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/*

 * 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

 */

/**

 * @file

 * video crop filter

 */

#include 

#include "avfilter.h"

#include "formats.h"

#include "internal.h"

#include "video.h"

#include "libavutil/eval.h"

#include "libavutil/avstring.h"

#include "libavutil/internal.h"

#include "libavutil/libm.h"

#include "libavutil/imgutils.h"

#include "libavutil/mathematics.h"

#include "libavutil/opt.h"

static const char *const var_names[] = {

    "in_w", "iw",   ///< width  of the input video

    "in_h", "ih",   ///< height of the input video

    "out_w", "ow",  ///< width  of the cropped video

    "out_h", "oh",  ///< height of the cropped video

    "a",

    "sar",

    "dar",

    "hsub",

    "vsub",

    "x",

    "y",

    "n",            ///< number of frame

    "pos",          ///< position in the file

    "t",            ///< timestamp expressed in seconds

    NULL

};

enum var_name {

    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_X,

    VAR_Y,

    VAR_N,

    VAR_POS,

    VAR_T,

    VAR_VARS_NB

};

typedef struct {

    const AVClass *class;

    int  x;             ///< x offset of the non-cropped area with respect to the input area

    int  y;             ///< y offset of the non-cropped area with respect to the input area

    int  w;             ///< width of the cropped area

    int  h;             ///< height of the cropped area

    AVRational out_sar; ///< output sample aspect ratio

    int keep_aspect;    ///< keep display aspect ratio when cropping

    int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes

    int hsub, vsub;     ///< chroma subsampling

    char *x_expr, *y_expr, *w_expr, *h_expr;

    AVExpr *x_pexpr, *y_pexpr;  /* parsed expressions for x and y */

    double var_values[VAR_VARS_NB];

} CropContext;

static int query_formats(AVFilterContext *ctx)

{

    AVFilterFormats *formats = NULL;

    int fmt;

    for (fmt = 0; fmt < AV_PIX_FMT_NB; fmt++) {

        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);

        if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM)) &&

            !((desc->log2_chroma_w || desc->log2_chroma_h) && !(desc->flags & AV_PIX_FMT_FLAG_PLANAR)))

            ff_add_format(&formats, fmt);

    }

    ff_set_common_formats(ctx, formats);

    return 0;

}

static av_cold void uninit(AVFilterContext *ctx)

{

    CropContext *s = ctx->priv;

    av_expr_free(s->x_pexpr);

    s->x_pexpr = NULL;

    av_expr_free(s->y_pexpr);

    s->y_pexpr = NULL;

}

static inline int normalize_double(int *n, double d)

{

    int ret = 0;

    if (isnan(d)) {

        ret = AVERROR(EINVAL);

    } else if (d > INT_MAX || d < INT_MIN) {

        *n = d > INT_MAX ? INT_MAX : INT_MIN;

        ret = AVERROR(EINVAL);

    } else

        *n = round(d);

    return ret;

}

static int config_input(AVFilterLink *link)

{

    AVFilterContext *ctx = link->dst;

    CropContext *s = ctx->priv;

    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);

    int ret;

    const char *expr;

    double res;

    s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;

    s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;

    s->var_values[VAR_A]     = (float) link->w / link->h;

    s->var_values[VAR_SAR]   = link->sample_aspect_ratio.num ? av_q2d(link->sample_aspect_ratio) : 1;

    s->var_values[VAR_DAR]   = s->var_values[VAR_A] * s->var_values[VAR_SAR];

    s->var_values[VAR_HSUB]  = 1<log2_chroma_w;

    s->var_values[VAR_VSUB]  = 1<log2_chroma_h;

    s->var_values[VAR_X]     = NAN;

    s->var_values[VAR_Y]     = NAN;

    s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;

    s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;

    s->var_values[VAR_N]     = 0;

    s->var_values[VAR_T]     = NAN;

    s->var_values[VAR_POS]   = NAN;

    av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);

    s->hsub = pix_desc->log2_chroma_w;

    s->vsub = pix_desc->log2_chroma_h;

    if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),

                                      var_names, s->var_values,

                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        goto fail_expr;

    s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;

    if ((ret = av_expr_parse_and_eval(&res, (expr = s->h_expr),

                                      var_names, s->var_values,

                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        goto fail_expr;

    s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = res;

    /* evaluate again ow as it may depend on oh */

    if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),

                                      var_names, s->var_values,

                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        goto fail_expr;

    s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;

    if (normalize_double(&s->w, s->var_values[VAR_OUT_W]) < 0 ||

        normalize_double(&s->h, s->var_values[VAR_OUT_H]) < 0) {

        av_log(ctx, AV_LOG_ERROR,

               "Too big value or invalid expression for out_w/ow or out_h/oh. "

               "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",

               s->w_expr, s->h_expr);

        return AVERROR(EINVAL);

    }

    s->w &= ~((1 << s->hsub) - 1);

    s->h &= ~((1 << s->vsub) - 1);

    av_expr_free(s->x_pexpr);

    av_expr_free(s->y_pexpr);

    s->x_pexpr = s->y_pexpr = NULL;

    if ((ret = av_expr_parse(&s->x_pexpr, s->x_expr, var_names,

                             NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||

        (ret = av_expr_parse(&s->y_pexpr, s->y_expr, var_names,

                             NULL, NULL, NULL, NULL, 0, ctx)) < 0)

        return AVERROR(EINVAL);

    if (s->keep_aspect) {

        AVRational dar = av_mul_q(link->sample_aspect_ratio,

                                  (AVRational){ link->w, link->h });

        av_reduce(&s->out_sar.num, &s->out_sar.den,

                  dar.num * s->h, dar.den * s->w, INT_MAX);

