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libavfilter/vf_cropdetect.c

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00001 /*
00002  * Copyright (c) 2002 A'rpi
00003  * This file is part of FFmpeg.
00004  *
00005  * FFmpeg is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License as published by
00007  * the Free Software Foundation; either version 2 of the License, or
00008  * (at your option) any later version.
00009  *
00010  * FFmpeg is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  * GNU General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU General Public License along
00016  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
00017  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00018  */
00019 
00026 #include "libavutil/imgutils.h"
00027 #include "avfilter.h"
00028 
00029 typedef struct {
00030     int x1, y1, x2, y2;
00031     int limit;
00032     int round;
00033     int reset_count;
00034     int frame_nb;
00035     int max_pixsteps[4];
00036 } CropDetectContext;
00037 
00038 static int query_formats(AVFilterContext *ctx)
00039 {
00040     static const enum PixelFormat pix_fmts[] = {
00041         PIX_FMT_YUV420P, PIX_FMT_YUVJ420P,
00042         PIX_FMT_YUV422P, PIX_FMT_YUVJ422P,
00043         PIX_FMT_YUV444P, PIX_FMT_YUVJ444P,
00044         PIX_FMT_YUV411P, PIX_FMT_GRAY8,
00045         PIX_FMT_NV12,    PIX_FMT_NV21,
00046         PIX_FMT_NONE
00047     };
00048 
00049     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
00050     return 0;
00051 }
00052 
00053 static int checkline(void *ctx, const unsigned char *src, int stride, int len, int bpp)
00054 {
00055     int total = 0;
00056     int div = len;
00057 
00058     switch (bpp) {
00059     case 1:
00060         while (--len >= 0) {
00061             total += src[0];
00062             src += stride;
00063         }
00064         break;
00065     case 3:
00066     case 4:
00067         while (--len >= 0) {
00068             total += src[0] + src[1] + src[2];
00069             src += stride;
00070         }
00071         div *= 3;
00072         break;
00073     }
00074     total /= div;
00075 
00076     av_log(ctx, AV_LOG_DEBUG, "total:%d\n", total);
00077     return total;
00078 }
00079 
00080 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
00081 {
00082     CropDetectContext *cd = ctx->priv;
00083 
00084     cd->limit = 24;
00085     cd->round = 0;
00086     cd->reset_count = 0;
00087     cd->frame_nb = -2;
00088 
00089     if (args)
00090         sscanf(args, "%d:%d:%d", &cd->limit, &cd->round, &cd->reset_count);
00091 
00092     av_log(ctx, AV_LOG_INFO, "limit:%d round:%d reset_count:%d\n",
00093            cd->limit, cd->round, cd->reset_count);
00094 
00095     return 0;
00096 }
00097 
00098 static int config_input(AVFilterLink *inlink)
00099 {
00100     AVFilterContext *ctx = inlink->dst;
00101     CropDetectContext *cd = ctx->priv;
00102 
00103     av_image_fill_max_pixsteps(cd->max_pixsteps, NULL,
00104                                &av_pix_fmt_descriptors[inlink->format]);
00105 
00106     cd->x1 = inlink->w - 1;
00107     cd->y1 = inlink->h - 1;
00108     cd->x2 = 0;
00109     cd->y2 = 0;
00110 
00111     return 0;
00112 }
00113 
00114 static void end_frame(AVFilterLink *inlink)
00115 {
00116     AVFilterContext *ctx = inlink->dst;
00117     CropDetectContext *cd = ctx->priv;
00118     AVFilterBufferRef *picref = inlink->cur_buf;
00119     int bpp = cd->max_pixsteps[0];
00120     int w, h, x, y, shrink_by;
00121 
00122     // ignore first 2 frames - they may be empty
00123     if (++cd->frame_nb > 0) {
00124         // Reset the crop area every reset_count frames, if reset_count is > 0
00125         if (cd->reset_count > 0 && cd->frame_nb > cd->reset_count) {
00126             cd->x1 = picref->video->w-1;
00127             cd->y1 = picref->video->h-1;
00128             cd->x2 = 0;
00129             cd->y2 = 0;
00130             cd->frame_nb = 1;
00131         }
00132 
00133         for (y = 0; y < cd->y1; y++) {
00134             if (checkline(ctx, picref->data[0] + picref->linesize[0] * y, bpp, picref->video->w, bpp) > cd->limit) {
00135                 cd->y1 = y;
00136                 break;
00137             }
00138         }
00139 
00140         for (y = picref->video->h-1; y > cd->y2; y--) {
00141             if (checkline(ctx, picref->data[0] + picref->linesize[0] * y, bpp, picref->video->w, bpp) > cd->limit) {
00142                 cd->y2 = y;
00143                 break;
00144             }
00145         }
00146 
00147         for (y = 0; y < cd->x1; y++) {
00148             if (checkline(ctx, picref->data[0] + bpp*y, picref->linesize[0], picref->video->h, bpp) > cd->limit) {
00149                 cd->x1 = y;
00150                 break;
00151             }
00152         }
00153 
00154         for (y = picref->video->w-1; y > cd->x2; y--) {
00155             if (checkline(ctx, picref->data[0] + bpp*y, picref->linesize[0], picref->video->h, bpp) > cd->limit) {
00156                 cd->x2 = y;
00157                 break;
00158             }
00159         }
00160 
00161         // round x and y (up), important for yuv colorspaces
00162         // make sure they stay rounded!
00163         x = (cd->x1+1) & ~1;
00164         y = (cd->y1+1) & ~1;
00165 
00166         w = cd->x2 - x + 1;
00167         h = cd->y2 - y + 1;
00168 
00169         // w and h must be divisible by 2 as well because of yuv
00170         // colorspace problems.
00171         if (cd->round <= 1)
00172             cd->round = 16;
00173         if (cd->round % 2)
00174             cd->round *= 2;
00175 
00176         shrink_by = w % cd->round;
00177         w -= shrink_by;
00178         x += (shrink_by/2 + 1) & ~1;
00179 
00180         shrink_by = h % cd->round;
00181         h -= shrink_by;
00182         y += (shrink_by/2 + 1) & ~1;
00183 
00184         av_log(ctx, AV_LOG_INFO,
00185                "x1:%d x2:%d y1:%d y2:%d w:%d h:%d x:%d y:%d pos:%"PRId64" pts:%"PRId64" t:%f crop=%d:%d:%d:%d\n",
00186                cd->x1, cd->x2, cd->y1, cd->y2, w, h, x, y, picref->pos, picref->pts,
00187                picref->pts == AV_NOPTS_VALUE ? -1 : picref->pts * av_q2d(inlink->time_base),
00188                w, h, x, y);
00189     }
00190 
00191     avfilter_end_frame(inlink->dst->outputs[0]);
00192 }
00193 
00194 AVFilter avfilter_vf_cropdetect = {
00195     .name        = "cropdetect",
00196     .description = NULL_IF_CONFIG_SMALL("Auto-detect crop size."),
00197 
00198     .priv_size = sizeof(CropDetectContext),
00199     .init      = init,
00200 
00201     .query_formats = query_formats,
00202 
00203     .inputs    = (const AVFilterPad[]) {{ .name       = "default",
00204                                     .type             = AVMEDIA_TYPE_VIDEO,
00205                                     .config_props     = config_input,
00206                                     .get_video_buffer = avfilter_null_get_video_buffer,
00207                                     .start_frame      = avfilter_null_start_frame,
00208                                     .end_frame        = end_frame, },
00209                                   { .name = NULL}},
00210 
00211     .outputs   = (const AVFilterPad[]) {{ .name       = "default",
00212                                     .type             = AVMEDIA_TYPE_VIDEO },
00213                                   { .name = NULL}},
00214 };
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