More accurate value for log2(10)
[libav.git] / 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 #include "libavutil/pixdesc.h"
28
29 typedef struct {
30 int h; ///< output slice height
31 int vshift; ///< vertical chroma subsampling shift
32 } SliceContext;
33
34 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
35 {
36 SliceContext *slice = ctx->priv;
37
38 slice->h = 16;
39 if (args)
40 sscanf(args, "%d", &slice->h);
41
42 return 0;
43 }
44
45 static int config_props(AVFilterLink *link)
46 {
47 SliceContext *slice = link->dst->priv;
48
49 slice->vshift = av_pix_fmt_descriptors[link->format].log2_chroma_h;
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, int slice_dir)
77 {
78 SliceContext *slice = link->dst->priv;
79 int y2;
80
81 if (slice_dir == 1) {
82 for (y2 = y; y2 + slice->h <= y + h; y2 += slice->h)
83 avfilter_draw_slice(link->dst->outputs[0], y2, slice->h, slice_dir);
84
85 if (y2 < y + h)
86 avfilter_draw_slice(link->dst->outputs[0], y2, y + h - y2, slice_dir);
87 } else if (slice_dir == -1) {
88 for (y2 = y + h; y2 - slice->h >= y; y2 -= slice->h)
89 avfilter_draw_slice(link->dst->outputs[0], y2 - slice->h, slice->h, slice_dir);
90
91 if (y2 > y)
92 avfilter_draw_slice(link->dst->outputs[0], y, y2 - y, slice_dir);
93 }
94 }
95
96 AVFilter avfilter_vf_slicify = {
97 .name = "slicify",
98 .description = "Pass the images of input video on to next video filter as multiple slices.",
99
100 .init = init,
101
102 .priv_size = sizeof(SliceContext),
103
104 .inputs = (AVFilterPad[]) {{ .name = "default",
105 .type = CODEC_TYPE_VIDEO,
106 .get_video_buffer = get_video_buffer,
107 .start_frame = start_frame,
108 .draw_slice = draw_slice,
109 .config_props = config_props,
110 .end_frame = end_frame, },
111 { .name = NULL}},
112 .outputs = (AVFilterPad[]) {{ .name = "default",
113 .type = CODEC_TYPE_VIDEO, },
114 { .name = NULL}},
115 };