Add pad filter.
[libav.git] / libavfilter / vf_slicify.c
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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/**
ba87f080 22 * @file
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23 * video slicing filter
24 */
25
26#include "avfilter.h"
b4b66456 27#include "libavutil/pixdesc.h"
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28
29typedef struct {
30 int h; ///< output slice height
31 int vshift; ///< vertical chroma subsampling shift
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32 uint32_t lcg_state; ///< LCG state used to compute random slice height
33 int use_random_h; ///< enable the use of random slice height values
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34} SliceContext;
35
36static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
37{
38 SliceContext *slice = ctx->priv;
39
40 slice->h = 16;
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41 if (args) {
42 if (!strcmp(args, "random")) {
43 slice->use_random_h = 1;
44 } else {
45 sscanf(args, "%d", &slice->h);
46 }
47 }
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48 return 0;
49}
50
51static int config_props(AVFilterLink *link)
52{
53 SliceContext *slice = link->dst->priv;
bc37ec92 54
b4b66456 55 slice->vshift = av_pix_fmt_descriptors[link->format].log2_chroma_h;
bc37ec92 56
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57 return 0;
58}
59
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60static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
61{
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62 SliceContext *slice = link->dst->priv;
63
64 if (slice->use_random_h) {
65 slice->lcg_state = slice->lcg_state * 1664525 + 1013904223;
66 slice->h = 8 + (uint64_t)slice->lcg_state * 25 / UINT32_MAX;
67 }
68
69 /* ensure that slices play nice with chroma subsampling, and enforce
70 * a reasonable minimum size for the slices */
71 slice->h = FFMAX(8, slice->h & (-1 << slice->vshift));
72
73 av_log(link->dst, AV_LOG_DEBUG, "h:%d\n", slice->h);
74
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75 avfilter_start_frame(link->dst->outputs[0], picref);
76}
77
a13a5437 78static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
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79{
80 SliceContext *slice = link->dst->priv;
81 int y2;
82
bf972d5e 83 if (slice_dir == 1) {
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84 for (y2 = y; y2 + slice->h <= y + h; y2 += slice->h)
85 avfilter_draw_slice(link->dst->outputs[0], y2, slice->h, slice_dir);
bc37ec92 86
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87 if (y2 < y + h)
88 avfilter_draw_slice(link->dst->outputs[0], y2, y + h - y2, slice_dir);
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89 } else if (slice_dir == -1) {
90 for (y2 = y + h; y2 - slice->h >= y; y2 -= slice->h)
91 avfilter_draw_slice(link->dst->outputs[0], y2 - slice->h, slice->h, slice_dir);
92
93 if (y2 > y)
94 avfilter_draw_slice(link->dst->outputs[0], y, y2 - y, slice_dir);
95 }
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96}
97
98AVFilter avfilter_vf_slicify = {
99 .name = "slicify",
100 .description = "Pass the images of input video on to next video filter as multiple slices.",
101
102 .init = init,
103
104 .priv_size = sizeof(SliceContext),
105
106 .inputs = (AVFilterPad[]) {{ .name = "default",
72415b2a 107 .type = AVMEDIA_TYPE_VIDEO,
d313e17a 108 .get_video_buffer = avfilter_null_get_video_buffer,
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109 .start_frame = start_frame,
110 .draw_slice = draw_slice,
111 .config_props = config_props,
d313e17a 112 .end_frame = avfilter_null_end_frame, },
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113 { .name = NULL}},
114 .outputs = (AVFilterPad[]) {{ .name = "default",
72415b2a 115 .type = AVMEDIA_TYPE_VIDEO, },
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116 { .name = NULL}},
117};