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x11grab.c
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1 /*
2  * X11 video grab interface
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg integration:
7  * Copyright (C) 2006 Clemens Fruhwirth <clemens@endorphin.org>
8  * Edouard Gomez <ed.gomez@free.fr>
9  *
10  * This file contains code from grab.c:
11  * Copyright (c) 2000-2001 Fabrice Bellard
12  *
13  * This file contains code from the xvidcap project:
14  * Copyright (C) 1997-1998 Rasca, Berlin
15  * 2003-2004 Karl H. Beckers, Frankfurt
16  *
17  * FFmpeg is free software; you can redistribute it and/or modify
18  * it under the terms of the GNU General Public License as published by
19  * the Free Software Foundation; either version 2 of the License, or
20  * (at your option) any later version.
21  *
22  * FFmpeg is distributed in the hope that it will be useful,
23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25  * GNU General Public License for more details.
26  *
27  * You should have received a copy of the GNU General Public License
28  * along with FFmpeg; if not, write to the Free Software
29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30  */
31 
32 /**
33  * @file
34  * X11 frame device demuxer
35  * @author Clemens Fruhwirth <clemens@endorphin.org>
36  * @author Edouard Gomez <ed.gomez@free.fr>
37  */
38 
39 #include "config.h"
40 
41 #include <time.h>
42 #include <sys/shm.h>
43 
44 #include <X11/cursorfont.h>
45 #include <X11/X.h>
46 #include <X11/Xlib.h>
47 #include <X11/Xlibint.h>
48 #include <X11/Xproto.h>
49 #include <X11/Xutil.h>
50 
51 #include <X11/extensions/shape.h>
52 #include <X11/extensions/Xfixes.h>
53 #include <X11/extensions/XShm.h>
54 
55 #include "libavutil/internal.h"
56 #include "libavutil/log.h"
57 #include "libavutil/opt.h"
58 #include "libavutil/parseutils.h"
59 #include "libavutil/time.h"
60 
61 #include "libavformat/internal.h"
62 
63 #include "avdevice.h"
64 
65 /** X11 device demuxer context */
66 typedef struct X11GrabContext {
67  const AVClass *class; /**< Class for private options. */
68  int frame_size; /**< Size in bytes of a grabbed frame */
69  AVRational time_base; /**< Time base */
70  int64_t time_frame; /**< Current time */
71 
72  int width; /**< Width of the grab frame */
73  int height; /**< Height of the grab frame */
74  int x_off; /**< Horizontal top-left corner coordinate */
75  int y_off; /**< Vertical top-left corner coordinate */
76 
77  Display *dpy; /**< X11 display from which x11grab grabs frames */
78  XImage *image; /**< X11 image holding the grab */
79  int use_shm; /**< !0 when using XShm extension */
80  XShmSegmentInfo shminfo; /**< When using XShm, keeps track of XShm infos */
81  int draw_mouse; /**< Set by a private option. */
82  int follow_mouse; /**< Set by a private option. */
83  int show_region; /**< set by a private option. */
84  AVRational framerate; /**< Set by a private option. */
86  uint32_t palette[256];
87 
88  Cursor c;
89  Window region_win; /**< This is used by show_region option. */
91 
92 #define REGION_WIN_BORDER 3
93 
94 /**
95  * Draw grabbing region window
96  *
97  * @param s x11grab context
98  */
100 {
101  Display *dpy = s->dpy;
102  Window win = s->region_win;
103  int screen = DefaultScreen(dpy);
104  GC gc = XCreateGC(dpy, win, 0, 0);
105 
106  XSetForeground(dpy, gc, WhitePixel(dpy, screen));
107  XSetBackground(dpy, gc, BlackPixel(dpy, screen));
108  XSetLineAttributes(dpy, gc, REGION_WIN_BORDER, LineDoubleDash, 0, 0);
109  XDrawRectangle(dpy, win, gc, 1, 1,
110  (s->width + REGION_WIN_BORDER * 2) - 1 * 2 - 1,
111  (s->height + REGION_WIN_BORDER * 2) - 1 * 2 - 1);
112  XFreeGC(dpy, gc);
113 }
114 
115 /**
116  * Initialize grabbing region window
117  *
118  * @param s x11grab context
119  */
121 {
122  Display *dpy = s->dpy;
123  XRectangle rect;
124  XSetWindowAttributes attribs = { .override_redirect = True };
125  int screen = DefaultScreen(dpy);
126 
127  s->region_win = XCreateWindow(dpy, RootWindow(dpy, screen),
130  s->width + REGION_WIN_BORDER * 2,
131  s->height + REGION_WIN_BORDER * 2,
132  0, CopyFromParent,
133  InputOutput, CopyFromParent,
134  CWOverrideRedirect, &attribs);
135  rect.x = 0;
136  rect.y = 0;
137  rect.width = s->width;
138  rect.height = s->height;
139  XShapeCombineRectangles(dpy, s->region_win,
140  ShapeBounding, REGION_WIN_BORDER, REGION_WIN_BORDER,
141  &rect, 1, ShapeSubtract, 0);
142  XMapWindow(dpy, s->region_win);
143  XSelectInput(dpy, s->region_win, ExposureMask | StructureNotifyMask);
145 }
146 
147 static int setup_shm(AVFormatContext *s, Display *dpy, XImage **image)
148 {
149  X11GrabContext *g = s->priv_data;
150  int scr = XDefaultScreen(dpy);
151  XImage *img = XShmCreateImage(dpy, DefaultVisual(dpy, scr),
152  DefaultDepth(dpy, scr), ZPixmap, NULL,
153  &g->shminfo, g->width, g->height);
154 
155  g->shminfo.shmid = shmget(IPC_PRIVATE, img->bytes_per_line * img->height,
156  IPC_CREAT | 0777);
157 
158  if (g->shminfo.shmid == -1) {
159  av_log(s, AV_LOG_ERROR, "Cannot get shared memory!\n");
160  return AVERROR(ENOMEM);
161  }
162 
163  g->shminfo.shmaddr = img->data = shmat(g->shminfo.shmid, 0, 0);
164  g->shminfo.readOnly = False;
165 
166  if (!XShmAttach(dpy, &g->shminfo)) {
167  av_log(s, AV_LOG_ERROR, "Failed to attach shared memory!\n");
168  /* needs some better error subroutine :) */
169  return AVERROR(EIO);
170  }
171 
172  *image = img;
173  return 0;
174 }
175 
176 static int setup_mouse(Display *dpy, int screen)
177 {
178  int ev_ret, ev_err;
179 
180  if (XFixesQueryExtension(dpy, &ev_ret, &ev_err)) {
181  Window root = RootWindow(dpy, screen);
182  XFixesSelectCursorInput(dpy, root, XFixesDisplayCursorNotifyMask);
183  return 0;
184  }
185 
186  return AVERROR(ENOSYS);
187 }
188 
189 static int pixfmt_from_image(AVFormatContext *s, XImage *image, int *pix_fmt)
190 {
191  av_log(s, AV_LOG_DEBUG,
192  "Image r 0x%.6lx g 0x%.6lx b 0x%.6lx and depth %i\n",
193  image->red_mask,
194  image->green_mask,
195  image->blue_mask,
196  image->bits_per_pixel);
197 
198  *pix_fmt = AV_PIX_FMT_NONE;
199 
200  switch (image->bits_per_pixel) {
201  case 8:
202  *pix_fmt = AV_PIX_FMT_PAL8;
203  break;
204  case 16:
205  if (image->red_mask == 0xf800 &&
206  image->green_mask == 0x07e0 &&
207  image->blue_mask == 0x001f) {
208  *pix_fmt = AV_PIX_FMT_RGB565;
209  } else if (image->red_mask == 0x7c00 &&
210  image->green_mask == 0x03e0 &&
211  image->blue_mask == 0x001f) {
212  *pix_fmt = AV_PIX_FMT_RGB555;
213  }
214  break;
215  case 24:
216  if (image->red_mask == 0xff0000 &&
217  image->green_mask == 0x00ff00 &&
218  image->blue_mask == 0x0000ff) {
219  *pix_fmt = AV_PIX_FMT_BGR24;
220  } else if (image->red_mask == 0x0000ff &&
221  image->green_mask == 0x00ff00 &&
222  image->blue_mask == 0xff0000) {
223  *pix_fmt = AV_PIX_FMT_RGB24;
224  }
225  break;
226  case 32:
227  if (image->red_mask == 0xff0000 &&
228  image->green_mask == 0x00ff00 &&
229  image->blue_mask == 0x0000ff ) {
230  *pix_fmt = AV_PIX_FMT_0RGB32;
231  }
232  break;
233  }
234  if (*pix_fmt == AV_PIX_FMT_NONE) {
235  av_log(s, AV_LOG_ERROR,
236  "XImages with RGB mask 0x%.6lx 0x%.6lx 0x%.6lx and depth %i "
237  "are currently not supported.\n",
238  image->red_mask,
239  image->green_mask,
240  image->blue_mask,
241  image->bits_per_pixel);
242 
243  return AVERROR_PATCHWELCOME;
244  }
245 
246  return 0;
247 }
248 
249 /**
250  * Initialize the x11 grab device demuxer (public device demuxer API).
251  *
252  * @param s1 Context from avformat core
253  * @return <ul>
254  * <li>AVERROR(ENOMEM) no memory left</li>
255  * <li>AVERROR(EIO) other failure case</li>
256  * <li>0 success</li>
257  * </ul>
258  */
260 {
261  X11GrabContext *x11grab = s1->priv_data;
262  Display *dpy;
263  AVStream *st = NULL;
264  XImage *image;
265  int x_off = 0, y_off = 0, ret = 0, screen, use_shm = 0;
266  char *dpyname, *offset;
267  Colormap color_map;
268  XColor color[256];
269  int i;
270 
271  dpyname = av_strdup(s1->filename);
272  if (!dpyname)
273  goto out;
274 
275  offset = strchr(dpyname, '+');
276  if (offset) {
277  sscanf(offset, "%d,%d", &x_off, &y_off);
278  if (strstr(offset, "nomouse")) {
280  "'nomouse' specification in argument is deprecated: "
281  "use 'draw_mouse' option with value 0 instead\n");
282  x11grab->draw_mouse = 0;
283  }
284  *offset = 0;
285  }
286 
287  av_log(s1, AV_LOG_INFO,
288  "device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
289  s1->filename, dpyname, x_off, y_off, x11grab->width, x11grab->height);
290 
291  dpy = XOpenDisplay(dpyname);
292  av_freep(&dpyname);
293  if (!dpy) {
294  av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
295  ret = AVERROR(EIO);
296  goto out;
297  }
298 
299  st = avformat_new_stream(s1, NULL);
300  if (!st) {
301  ret = AVERROR(ENOMEM);
302  goto out;
303  }
304  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
305 
306  screen = DefaultScreen(dpy);
307 
308  if (x11grab->follow_mouse) {
309  int screen_w, screen_h;
310  Window w;
311 
312  screen_w = DisplayWidth(dpy, screen);
313  screen_h = DisplayHeight(dpy, screen);
314  XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off,
315  &ret, &ret, &ret);
316  x_off -= x11grab->width / 2;
317  y_off -= x11grab->height / 2;
318  x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
319  y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
320  av_log(s1, AV_LOG_INFO,
321  "followmouse is enabled, resetting grabbing region to x: %d y: %d\n",
322  x_off, y_off);
323  }
324 
325  if (x11grab->use_shm) {
326  use_shm = XShmQueryExtension(dpy);
327  av_log(s1, AV_LOG_INFO,
328  "shared memory extension %sfound\n", use_shm ? "" : "not ");
329  }
330 
331  if (use_shm && setup_shm(s1, dpy, &image) < 0) {
332  av_log(s1, AV_LOG_WARNING, "Falling back to XGetImage\n");
333  use_shm = 0;
334  }
335 
336  if (!use_shm) {
337  image = XGetImage(dpy, RootWindow(dpy, screen),
338  x_off, y_off,
339  x11grab->width, x11grab->height,
340  AllPlanes, ZPixmap);
341  }
342 
343  if (x11grab->draw_mouse && setup_mouse(dpy, screen) < 0) {
345  "XFixes not available, cannot draw the mouse cursor\n");
346  x11grab->draw_mouse = 0;
347  }
348 
349  x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel / 8;
350  x11grab->dpy = dpy;
351  x11grab->time_base = av_inv_q(x11grab->framerate);
352  x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
353  x11grab->x_off = x_off;
354  x11grab->y_off = y_off;
355  x11grab->image = image;
356  x11grab->use_shm = use_shm;
357 
358  ret = pixfmt_from_image(s1, image, &st->codec->pix_fmt);
359  if (ret < 0)
360  goto out;
361 
362  if (st->codec->pix_fmt == AV_PIX_FMT_PAL8) {
363  color_map = DefaultColormap(dpy, screen);
364  for (i = 0; i < 256; ++i)
