libavfilter/vf_slicify.c

   1 /*
   2  * copyright (c) 2007 Bobby Bingham
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file libavfilter/vf_slicify.c
  23  * video slicing filter
  24  */
  25
  26 #include "avfilter.h"
  27
  28 typedef struct {
  29     int h;          ///< output slice height
  30     int vshift;     ///< vertical chroma subsampling shift
  31 } SliceContext;
  32
  33 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
  34 {
  35     SliceContext *slice = ctx->priv;
  36
  37     slice->h = 16;
  38     if (args)
  39         sscanf(args, "%d", &slice->h);
  40
  41     return 0;
  42 }
  43
  44 static int config_props(AVFilterLink *link)
  45 {
  46     SliceContext *slice = link->dst->priv;
  47     int tmp;
  48
  49     avcodec_get_chroma_sub_sample(link->format, &tmp, &slice->vshift);
  50
  51     /* ensure that slices play nice with chroma subsampling, and enforce
  52      * a reasonable minimum size for the slices */
  53     slice->h = FFMAX(8, slice->h & (-1 << slice->vshift));
  54
  55     av_log(link->dst, AV_LOG_INFO, "h:%d\n", slice->h);
  56
  57     return 0;
  58 }
  59
  60 static AVFilterPicRef *get_video_buffer(AVFilterLink *link, int perms,
  61                                         int w, int h)
  62 {
  63     return avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h);
  64 }
  65
  66 static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
  67 {
  68     avfilter_start_frame(link->dst->outputs[0], picref);
  69 }
  70
  71 static void end_frame(AVFilterLink *link)
  72 {
  73     avfilter_end_frame(link->dst->outputs[0]);
  74 }
  75
  76 static void draw_slice(AVFilterLink *link, int y, int h)
  77 {
  78     SliceContext *slice = link->dst->priv;
  79     int y2;
  80
  81     for (y2 = y; y2 + slice->h <= y + h; y2 += slice->h)
  82         avfilter_draw_slice(link->dst->outputs[0], y2, slice->h);
  83
  84     if (y2 < y + h)
  85         avfilter_draw_slice(link->dst->outputs[0], y2, y + h - y2);
  86 }
  87
  88 AVFilter avfilter_vf_slicify = {
  89     .name      = "slicify",
  90     .description = "Pass the images of input video on to next video filter as multiple slices.",
  91
  92     .init      = init,
  93
  94     .priv_size = sizeof(SliceContext),
  95
  96     .inputs    = (AVFilterPad[]) {{ .name             = "default",
  97                                     .type             = CODEC_TYPE_VIDEO,
  98                                     .get_video_buffer = get_video_buffer,
  99                                     .start_frame      = start_frame,
 100                                     .draw_slice       = draw_slice,
 101                                     .config_props     = config_props,
 102                                     .end_frame        = end_frame, },
 103                                   { .name = NULL}},
 104     .outputs   = (AVFilterPad[]) {{ .name            = "default",
 105                                     .type            = CODEC_TYPE_VIDEO, },
 106                                   { .name = NULL}},
 107 };