vf_overlay.c
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1 /*
2  * Copyright (c) 2010 Stefano Sabatini
3  * Copyright (c) 2010 Baptiste Coudurier
4  * Copyright (c) 2007 Bobby Bingham
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
28 #include "avfilter.h"
29 #include "libavutil/eval.h"
30 #include "libavutil/avstring.h"
31 #include "libavutil/pixdesc.h"
32 #include "libavutil/imgutils.h"
33 #include "libavutil/mathematics.h"
34 #include "internal.h"
35 
36 static const char *var_names[] = {
37  "E",
38  "PHI",
39  "PI",
40  "main_w", "W",
41  "main_h", "H",
42  "overlay_w", "w",
43  "overlay_h", "h",
44  NULL
45 };
46 
47 enum var_name {
56 };
57 
58 #define MAIN 0
59 #define OVERLAY 1
60 
61 typedef struct {
62  int x, y;
63 
65 
66  int max_plane_step[4];
67  int hsub, vsub;
68 
69  char x_expr[256], y_expr[256];
71 
72 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
73 {
74  OverlayContext *over = ctx->priv;
75 
76  av_strlcpy(over->x_expr, "0", sizeof(over->x_expr));
77  av_strlcpy(over->y_expr, "0", sizeof(over->y_expr));
78 
79  if (args)
80  sscanf(args, "%255[^:]:%255[^:]", over->x_expr, over->y_expr);
81 
82  return 0;
83 }
84 
85 static av_cold void uninit(AVFilterContext *ctx)
86 {
87  OverlayContext *over = ctx->priv;
88 
89  if (over->overpicref)
91 }
92 
94 {
95  const enum PixelFormat inout_pix_fmts[] = { PIX_FMT_YUV420P, PIX_FMT_NONE };
96  const enum PixelFormat blend_pix_fmts[] = { PIX_FMT_YUVA420P, PIX_FMT_NONE };
97  AVFilterFormats *inout_formats = avfilter_make_format_list(inout_pix_fmts);
98  AVFilterFormats *blend_formats = avfilter_make_format_list(blend_pix_fmts);
99 
100  avfilter_formats_ref(inout_formats, &ctx->inputs [MAIN ]->out_formats);
101  avfilter_formats_ref(blend_formats, &ctx->inputs [OVERLAY]->out_formats);
102  avfilter_formats_ref(inout_formats, &ctx->outputs[MAIN ]->in_formats );
103 
104  return 0;
105 }
106 
107 static int config_input_main(AVFilterLink *inlink)
108 {
109  OverlayContext *over = inlink->dst->priv;
110  const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
111 
113  over->hsub = pix_desc->log2_chroma_w;
114  over->vsub = pix_desc->log2_chroma_h;
115 
116  return 0;
117 }
118 
120 {
121  AVFilterContext *ctx = inlink->dst;
122  OverlayContext *over = inlink->dst->priv;
123  char *expr;
124  double var_values[VAR_VARS_NB], res;
125  int ret;
126 
127  /* Finish the configuration by evaluating the expressions
128  now when both inputs are configured. */
129  var_values[VAR_E ] = M_E;
130  var_values[VAR_PHI] = M_PHI;
131  var_values[VAR_PI ] = M_PI;
132 
133  var_values[VAR_MAIN_W ] = var_values[VAR_MW] = ctx->inputs[MAIN ]->w;
134  var_values[VAR_MAIN_H ] = var_values[VAR_MH] = ctx->inputs[MAIN ]->h;
135  var_values[VAR_OVERLAY_W] = var_values[VAR_OW] = ctx->inputs[OVERLAY]->w;
136  var_values[VAR_OVERLAY_H] = var_values[VAR_OH] = ctx->inputs[OVERLAY]->h;
137 
138  if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
139  NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
140  goto fail;
141  over->x = res;
142  if ((ret = av_expr_parse_and_eval(&res, (expr = over->y_expr), var_names, var_values,
143  NULL, NULL, NULL, NULL, NULL, 0, ctx)))
144  goto fail;
145  over->y = res;
146  /* x may depend on y */
147  if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
148  NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
149  goto fail;
150  over->x = res;
151 
152  av_log(ctx, AV_LOG_INFO,
153  "main w:%d h:%d fmt:%s overlay x:%d y:%d w:%d h:%d fmt:%s\n",
154  ctx->inputs[MAIN]->w, ctx->inputs[MAIN]->h,
156  over->x, over->y,
