1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/*
* Copyright (c) 2012 Stefano Sabatini
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file framestep filter, inspired on libmpcodecs/vf_framestep.c by
* Daniele Fornighieri <guru AT digitalfantasy it>.
*/
#include "avfilter.h"
#include "internal.h"
#include "video.h"
typedef struct {
int frame_step, frame_count, frame_selected;
} FrameStepContext;
static av_cold int init(AVFilterContext *ctx, const char *args)
{
FrameStepContext *framestep = ctx->priv;
char *tailptr;
long int n = 1;
if (args) {
n = strtol(args, &tailptr, 10);
if (*tailptr || n <= 0 || n >= INT_MAX) {
av_log(ctx, AV_LOG_ERROR,
"Invalid argument '%s', must be a positive integer <= INT_MAX\n", args);
return AVERROR(EINVAL);
}
}
framestep->frame_step = n;
return 0;
}
static int config_output_props(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
FrameStepContext *framestep = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
outlink->frame_rate =
av_div_q(inlink->frame_rate, (AVRational){framestep->frame_step, 1});
av_log(ctx, AV_LOG_VERBOSE, "step:%d frame_rate:%d/%d(%f) -> frame_rate:%d/%d(%f)\n",
framestep->frame_step,
inlink->frame_rate.num, inlink->frame_rate.den, av_q2d(inlink->frame_rate),
outlink->frame_rate.num, outlink->frame_rate.den, av_q2d(outlink->frame_rate));
return 0;
}
static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *ref)
{
FrameStepContext *framestep = inlink->dst->priv;
framestep->frame_selected = 0;
if (!(framestep->frame_count++ % framestep->frame_step)) {
inlink->cur_buf = NULL;
framestep->frame_selected = 1;
return ff_start_frame(inlink->dst->outputs[0], ref);
}
return 0;
}
static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
{
FrameStepContext *framestep = inlink->dst->priv;
if (framestep->frame_selected)
return ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
return 0;
}
static int end_frame(AVFilterLink *inlink)
{
FrameStepContext *framestep = inlink->dst->priv;
if (framestep->frame_selected)
return ff_end_frame(inlink->dst->outputs[0]);
return 0;
}
static int request_frame(AVFilterLink *outlink)
{
FrameStepContext *framestep = outlink->src->priv;
AVFilterLink *inlink = outlink->src->inputs[0];
int ret;
framestep->frame_selected = 0;
do {
ret = ff_request_frame(inlink);
} while (!framestep->frame_selected && ret >= 0);
return ret;
}
static const AVFilterPad framestep_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.start_frame = start_frame,
.draw_slice = draw_slice,
.end_frame = end_frame,
},
{ NULL }
};
static const AVFilterPad framestep_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output_props,
.request_frame = request_frame,
},
{ NULL }
};
AVFilter avfilter_vf_framestep = {
.name = "framestep",
.description = NULL_IF_CONFIG_SMALL("Select one frame every N frames."),
.init = init,
.priv_size = sizeof(FrameStepContext),
.inputs = framestep_inputs,
.outputs = framestep_outputs,
};
|