    } else

        s->out_sar = link->sample_aspect_ratio;

    av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d sar:%d/%d -> w:%d h:%d sar:%d/%d\n",

           link->w, link->h, link->sample_aspect_ratio.num, link->sample_aspect_ratio.den,

           s->w, s->h, s->out_sar.num, s->out_sar.den);

    if (s->w <= 0 || s->h <= 0 ||

        s->w > link->w || s->h > link->h) {

        av_log(ctx, AV_LOG_ERROR,

               "Invalid too big or non positive size for width '%d' or height '%d'\n",

               s->w, s->h);

        return AVERROR(EINVAL);

    }

    /* set default, required in the case the first computed value for x/y is NAN */

    s->x = (link->w - s->w) / 2;

    s->y = (link->h - s->h) / 2;

    s->x &= ~((1 << s->hsub) - 1);

    s->y &= ~((1 << s->vsub) - 1);

    return 0;

fail_expr:

    av_log(NULL, AV_LOG_ERROR, "Error when evaluating the expression '%s'\n", expr);

    return ret;

}

static int config_output(AVFilterLink *link)

{

    CropContext *s = link->src->priv;

    link->w = s->w;

    link->h = s->h;

    link->sample_aspect_ratio = s->out_sar;

    return 0;

}

static int filter_frame(AVFilterLink *link, AVFrame *frame)

{

    AVFilterContext *ctx = link->dst;

    CropContext *s = ctx->priv;

    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);

    int i;

    frame->width  = s->w;

    frame->height = s->h;

    s->var_values[VAR_N] = link->frame_count;

    s->var_values[VAR_T] = frame->pts == AV_NOPTS_VALUE ?

        NAN : frame->pts * av_q2d(link->time_base);

    s->var_values[VAR_POS] = av_frame_get_pkt_pos(frame) == -1 ?

        NAN : av_frame_get_pkt_pos(frame);

    s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);

    s->var_values[VAR_Y] = av_expr_eval(s->y_pexpr, s->var_values, NULL);

    s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);

    normalize_double(&s->x, s->var_values[VAR_X]);

    normalize_double(&s->y, s->var_values[VAR_Y]);

    if (s->x < 0)

        s->x = 0;

    if (s->y < 0)

        s->y = 0;

    if ((unsigned)s->x + (unsigned)s->w > link->w)

        s->x = link->w - s->w;

    if ((unsigned)s->y + (unsigned)s->h > link->h)

        s->y = link->h - s->h;

    s->x &= ~((1 << s->hsub) - 1);

    s->y &= ~((1 << s->vsub) - 1);

    av_dlog(ctx, "n:%d t:%f pos:%f x:%d y:%d x+w:%d y+h:%d\n",

            (int)s->var_values[VAR_N], s->var_values[VAR_T], s->var_values[VAR_POS],

            s->x, s->y, s->x+s->w, s->y+s->h);

    frame->data[0] += s->y * frame->linesize[0];

    frame->data[0] += s->x * s->max_step[0];

    if (!(desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)) {

        for (i = 1; i < 3; i ++) {

            if (frame->data[i]) {

                frame->data[i] += (s->y >> s->vsub) * frame->linesize[i];

                frame->data[i] += (s->x * s->max_step[i]) >> s->hsub;

            }

        }

    }

    /* alpha plane */

    if (frame->data[3]) {

        frame->data[3] += s->y * frame->linesize[3];

        frame->data[3] += s->x * s->max_step[3];

    }

    return ff_filter_frame(link->dst->outputs[0], frame);

}

#define OFFSET(x) offsetof(CropContext, x)

#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

static const AVOption crop_options[] = {

    { "out_w",       "set the width crop area expression",   OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "w",           "set the width crop area expression",   OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "out_h",       "set the height crop area expression",  OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "h",           "set the height crop area expression",  OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "x",           "set the x crop area expression",       OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "(in_w-out_w)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "y",           "set the y crop area expression",       OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "(in_h-out_h)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },

    { "keep_aspect", "keep aspect ratio",                    OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },

    { NULL }

};

AVFILTER_DEFINE_CLASS(crop);

static const AVFilterPad avfilter_vf_crop_inputs[] = {

    {

        .name         = "default",

        .type         = AVMEDIA_TYPE_VIDEO,

        .filter_frame = filter_frame,

        .config_props = config_input,

    },

    { NULL }

};

static const AVFilterPad avfilter_vf_crop_outputs[] = {

    {

        .name         = "default",

        .type         = AVMEDIA_TYPE_VIDEO,

        .config_props = config_output,

    },

    { NULL }

};

AVFilter avfilter_vf_crop = {

    .name          = "crop",

    .description   = NULL_IF_CONFIG_SMALL("Crop the input video."),

    .priv_size     = sizeof(CropContext),

    .priv_class    = &crop_class,

    .query_formats = query_formats,

    .uninit        = uninit,

    .inputs        = avfilter_vf_crop_inputs,

    .outputs       = avfilter_vf_crop_outputs,

};