157  ctx->inputs[OVERLAY]->w, ctx->inputs[OVERLAY]->h,
159 
160  if (over->x < 0 || over->y < 0 ||
161  over->x + var_values[VAR_OVERLAY_W] > var_values[VAR_MAIN_W] ||
162  over->y + var_values[VAR_OVERLAY_H] > var_values[VAR_MAIN_H]) {
163  av_log(ctx, AV_LOG_ERROR,
164  "Overlay area (%d,%d)<->(%d,%d) not within the main area (0,0)<->(%d,%d) or zero-sized\n",
165  over->x, over->y,
166  (int)(over->x + var_values[VAR_OVERLAY_W]),
167  (int)(over->y + var_values[VAR_OVERLAY_H]),
168  (int)var_values[VAR_MAIN_W], (int)var_values[VAR_MAIN_H]);
169  return AVERROR(EINVAL);
170  }
171  return 0;
172 
173 fail:
175  "Error when evaluating the expression '%s'\n", expr);
176  return ret;
177 }
178 
179 static int config_output(AVFilterLink *outlink)
180 {
181  AVFilterContext *ctx = outlink->src;
182  int exact;
183  // common timebase computation:
184  AVRational tb1 = ctx->inputs[MAIN ]->time_base;
185  AVRational tb2 = ctx->inputs[OVERLAY]->time_base;
186  AVRational *tb = &ctx->outputs[0]->time_base;
187  exact = av_reduce(&tb->num, &tb->den,
188  av_gcd((int64_t)tb1.num * tb2.den,
189  (int64_t)tb2.num * tb1.den),
190  (int64_t)tb1.den * tb2.den, INT_MAX);
191  av_log(ctx, AV_LOG_INFO,
192  "main_tb:%d/%d overlay_tb:%d/%d -> tb:%d/%d exact:%d\n",
193  tb1.num, tb1.den, tb2.num, tb2.den, tb->num, tb->den, exact);
194  if (!exact)
195  av_log(ctx, AV_LOG_WARNING,
196  "Timestamp conversion inexact, timestamp information loss may occurr\n");
197 
198  outlink->w = ctx->inputs[MAIN]->w;
199  outlink->h = ctx->inputs[MAIN]->h;
200 
201  return 0;
202 }
203 
204 static AVFilterBufferRef *get_video_buffer(AVFilterLink *link, int perms, int w, int h)
205 {
206  return avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h);
207 }
208 
209 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
210 {
211  AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
212  AVFilterContext *ctx = inlink->dst;
213  OverlayContext *over = ctx->priv;
214 
215  inlink->dst->outputs[0]->out_buf = outpicref;
216  outpicref->pts = av_rescale_q(outpicref->pts, ctx->inputs[MAIN]->time_base,
217  ctx->outputs[0]->time_base);
218 
219  if (!over->overpicref || over->overpicref->pts < outpicref->pts) {
220  AVFilterBufferRef *old = over->overpicref;
221  over->overpicref = NULL;
223  if (over->overpicref) {
224  if (old)
226  } else
227  over->overpicref = old;
228  }
229 
230  avfilter_start_frame(inlink->dst->outputs[0], outpicref);
231 }
232 
233 static void start_frame_overlay(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
234 {
235  AVFilterContext *ctx = inlink->dst;
236  OverlayContext *over = ctx->priv;
237 
238  over->overpicref = inpicref;
239  over->overpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[OVERLAY]->time_base,
240  ctx->outputs[0]->time_base);
241 }
242 
243 static void blend_slice(AVFilterContext *ctx,
245  int x, int y, int w, int h,
246  int slice_y, int slice_w, int slice_h)
247 {
248  OverlayContext *over = ctx->priv;
249  int i, j, k;
250  int width, height;
251  int overlay_end_y = y+h;
252  int slice_end_y = slice_y+slice_h;
253  int end_y, start_y;
254 
255  width = FFMIN(slice_w - x, w);
256  end_y = FFMIN(slice_end_y, overlay_end_y);
257  start_y = FFMAX(y, slice_y);
258  height = end_y - start_y;
259 
260  if (dst->format == PIX_FMT_BGR24 || dst->format == PIX_FMT_RGB24) {
261  uint8_t *dp = dst->data[0] + x * 3 + start_y * dst->linesize[0];
262  uint8_t *sp = src->data[0];
263  int b = dst->format == PIX_FMT_BGR24 ? 2 : 0;
264  int r = dst->format == PIX_FMT_BGR24 ? 0 : 2;
265  if (slice_y > y)
266  sp += (slice_y - y) * src->linesize[0];