365  color[i].pixel = i;
366  XQueryColors(dpy, color_map, color, 256);
367  for (i = 0; i < 256; ++i)
368  x11grab->palette[i] = (color[i].red & 0xFF00) << 8 |
369  (color[i].green & 0xFF00) |
370  (color[i].blue & 0xFF00) >> 8;
371  x11grab->palette_changed = 1;
372  }
373 
374 
377  st->codec->width = x11grab->width;
378  st->codec->height = x11grab->height;
379  st->codec->time_base = x11grab->time_base;
380  st->codec->bit_rate = x11grab->frame_size * 1 / av_q2d(x11grab->time_base) * 8;
381 
382 out:
383  av_free(dpyname);
384  return ret;
385 }
386 
387 /**
388  * Paint a mouse pointer in an X11 image.
389  *
390  * @param image image to paint the mouse pointer to
391  * @param s context used to retrieve original grabbing rectangle
392  * coordinates
393  */
394 static void paint_mouse_pointer(XImage *image, AVFormatContext *s1)
395 {
396  X11GrabContext *s = s1->priv_data;
397  int x_off = s->x_off;
398  int y_off = s->y_off;
399  int width = s->width;
400  int height = s->height;
401  Display *dpy = s->dpy;
402  XFixesCursorImage *xcim;
403  int x, y;
404  int line, column;
405  int to_line, to_column;
406  int pixstride = image->bits_per_pixel >> 3;
407  /* Warning: in its insanity, xlib provides unsigned image data through a
408  * char* pointer, so we have to make it uint8_t to make things not break.
409  * Anyone who performs further investigation of the xlib API likely risks
410  * permanent brain damage. */
411  uint8_t *pix = image->data;
412  Window root;
413  XSetWindowAttributes attr;
414 
415  /* Code doesn't currently support 16-bit or PAL8 */
416  if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
417  return;
418 
419  if (!s->c)
420  s->c = XCreateFontCursor(dpy, XC_left_ptr);
421  root = DefaultRootWindow(dpy);
422  attr.cursor = s->c;
423  XChangeWindowAttributes(dpy, root, CWCursor, &attr);
424 
425  xcim = XFixesGetCursorImage(dpy);
426  if (!xcim) {
428  "XFixesGetCursorImage failed\n");
429  return;
430  }
431 
432  x = xcim->x - xcim->xhot;
433  y = xcim->y - xcim->yhot;
434 
435  to_line = FFMIN((y + xcim->height), (height + y_off));
436  to_column = FFMIN((x + xcim->width), (width + x_off));
437 
438  for (line = FFMAX(y, y_off); line < to_line; line++) {
439  for (column = FFMAX(x, x_off); column < to_column; column++) {
440  int xcim_addr = (line - y) * xcim->width + column - x;
441  int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
442  int r = (uint8_t)(xcim->pixels[xcim_addr] >> 0);
443  int g = (uint8_t)(xcim->pixels[xcim_addr] >> 8);
444  int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
445  int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);
446 
447  if (a == 255) {
448  pix[image_addr + 0] = r;
449  pix[image_addr + 1] = g;
450  pix[image_addr + 2] = b;
451  } else if (a) {
452  /* pixel values from XFixesGetCursorImage come premultiplied by alpha */
453  pix[image_addr + 0] = r + (pix[image_addr + 0] * (255 - a) + 255 / 2) / 255;
454  pix[image_addr + 1] = g + (pix[image_addr + 1] * (255 - a) + 255 / 2) / 255;
455  pix[image_addr + 2] = b + (pix[image_addr + 2] * (255 - a) + 255 / 2) / 255;
456  }
457  }
458  }
459 
460  XFree(xcim);
461  xcim = NULL;
462 }
463 
464 /**
465  * Read new data in the image structure.
