FFmpeg
vf_field.c
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1 /*
2  * Copyright (c) 2003 Rich Felker
3  * Copyright (c) 2012 Stefano Sabatini
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 /**
23  * @file
24  * field filter, based on libmpcodecs/vf_field.c by Rich Felker
25  */
26 
27 #include "libavutil/opt.h"
28 #include "libavutil/pixdesc.h"
29 #include "avfilter.h"
30 #include "internal.h"
31 
33 
34 typedef struct FieldContext {
35  const AVClass *class;
36  int type; ///< FieldType
37  int nb_planes; ///< number of planes of the current format
38 } FieldContext;
39 
40 #define OFFSET(x) offsetof(FieldContext, x)
41 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
42 
43 static const AVOption field_options[] = {
44  {"type", "set field type (top or bottom)", OFFSET(type), AV_OPT_TYPE_INT, {.i64=FIELD_TYPE_TOP}, 0, 1, FLAGS, "field_type" },
45  {"top", "select top field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_TOP}, INT_MIN, INT_MAX, FLAGS, "field_type"},
46  {"bottom", "select bottom field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "field_type"},
47  {NULL}
48 };
49 
51 
52 static int config_props_output(AVFilterLink *outlink)
53 {
54  AVFilterContext *ctx = outlink->src;
55  FieldContext *field = ctx->priv;
56  AVFilterLink *inlink = ctx->inputs[0];
57 
58  field->nb_planes = av_pix_fmt_count_planes(outlink->format);
59 
60  outlink->w = inlink->w;
61  outlink->h = (inlink->h + (field->type == FIELD_TYPE_TOP)) / 2;
62 
63  av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d type:%s -> w:%d h:%d\n",
64  inlink->w, inlink->h, field->type == FIELD_TYPE_BOTTOM ? "bottom" : "top",
65  outlink->w, outlink->h);
66  return 0;
67 }
68 
69 static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
70 {
71  FieldContext *field = inlink->dst->priv;
72  AVFilterLink *outlink = inlink->dst->outputs[0];
73  int i;
74 
75  inpicref->height = outlink->h;
76  inpicref->interlaced_frame = 0;
77 
78  for (i = 0; i < field->nb_planes; i++) {
79  if (field->type == FIELD_TYPE_BOTTOM)
80  inpicref->data[i] = inpicref->data[i] + inpicref->linesize[i];
81  inpicref->linesize[i] = 2 * inpicref->linesize[i];
82  }
83  return ff_filter_frame(outlink, inpicref);
84 }
85 
86 static const AVFilterPad field_inputs[] = {
87  {
88  .name = "default",
89  .type = AVMEDIA_TYPE_VIDEO,
90  .filter_frame = filter_frame,
91  },
92  { NULL }
93 };
94 
95 static const AVFilterPad field_outputs[] = {
96  {
97  .name = "default",
98  .type = AVMEDIA_TYPE_VIDEO,
99  .config_props = config_props_output,
100  },
101  { NULL }
102 };
103 
105  .name = "field",
106  .description = NULL_IF_CONFIG_SMALL("Extract a field from the input video."),
107  .priv_size = sizeof(FieldContext),
108  .inputs = field_inputs,
109  .outputs = field_outputs,
110  .priv_class = &field_class,
111 };
#define NULL
Definition: coverity.c:32
#define FLAGS
Definition: vf_field.c:41
static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
Definition: vf_field.c:69
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
static const AVFilterPad field_inputs[]
Definition: vf_field.c:86
AVOption.
Definition: opt.h:246
int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2562
Main libavfilter public API header.
GLint GLenum type
Definition: opengl_enc.c:104
#define OFFSET(x)
Definition: vf_field.c:40
const char * name
Pad name.
Definition: internal.h:60
static const AVOption field_options[]
Definition: vf_field.c:43
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:346
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1093
AVOptions.
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:192
int interlaced_frame
The content of the picture is interlaced.
Definition: frame.h:442
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:54
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this field
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void * priv
private data for use by the filter
Definition: avfilter.h:353
int type
FieldType.
Definition: vf_field.c:36
FieldType
Definition: vf_field.c:32
AVFormatContext * ctx
Definition: movenc.c:48
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
AVFILTER_DEFINE_CLASS(field)
static int config_props_output(AVFilterLink *outlink)
Definition: vf_field.c:52
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
int nb_planes
number of planes of the current format
Definition: vf_field.c:37
const char * name
Filter name.
Definition: avfilter.h:148
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
An instance of a filter.
Definition: avfilter.h:338
int height
Definition: frame.h:353
static const AVFilterPad field_outputs[]
Definition: vf_field.c:95
AVFilter ff_vf_field
Definition: vf_field.c:104
internal API functions