267  for (i = 0; i < height; i++) {
268  uint8_t *d = dp, *s = sp;
269  for (j = 0; j < width; j++) {
270  d[r] = (d[r] * (0xff - s[3]) + s[0] * s[3] + 128) >> 8;
271  d[1] = (d[1] * (0xff - s[3]) + s[1] * s[3] + 128) >> 8;
272  d[b] = (d[b] * (0xff - s[3]) + s[2] * s[3] + 128) >> 8;
273  d += 3;
274  s += 4;
275  }
276  dp += dst->linesize[0];
277  sp += src->linesize[0];
278  }
279  } else {
280  for (i = 0; i < 3; i++) {
281  int hsub = i ? over->hsub : 0;
282  int vsub = i ? over->vsub : 0;
283  uint8_t *dp = dst->data[i] + (x >> hsub) +
284  (start_y >> vsub) * dst->linesize[i];
285  uint8_t *sp = src->data[i];
286  uint8_t *ap = src->data[3];
287  int wp = FFALIGN(width, 1<<hsub) >> hsub;
288  int hp = FFALIGN(height, 1<<vsub) >> vsub;
289  if (slice_y > y) {
290  sp += ((slice_y - y) >> vsub) * src->linesize[i];
291  ap += (slice_y - y) * src->linesize[3];
292  }
293  for (j = 0; j < hp; j++) {
294  uint8_t *d = dp, *s = sp, *a = ap;
295  for (k = 0; k < wp; k++) {
296  // average alpha for color components, improve quality
297  int alpha_v, alpha_h, alpha;
298  if (hsub && vsub && j+1 < hp && k+1 < wp) {
299  alpha = (a[0] + a[src->linesize[3]] +
300  a[1] + a[src->linesize[3]+1]) >> 2;
301  } else if (hsub || vsub) {
302  alpha_h = hsub && k+1 < wp ?
303  (a[0] + a[1]) >> 1 : a[0];
304  alpha_v = vsub && j+1 < hp ?
305  (a[0] + a[src->linesize[3]]) >> 1 : a[0];
306  alpha = (alpha_v + alpha_h) >> 1;
307  } else
308  alpha = a[0];
309  *d = (*d * (0xff - alpha) + *s++ * alpha + 128) >> 8;
310  d++;
311  a += 1 << hsub;
312  }
313  dp += dst->linesize[i];
314  sp += src->linesize[i];
315  ap += (1 << vsub) * src->linesize[3];
316  }
317  }
318  }
319 }
320 
321 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
322 {
323  AVFilterContext *ctx = inlink->dst;
324  AVFilterLink *outlink = ctx->outputs[0];
325  AVFilterBufferRef *outpicref = outlink->out_buf;
326  OverlayContext *over = ctx->priv;
327 
328  if (over->overpicref &&
329  !(over->x >= outpicref->video->w || over->y >= outpicref->video->h ||
330  y+h < over->y || y >= over->y + over->overpicref->video->h)) {
331  blend_slice(ctx, outpicref, over->overpicref, over->x, over->y,
332  over->overpicref->video->w, over->overpicref->video->h,
333  y, outpicref->video->w, h);
334  }
335  avfilter_draw_slice(outlink, y, h, slice_dir);
336 }
337 
338 static void end_frame(AVFilterLink *inlink)
339 {
340  avfilter_end_frame(inlink->dst->outputs[0]);
342 }
343 
344 static void null_draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { }
345 
346 static void null_end_frame(AVFilterLink *inlink) { }
347 
349  .name = "overlay",
350  .description = NULL_IF_CONFIG_SMALL("Overlay a video source on top of the input."),
351 
352  .init = init,
353  .uninit = uninit,
354 
355  .priv_size = sizeof(OverlayContext),
356 
358 
359  .inputs = (AVFilterPad[]) {{ .name = "main",
360  .type = AVMEDIA_TYPE_VIDEO,
361  .start_frame = start_frame,
362  .get_video_buffer= get_video_buffer,
363  .config_props = config_input_main,
364  .draw_slice = draw_slice,
365  .end_frame = end_frame,
366  .min_perms = AV_PERM_READ,
367  .rej_perms = AV_PERM_REUSE2|AV_PERM_PRESERVE, },
368  { .name = "overlay",
369  .type = AVMEDIA_TYPE_VIDEO,
370  .start_frame = start_frame_overlay,
371  .config_props = config_input_overlay,
372  .draw_slice = null_draw_slice,
373  .end_frame = null_end_frame,
374  .min_perms = AV_PERM_READ,
375  .rej_perms = AV_PERM_REUSE2, },
376  { .name = NULL}},
377  .outputs = (AVFilterPad[]) {{ .name = "default",
378  .type = AVMEDIA_TYPE_VIDEO,
379  .config_props = config_output, },
380  { .name = NULL}},
381 };