466  *
467  * @param dpy X11 display to grab from
468  * @param d
469  * @param image Image where the grab will be put
470  * @param x Top-Left grabbing rectangle horizontal coordinate
471  * @param y Top-Left grabbing rectangle vertical coordinate
472  * @return 0 if error, !0 if successful
473  */
474 static int xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
475 {
476  xGetImageReply rep;
477  xGetImageReq *req;
478  long nbytes;
479 
480  if (!image)
481  return 0;
482 
483  LockDisplay(dpy);
484  GetReq(GetImage, req);
485 
486  /* First set up the standard stuff in the request */
487  req->drawable = d;
488  req->x = x;
489  req->y = y;
490  req->width = image->width;
491  req->height = image->height;
492  req->planeMask = (unsigned int)AllPlanes;
493  req->format = ZPixmap;
494 
495  if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
496  UnlockDisplay(dpy);
497  SyncHandle();
498  return 0;
499  }
500 
501  nbytes = (long)rep.length << 2;
502  _XReadPad(dpy, image->data, nbytes);
503 
504  UnlockDisplay(dpy);
505  SyncHandle();
506  return 1;
507 }
508 
509 /**
510  * Grab a frame from x11 (public device demuxer API).
511  *
512  * @param s1 Context from avformat core
513  * @param pkt Packet holding the brabbed frame
514  * @return frame size in bytes
515  */
517 {
518  X11GrabContext *s = s1->priv_data;
519  Display *dpy = s->dpy;
520  XImage *image = s->image;
521  int x_off = s->x_off;
522  int y_off = s->y_off;
523  int follow_mouse = s->follow_mouse;
524  int screen, pointer_x, pointer_y, _, same_screen = 1;
525  Window w, root;
526  int64_t curtime, delay;
527  struct timespec ts;
528 
529  /* Calculate the time of the next frame */
530  s->time_frame += INT64_C(1000000);
531 
532  /* wait based on the frame rate */
533  for (;;) {
534  curtime = av_gettime();
535  delay = s->time_frame * av_q2d(s->time_base) - curtime;
536  if (delay <= 0) {
537  if (delay < INT64_C(-1000000) * av_q2d(s->time_base))
538  s->time_frame += INT64_C(1000000);
539  break;
540  }
541  ts.tv_sec = delay / 1000000;
542  ts.tv_nsec = (delay % 1000000) * 1000;
543  nanosleep(&ts, NULL);
544  }
545 
546  av_init_packet(pkt);
547  pkt->data = image->data;
548  pkt->size = s->frame_size;
549  pkt->pts = curtime;
550  if (s->palette_changed) {
553  if (!pal) {
554  av_log(s, AV_LOG_ERROR, "Cannot append palette to packet\n");
555  } else {
556  memcpy(pal, s->palette, AVPALETTE_SIZE);
557  s->palette_changed = 0;
558  }
559  }
560 
561  screen = DefaultScreen(dpy);
562  root = RootWindow(dpy, screen);
563 
564  if (follow_mouse || s->draw_mouse)
565  same_screen = XQueryPointer(dpy, root, &w, &w,
566  &pointer_x, &pointer_y, &_, &_, &_);
567 
568  if (follow_mouse && same_screen) {
569  int screen_w, screen_h;
570 
571  screen_w = DisplayWidth(dpy, screen);
572  screen_h = DisplayHeight(dpy, screen);
573  if (follow_mouse == -1) {
574  // follow the mouse, put it at center of grabbing region
575  x_off += pointer_x - s->width / 2 - x_off;
576  y_off += pointer_y - s->height / 2 - y_off;
577  } else {
578  // follow the mouse, but only move the grabbing region when mouse
579  // reaches within certain pixels to the edge.
