libavfilter/vf_zoompan.c
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 /*
  * Copyright (c) 2013 Paul B Mahol
  *
  * 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 "libavutil/eval.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 #include "libswscale/swscale.h"
 
 static const char *const var_names[] = {
     "in_w",   "iw",
     "in_h",   "ih",
     "out_w",  "ow",
     "out_h",  "oh",
     "in",
     "on",
     "duration",
     "pduration",
     "time",
     "frame",
     "zoom",
     "pzoom",
     "x", "px",
     "y", "py",
     "a",
     "sar",
     "dar",
     "hsub",
     "vsub",
     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_IN,
     VAR_ON,
     VAR_DURATION,
     VAR_PDURATION,
     VAR_TIME,
     VAR_FRAME,
     VAR_ZOOM,
     VAR_PZOOM,
     VAR_X, VAR_PX,
     VAR_Y, VAR_PY,
     VAR_A,
     VAR_SAR,
     VAR_DAR,
     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 
 typedef struct ZPcontext {
     const AVClass *class;
     char *zoom_expr_str;
     char *x_expr_str;
     char *y_expr_str;
     char *duration_expr_str;
     int w, h;
     double x, y;
     double prev_zoom;
     int prev_nb_frames;
     struct SwsContext *sws;
     int64_t frame_count;
 } ZPContext;
 
 #define OFFSET(x) offsetof(ZPContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 static const AVOption zoompan_options[] = {
     { "zoom", "set the zoom expression", OFFSET(zoom_expr_str), AV_OPT_TYPE_STRING, {.str = "1" }, .flags = FLAGS },
     { "z", "set the zoom expression", OFFSET(zoom_expr_str), AV_OPT_TYPE_STRING, {.str = "1" }, .flags = FLAGS },
     { "x", "set the x expression", OFFSET(x_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
     { "y", "set the y expression", OFFSET(y_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
     { "d", "set the duration expression", OFFSET(duration_expr_str), AV_OPT_TYPE_STRING, {.str="90"}, .flags = FLAGS },
     { "s", "set the output image size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="hd720"}, .flags = FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(zoompan);
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ZPContext *s = ctx->priv;
 
     s->prev_zoom = 1;
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ZPContext *s = ctx->priv;
 
     outlink->w = s->w;
     outlink->h = s->h;
 
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ZPContext *s = ctx->priv;
     double var_values[VARS_NB], nb_frames, zoom, dx, dy;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(in->format);
     AVFrame *out;
     int i, k, x, y, w, h, ret = 0;
 
     var_values[VAR_IN_W]  = var_values[VAR_IW] = in->width;
     var_values[VAR_IN_H]  = var_values[VAR_IH] = in->height;
     var_values[VAR_OUT_W] = var_values[VAR_OW] = s->w;
     var_values[VAR_OUT_H] = var_values[VAR_OH] = s->h;
     var_values[VAR_IN]    = inlink->frame_count + 1;
     var_values[VAR_ON]    = outlink->frame_count + 1;
     var_values[VAR_PX]    = s->x;
     var_values[VAR_PY]    = s->y;
     var_values[VAR_X]     = 0;
     var_values[VAR_Y]     = 0;
     var_values[VAR_PZOOM] = s->prev_zoom;
     var_values[VAR_ZOOM]  = 1;
     var_values[VAR_PDURATION] = s->prev_nb_frames;
     var_values[VAR_A]     = (double) in->width / in->height;
     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;
 
     if ((ret = av_expr_parse_and_eval(&nb_frames, s->duration_expr_str,
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto fail;
 
     var_values[VAR_DURATION] = nb_frames;
     for (i = 0; i < nb_frames; i++) {
         int px[4];
         int py[4];
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         uint8_t *input[4];
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         int64_t pts = av_rescale_q(in->pts, inlink->time_base,
                                    outlink->time_base) + s->frame_count;
 
         var_values[VAR_TIME] = pts * av_q2d(outlink->time_base);
         var_values[VAR_FRAME] = i;
         var_values[VAR_ON] = outlink->frame_count + 1;
         if ((ret = av_expr_parse_and_eval(&zoom, s->zoom_expr_str,
                                           var_names, var_values,
                                           NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
             goto fail;
 
         zoom = av_clipd(zoom, 1, 10);
         var_values[VAR_ZOOM] = zoom;
         w = in->width * (1.0 / zoom);
         h = in->height * (1.0 / zoom);
 
         if ((ret = av_expr_parse_and_eval(&dx, s->x_expr_str,
                                           var_names, var_values,
                                           NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
             goto fail;
         x = dx = av_clipd(dx, 0, FFMAX(in->width - w, 0));
         var_values[VAR_X] = dx;
         x &= ~((1 << desc->log2_chroma_w) - 1);
 
         if ((ret = av_expr_parse_and_eval(&dy, s->y_expr_str,
                                           var_names, var_values,
                                           NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
             goto fail;
         y = dy = av_clipd(dy, 0, FFMAX(in->height - h, 0));
         var_values[VAR_Y] = dy;
         y &= ~((1 << desc->log2_chroma_h) - 1);
 
         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
         if (!out) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
 
         px[1] = px[2] = FF_CEIL_RSHIFT(x, desc->log2_chroma_w);
         px[0] = px[3] = x;
 
         py[1] = py[2] = FF_CEIL_RSHIFT(y, desc->log2_chroma_h);
         py[0] = py[3] = y;
 
         s->sws = sws_alloc_context();
         if (!s->sws) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
 
         for (k = 0; in->data[k]; k++)
             input[k] = in->data[k] + py[k] * in->linesize[k] + px[k];
 
         av_opt_set_int(s->sws, "srcw", w, 0);
         av_opt_set_int(s->sws, "srch", h, 0);
         av_opt_set_int(s->sws, "src_format", in->format, 0);
         av_opt_set_int(s->sws, "dstw", outlink->w, 0);
         av_opt_set_int(s->sws, "dsth", outlink->h, 0);
         av_opt_set_int(s->sws, "dst_format", outlink->format, 0);
         av_opt_set_int(s->sws, "sws_flags", SWS_BICUBIC, 0);
 
         if ((ret = sws_init_context(s->sws, NULL, NULL)) < 0)
             goto fail;
 
         sws_scale(s->sws, (const uint8_t *const *)&input, in->linesize, 0, h, out->data, out->linesize);
 
         out->pts = pts;
         s->frame_count++;
 
         ret = ff_filter_frame(outlink, out);
         if (ret < 0)
             break;
 
         sws_freeContext(s->sws);
         s->sws = NULL;
     }
 
     s->x = dx;
     s->y = dy;
     s->prev_zoom = zoom;
     s->prev_nb_frames = nb_frames;
 
 fail:
     sws_freeContext(s->sws);
     s->sws = NULL;
     av_frame_free(&in);
     return ret;
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV410P,  AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P,
         AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ411P,
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_NONE
     };
 
 
     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ZPContext *s = ctx->priv;
 
     sws_freeContext(s->sws);
     s->sws = NULL;
 }
 
 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 AVFilter ff_vf_zoompan = {
     .name          = "zoompan",
     .description   = NULL_IF_CONFIG_SMALL("Apply Zoom & Pan effect."),
     .priv_size     = sizeof(ZPContext),
     .priv_class    = &zoompan_class,
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = inputs,
     .outputs       = outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };