Libav
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/opt.h"
30 #include "libavutil/pixdesc.h"
31 #include "avfilter.h"
32 #include "formats.h"
33 #include "internal.h"
34 #include "video.h"
35 
36 #define FADE_IN 0
37 #define FADE_OUT 1
38 
39 typedef struct {
40  const AVClass *class;
41  int type;
42  int factor, fade_per_frame;
43  int start_frame, nb_frames;
44  unsigned int frame_index, stop_frame;
45  int hsub, vsub, bpp;
46 } FadeContext;
47 
48 static av_cold int init(AVFilterContext *ctx)
49 {
50  FadeContext *s = ctx->priv;
51 
52  s->fade_per_frame = (1 << 16) / s->nb_frames;
53  if (s->type == FADE_IN) {
54  s->factor = 0;
55  } else if (s->type == FADE_OUT) {
57  s->factor = (1 << 16);
58  }
59  s->stop_frame = s->start_frame + s->nb_frames;
60 
62  "type:%s start_frame:%d nb_frames:%d\n",
63  s->type == FADE_IN ? "in" : "out", s->start_frame,
64  s->nb_frames);
65  return 0;
66 }
67 
69 {
70  static const enum AVPixelFormat pix_fmts[] = {
77  };
78 
80  return 0;
81 }
82 
83 static int config_props(AVFilterLink *inlink)
84 {
85  FadeContext *s = inlink->dst->priv;
86  const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
87 
88  s->hsub = pixdesc->log2_chroma_w;
89  s->vsub = pixdesc->log2_chroma_h;
90 
91  s->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
92  return 0;
93 }
94 
95 static int filter_slice_luma(AVFilterContext *ctx, void *arg, int jobnr,
96  int nb_jobs)
97 {
98  FadeContext *s = ctx->priv;
99  AVFrame *frame = arg;
100  int slice_h = frame->height / nb_jobs;
101  int slice_start = jobnr * slice_h;
102  int slice_end = (jobnr == nb_jobs - 1) ? frame->height : (jobnr + 1) * slice_h;
103  int i, j;
104 
105  for (i = slice_start; i < slice_end; i++) {
106  uint8_t *p = frame->data[0] + i * frame->linesize[0];
107  for (j = 0; j < frame->width * s->bpp; j++) {
108  /* s->factor is using 16 lower-order bits for decimal
109  * places. 32768 = 1 << 15, it is an integer representation
110  * of 0.5 and is for rounding. */
111  *p = (*p * s->factor + 32768) >> 16;
112  p++;
113  }
114  }
115 
116  return 0;
117 }
118 
119 static int filter_slice_chroma(AVFilterContext *ctx, void *arg, int jobnr,
120  int nb_jobs)
121 {
122  FadeContext *s = ctx->priv;
123  AVFrame *frame = arg;
124  int slice_h = FFALIGN(frame->height / nb_jobs, 1 << s->vsub);
125  int slice_start = jobnr * slice_h;
126  int slice_end = (jobnr == nb_jobs - 1) ? frame->height : (jobnr + 1) * slice_h;
127  int i, j, plane;
128 
129  for (plane = 1; plane < 3; plane++) {
130  for (i = slice_start; i < slice_end; i++) {
131  uint8_t *p = frame->data[plane] + (i >> s->vsub) * frame->linesize[plane];
132  for (j = 0; j < frame->width >> s->hsub; j++) {
133  /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
134  * representation of 128.5. The .5 is for rounding
135  * purposes. */
136  *p = ((*p - 128) * s->factor + 8421367) >> 16;
137  p++;
138  }
139  }
140  }
141 
142  return 0;
143 }
144 
145 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
146 {
147  AVFilterContext *ctx = inlink->dst;
148  FadeContext *s = ctx->priv;
149 
150  if (s->factor < UINT16_MAX) {
151  /* luma or rgb plane */
152  ctx->internal->execute(ctx, filter_slice_luma, frame, NULL,
153  FFMIN(frame->height, ctx->graph->nb_threads));
154 
155  if (frame->data[1] && frame->data[2]) {
156  /* chroma planes */
157  ctx->internal->execute(ctx, filter_slice_chroma, frame, NULL,
158  FFMIN(frame->height, ctx->graph->nb_threads));
159  }
160  }
161 
162  if (s->frame_index >= s->start_frame &&
163  s->frame_index <= s->stop_frame)
164  s->factor += s->fade_per_frame;
165  s->factor = av_clip_uint16(s->factor);
166  s->frame_index++;
167 
168  return ff_filter_frame(inlink->dst->outputs[0], frame);
169 }
170 
171 #define OFFSET(x) offsetof(FadeContext, x)
172 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM
173 static const AVOption options[] = {
174  { "type", "'in' or 'out' for fade-in/fade-out", OFFSET(type), AV_OPT_TYPE_INT, { .i64 = FADE_IN }, FADE_IN, FADE_OUT, FLAGS, "type" },
175  { "in", "fade-in", 0, AV_OPT_TYPE_CONST, { .i64 = FADE_IN }, .unit = "type" },
176  { "out", "fade-out", 0, AV_OPT_TYPE_CONST, { .i64 = FADE_OUT }, .unit = "type" },
177  { "start_frame", "Number of the first frame to which to apply the effect.",
178  OFFSET(start_frame), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
179  { "nb_frames", "Number of frames to which the effect should be applied.",
180  OFFSET(nb_frames), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, INT_MAX, FLAGS },
181  { NULL },
182 };
183 
184 static const AVClass fade_class = {
185  .class_name = "fade",
186  .item_name = av_default_item_name,
187  .option = options,
188  .version = LIBAVUTIL_VERSION_INT,
189 };
190 
192  {
193  .name = "default",
194  .type = AVMEDIA_TYPE_VIDEO,
195  .config_props = config_props,
196  .get_video_buffer = ff_null_get_video_buffer,
197  .filter_frame = filter_frame,
198  .needs_writable = 1,
199  },
200  { NULL }
201 };
202 
204  {
205  .name = "default",
206  .type = AVMEDIA_TYPE_VIDEO,
207  },
208  { NULL }
209 };
210 
212  .name = "fade",
213  .description = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
214  .init = init,
215  .priv_size = sizeof(FadeContext),
216  .priv_class = &fade_class,
218 
219  .inputs = avfilter_vf_fade_inputs,
220  .outputs = avfilter_vf_fade_outputs,
222 };