Ensure that buffers returned by the default allocator are readable, or else
[libav.git] / libavfilter / defaults.c
1 /*
2 * Filter layer - default implementations
3 * copyright (c) 2007 Bobby Bingham
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "avfilter.h"
23
24 /* TODO: buffer pool. see comment for avfilter_default_get_video_buffer() */
25 void avfilter_default_free_video_buffer(AVFilterPic *pic)
26 {
27 avpicture_free((AVPicture *) pic);
28 av_free(pic);
29 }
30
31 /* TODO: set the buffer's priv member to a context structure for the whole
32 * filter chain. This will allow for a buffer pool instead of the constant
33 * alloc & free cycle currently implemented. */
34 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link, int perms)
35 {
36 AVFilterPic *pic = av_mallocz(sizeof(AVFilterPic));
37 AVFilterPicRef *ref = av_mallocz(sizeof(AVFilterPicRef));
38
39 ref->pic = pic;
40 ref->w = link->w;
41 ref->h = link->h;
42
43 /* make sure the buffer gets read permission or it's useless for output */
44 ref->perms = perms | AV_PERM_READ;
45
46 pic->refcount = 1;
47 pic->format = link->format;
48 pic->free = avfilter_default_free_video_buffer;
49 avpicture_alloc((AVPicture *)pic, pic->format, ref->w, ref->h);
50
51 memcpy(ref->data, pic->data, sizeof(pic->data));
52 memcpy(ref->linesize, pic->linesize, sizeof(pic->linesize));
53
54 return ref;
55 }
56
57 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref)
58 {
59 AVFilterLink *out = NULL;
60
61 if(link->dst->output_count)
62 out = link->dst->outputs[0];
63
64 if(out) {
65 out->outpic = avfilter_get_video_buffer(out, AV_PERM_WRITE);
66 out->outpic->pts = picref->pts;
67 avfilter_start_frame(out, avfilter_ref_pic(out->outpic, ~0));
68 }
69 }
70
71 void avfilter_default_end_frame(AVFilterLink *link)
72 {
73 AVFilterLink *out = NULL;
74
75 if(link->dst->output_count)
76 out = link->dst->outputs[0];
77
78 avfilter_unref_pic(link->cur_pic);
79 link->cur_pic = NULL;
80
81 if(out) {
82 if(out->outpic) {
83 avfilter_unref_pic(out->outpic);
84 out->outpic = NULL;
85 }
86 avfilter_end_frame(out);
87 }
88 }
89
90 /**
91 * default config_link() implementation for output video links to simplify
92 * the implementation of one input one output video filters */
93 int avfilter_default_config_output_link(AVFilterLink *link)
94 {
95 if(link->src->input_count && link->src->inputs[0]) {
96 link->w = link->src->inputs[0]->w;
97 link->h = link->src->inputs[0]->h;
98 } else {
99 /* XXX: any non-simple filter which would cause this branch to be taken
100 * really should implement its own config_props() for this link. */
101 link->w =
102 link->h = 0;
103 }
104
105 return 0;
106 }
107
108 /**
109 * default config_link() implementation for input video links to simplify
110 * the implementation of one input one output video filters */
111 int avfilter_default_config_input_link(AVFilterLink *link)
112 {
113 if(!link->dst->output_count)
114 return 0;
115 return avfilter_config_link(link->dst->outputs[0]);
116 }
117
118 /**
119 * default query_formats() implementation for output video links to simplify
120 * the implementation of one input one output video filters */
121 int *avfilter_default_query_output_formats(AVFilterLink *link)
122 {
123 if(link->src->input_count && link->src->inputs[0])
124 return avfilter_make_format_list(1, link->src->inputs[0]->format);
125 else
126 /* XXX: any non-simple filter which would cause this branch to be taken
127 * really should implement its own query_formats() for this link */
128 return avfilter_make_format_list(0);
129 }
130