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    crop->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
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    crop->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
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    if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
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                                      var_names, crop->var_values,
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                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
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    crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
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    if ((ret = av_parse_and_eval_expr(&res, (expr = crop->oh_expr),
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                                      var_names, crop->var_values,
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                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
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    crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = res;
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    /* evaluate again ow as it may depend on oh */
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    if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
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                                      var_names, crop->var_values,
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                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
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    crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
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    if (normalize_double(&crop->w, crop->var_values[VAR_OUT_W]) < 0 ||
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        normalize_double(&crop->h, crop->var_values[VAR_OUT_H]) < 0) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Too big value or invalid expression for out_w/ow or out_h/oh. "
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               "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
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               crop->ow_expr, crop->oh_expr);
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        return AVERROR(EINVAL);
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    }
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    crop->w &= ~((1 << crop->hsub) - 1);
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    crop->h &= ~((1 << crop->vsub) - 1);
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    if ((ret = av_parse_expr(&crop->x_pexpr, crop->x_expr, var_names,
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                             NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
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        (ret = av_parse_expr(&crop->y_pexpr, crop->y_expr, var_names,
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                             NULL, NULL, NULL, NULL, 0, ctx)) < 0)
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        return AVERROR(EINVAL);
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    if (crop->w <= 0 || crop->h <= 0 ||
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        crop->w > link->w || crop->h > link->h) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Invalid too big or non positive size for width '%d' or height '%d'\n",
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               crop->w, crop->h);
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        return AVERROR(EINVAL);
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    }
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    /* set default, required in the case the first computed value for x/y is NAN */
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    crop->x = (link->w - crop->w) / 2;
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    crop->y = (link->h - crop->h) / 2;
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    crop->x &= ~((1 << crop->hsub) - 1);
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    crop->y &= ~((1 << crop->vsub) - 1);
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    return 0;
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fail_expr:
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    av_log(NULL, AV_LOG_ERROR, "Error when evaluating the expression '%s'\n", expr);
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    return ret;
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}
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static int config_output(AVFilterLink *link)
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{
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    CropContext *crop = link->src->priv;
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    link->w = crop->w;
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    link->h = crop->h;
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    return 0;
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}
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static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
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{
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    AVFilterContext *ctx = link->dst;
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    CropContext *crop = ctx->priv;
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    AVFilterBufferRef *ref2 = avfilter_ref_buffer(picref, ~0);
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    int i;
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    picref->video->w = crop->w;
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    picref->video->h = crop->h;
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    crop->var_values[VAR_T] = picref->pts == AV_NOPTS_VALUE ?
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        NAN : picref->pts * av_q2d(link->time_base);
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    crop->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
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    crop->var_values[VAR_X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
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    crop->var_values[VAR_Y] = av_eval_expr(crop->y_pexpr, crop->var_values, NULL);
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    crop->var_values[VAR_X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
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    normalize_double(&crop->x, crop->var_values[VAR_X]);
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    normalize_double(&crop->y, crop->var_values[VAR_Y]);
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    if (crop->x < 0) crop->x = 0;
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    if (crop->y < 0) crop->y = 0;
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    if ((unsigned)crop->x + (unsigned)crop->w > link->w) crop->x = link->w - crop->w;
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    if ((unsigned)crop->y + (unsigned)crop->h > link->h) crop->y = link->h - crop->h;
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    crop->x &= ~((1 << crop->hsub) - 1);
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    crop->y &= ~((1 << crop->vsub) - 1);
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    av_log(ctx, AV_LOG_DEBUG,
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           "n:%d t:%f x:%d y:%d x+w:%d y+h:%d\n",
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           (int)crop->var_values[VAR_N], crop->var_values[VAR_T], crop->x, crop->y, crop->x+crop->w, crop->y+crop->h);
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    ref2->data[0] += crop->y * ref2->linesize[0];
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    ref2->data[0] += crop->x * crop->max_step[0];
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    if (!(av_pix_fmt_descriptors[link->format].flags & PIX_FMT_PAL)) {
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        for (i = 1; i < 3; i ++) {
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            if (ref2->data[i]) {
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                ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i];
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                ref2->data[i] += (crop->x * crop->max_step[i]) >> crop->hsub;
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            }
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        }
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    }
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    /* alpha plane */
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    if (ref2->data[3]) {
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        ref2->data[3] += crop->y * ref2->linesize[3];
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        ref2->data[3] += crop->x * crop->max_step[3];
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    }
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    avfilter_start_frame(link->dst->outputs[0], ref2);
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}
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static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
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{
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    AVFilterContext *ctx = link->dst;
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    CropContext *crop = ctx->priv;
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    if (y >= crop->y + crop->h || y + h <= crop->y)
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        return;
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    if (y < crop->y) {
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        h -= crop->y - y;
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        y  = crop->y;
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    }
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    if (y + h > crop->y + crop->h)
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        h = crop->y + crop->h - y;
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    avfilter_draw_slice(ctx->outputs[0], y - crop->y, h, slice_dir);
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}
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static void end_frame(AVFilterLink *link)
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{
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    CropContext *crop = link->dst->priv;
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    crop->var_values[VAR_N] += 1.0;
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    avfilter_unref_buffer(link->cur_buf);
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    avfilter_end_frame(link->dst->outputs[0]);
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}
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AVFilter avfilter_vf_crop = {
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    .name      = "crop",
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    .description = NULL_IF_CONFIG_SMALL("Crop the input video to width:height:x:y."),
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    .priv_size = sizeof(CropContext),
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    .query_formats = query_formats,
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    .init          = init,
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    .uninit        = uninit,
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    .inputs    = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO,
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                                    .start_frame      = start_frame,
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                                    .draw_slice       = draw_slice,
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                                    .end_frame        = end_frame,
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                                    .get_video_buffer = avfilter_null_get_video_buffer,
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                                    .config_props     = config_input, },
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                                  { .name = NULL}},
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    .outputs   = (AVFilterPad[]) {{ .name             = "default",
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                                    .type             = AVMEDIA_TYPE_VIDEO,
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                                    .config_props     = config_output, },
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                                  { .name = NULL}},
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};