vf_fade.c
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1 /*
2  * Copyright (c) 2010 Brandon Mintern
3  * Copyright (c) 2007 Bobby Bingham
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
28 #include "libavutil/common.h"
29 #include "libavutil/pixdesc.h"
30 #include "avfilter.h"
31 #include "formats.h"
32 #include "internal.h"
33 #include "video.h"
34 
35 typedef struct {
36  int factor, fade_per_frame;
37  unsigned int frame_index, start_frame, stop_frame;
38  int hsub, vsub, bpp;
39 } FadeContext;
40 
41 static av_cold int init(AVFilterContext *ctx, const char *args)
42 {
43  FadeContext *fade = ctx->priv;
44  unsigned int nb_frames;
45  char in_out[4];
46 
47  if (!args ||
48  sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
49  av_log(ctx, AV_LOG_ERROR,
50  "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
51  return AVERROR(EINVAL);
52  }
53 
54  nb_frames = nb_frames ? nb_frames : 1;
55  fade->fade_per_frame = (1 << 16) / nb_frames;
56  if (!strcmp(in_out, "in"))
57  fade->factor = 0;
58  else if (!strcmp(in_out, "out")) {
59  fade->fade_per_frame = -fade->fade_per_frame;
60  fade->factor = (1 << 16);
61  } else {
62  av_log(ctx, AV_LOG_ERROR,
63  "first argument must be 'in' or 'out':'%s'\n", in_out);
64  return AVERROR(EINVAL);
65  }
66  fade->stop_frame = fade->start_frame + nb_frames;
67 
69  "type:%s start_frame:%d nb_frames:%d\n",
70  in_out, fade->start_frame, nb_frames);
71  return 0;
72 }
73 
75 {
76  static const enum AVPixelFormat pix_fmts[] = {
83  };
84 
86  return 0;
87 }
88 
89 static int config_props(AVFilterLink *inlink)
90 {
91  FadeContext *fade = inlink->dst->priv;
92  const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
93 
94  fade->hsub = pixdesc->log2_chroma_w;
95  fade->vsub = pixdesc->log2_chroma_h;
96 
97  fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
98  return 0;
99 }
100 
101 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
102 {
103  FadeContext *fade = inlink->dst->priv;
104  uint8_t *p;
105  int i, j, plane;
106 
107  if (fade->factor < UINT16_MAX) {
108  /* luma or rgb plane */
109  for (i = 0; i < frame->video->h; i++) {
110  p = frame->data[0] + i * frame->linesize[0];
111  for (j = 0; j < inlink->w * fade->bpp; j++) {
112  /* fade->factor is using 16 lower-order bits for decimal
113  * places. 32768 = 1 << 15, it is an integer representation
114  * of 0.5 and is for rounding. */
115  *p = (*p * fade->factor + 32768) >> 16;
116  p++;
117  }
118  }
119 
120  if (frame->data[1] && frame->data[2]) {
121  /* chroma planes */
122  for (plane = 1; plane < 3; plane++) {
123  for (i = 0; i < frame->video->h; i++) {
124  p = frame->data[plane] + (i >> fade->vsub) * frame->linesize[plane];
125  for (j = 0; j < inlink->w >> fade->hsub; j++) {
126  /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
127  * representation of 128.5. The .5 is for rounding
128  * purposes. */
129  *p = ((*p - 128) * fade->factor + 8421367) >> 16;
130  p++;
131  }
132  }
133  }
134  }
135  }
136 
137  if (fade->frame_index >= fade->start_frame &&
138  fade->frame_index <= fade->stop_frame)
139  fade->factor += fade->fade_per_frame;
140  fade->factor = av_clip_uint16(fade->factor);
141  fade->frame_index++;
142 
143  return ff_filter_frame(inlink->dst->outputs[0], frame);
144 }
145 
147  {
148  .name = "default",
149  .type = AVMEDIA_TYPE_VIDEO,
150  .config_props = config_props,
151  .get_video_buffer = ff_null_get_video_buffer,
152  .filter_frame = filter_frame,
153  .min_perms = AV_PERM_READ | AV_PERM_WRITE,
154  .rej_perms = AV_PERM_PRESERVE,
155  },
156  { NULL }
157 };
158 
160  {
161  .name = "default",
162  .type = AVMEDIA_TYPE_VIDEO,
163  },
164  { NULL }
165 };
166 
168  .name = "fade",
169  .description = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
170  .init = init,
171  .priv_size = sizeof(FadeContext),
173 
174  .inputs = avfilter_vf_fade_inputs,
175  .outputs = avfilter_vf_fade_outputs,
176 };