580  if (pointer_x > x_off + s->width - follow_mouse)
581  x_off += pointer_x - (x_off + s->width - follow_mouse);
582  else if (pointer_x < x_off + follow_mouse)
583  x_off -= (x_off + follow_mouse) - pointer_x;
584  if (pointer_y > y_off + s->height - follow_mouse)
585  y_off += pointer_y - (y_off + s->height - follow_mouse);
586  else if (pointer_y < y_off + follow_mouse)
587  y_off -= (y_off + follow_mouse) - pointer_y;
588  }
589  // adjust grabbing region position if it goes out of screen.
590  s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
591  s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);
592 
593  if (s->show_region && s->region_win)
594  XMoveWindow(dpy, s->region_win,
596  s->y_off - REGION_WIN_BORDER);
597  }
598 
599  if (s->show_region && same_screen) {
600  if (s->region_win) {
601  XEvent evt = { .type = NoEventMask };
602  // Clean up the events, and do the initial draw or redraw.
603  while (XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask,
604  &evt))
605  ;
606  if (evt.type)
608  } else {
610  }
611  }
612 
613  if (s->use_shm) {
614  if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes))
615  av_log(s1, AV_LOG_INFO, "XShmGetImage() failed\n");
616  } else {
617  if (!xget_zpixmap(dpy, root, image, x_off, y_off))
618  av_log(s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
619  }
620 
621  if (s->draw_mouse && same_screen)
622  paint_mouse_pointer(image, s1);
623 
624  return s->frame_size;
625 }
626 
627 /**
628  * Close x11 frame grabber (public device demuxer API).
629  *
630  * @param s1 Context from avformat core
631  * @return 0 success, !0 failure
632  */
634 {
635  X11GrabContext *x11grab = s1->priv_data;
636 
637  /* Detach cleanly from shared mem */
638  if (x11grab->use_shm) {
639  XShmDetach(x11grab->dpy, &x11grab->shminfo);
640  shmdt(x11grab->shminfo.shmaddr);
641  shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
642  }
643 
644  /* Destroy X11 image */
645  if (x11grab->image) {
646  XDestroyImage(x11grab->image);
647  x11grab->image = NULL;
648  }
649 
650  if (x11grab->region_win)
651  XDestroyWindow(x11grab->dpy, x11grab->region_win);
652 
653  /* Free X11 display */
654  XCloseDisplay(x11grab->dpy);
655  return 0;
656 }
657 
658 #define OFFSET(x) offsetof(X11GrabContext, x)
659 #define DEC AV_OPT_FLAG_DECODING_PARAM
660 static const AVOption options[] = {
661  { "grab_x", "Initial x coordinate.", OFFSET(x_off), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
662  { "grab_y", "Initial y coordinate.", OFFSET(y_off), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
663  { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
664 
665  { "follow_mouse", "move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region",
666  OFFSET(follow_mouse), AV_OPT_TYPE_INT, {.i64 = 0}, -1, INT_MAX, DEC, "follow_mouse" },
667  { "centered", "keep the mouse pointer at the center of grabbing region when following",
668  0, AV_OPT_TYPE_CONST, {.i64 = -1}, INT_MIN, INT_MAX, DEC, "follow_mouse" },
669 
670  { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, 0, DEC },
671  { "show_region", "show the grabbing region", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
672  { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = "vga"}, 0, 0, DEC },
673  { "use_shm", "use MIT-SHM extension", OFFSET(use_shm), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
674  { NULL },
675 };
676 
677 static const AVClass x11_class = {
678  .class_name = "X11grab indev",
679  .item_name = av_default_item_name,
680  .option = options,
681  .version = LIBAVUTIL_VERSION_INT,
683 };
684 
685 /** x11 grabber device demuxer declaration */
687  .name = "x11grab",
688  .long_name = NULL_IF_CONFIG_SMALL("X11grab"),
689  .priv_data_size = sizeof(X11GrabContext),
693  .flags = AVFMT_NOFILE,
694  .priv_class = &x11_class,
695 };