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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 #include "libavformat/internal.h"
41 #include "libavutil/log.h"
42 #include "libavutil/opt.h"
43 #include "libavutil/parseutils.h"
44 #include "libavutil/time.h"
45 #include <time.h>
46 #include <X11/cursorfont.h>
47 #include <X11/X.h>
48 #include <X11/Xlib.h>
49 #include <X11/Xlibint.h>
50 #include <X11/Xproto.h>
51 #include <X11/Xutil.h>
52 #include <sys/shm.h>
53 #include <X11/extensions/shape.h>
54 #include <X11/extensions/XShm.h>
55 #include <X11/extensions/Xfixes.h>
56 #include "avdevice.h"
57 
58 /**
59  * X11 Device Demuxer context
60  */
61 struct x11grab {
62  const AVClass *class; /**< Class for private options. */
63  int frame_size; /**< Size in bytes of a grabbed frame */
64  AVRational time_base; /**< Time base */
65  int64_t time_frame; /**< Current time */
66 
67  int width; /**< Width of the grab frame */
68  int height; /**< Height of the grab frame */
69  int x_off; /**< Horizontal top-left corner coordinate */
70  int y_off; /**< Vertical top-left corner coordinate */
71 
72  Display *dpy; /**< X11 display from which x11grab grabs frames */
73  XImage *image; /**< X11 image holding the grab */
74  int use_shm; /**< !0 when using XShm extension */
75  XShmSegmentInfo shminfo; /**< When using XShm, keeps track of XShm infos */
76  int draw_mouse; /**< Set by a private option. */
77  int follow_mouse; /**< Set by a private option. */
78  int show_region; /**< set by a private option. */
79  AVRational framerate; /**< Set by a private option. */
81  uint32_t palette[256];
82 
83  Cursor c;
84  Window region_win; /**< This is used by show_region option. */
85 };
86 
87 #define REGION_WIN_BORDER 3
88 /**
89  * Draw grabbing region window
90  *
91  * @param s x11grab context
92  */
93 static void
95 {
96  Display *dpy = s->dpy;
97  int screen;
98  Window win = s->region_win;
99  GC gc;
100 
101  screen = DefaultScreen(dpy);
102  gc = XCreateGC(dpy, win, 0, 0);
103  XSetForeground(dpy, gc, WhitePixel(dpy, screen));
104  XSetBackground(dpy, gc, BlackPixel(dpy, screen));
105  XSetLineAttributes(dpy, gc, REGION_WIN_BORDER, LineDoubleDash, 0, 0);
106  XDrawRectangle(dpy, win, gc,
107  1, 1,
108  (s->width + REGION_WIN_BORDER * 2) - 1 * 2 - 1,
109  (s->height + REGION_WIN_BORDER * 2) - 1 * 2 - 1);
110  XFreeGC(dpy, gc);
111 }
112 
113 /**
114  * Initialize grabbing region window
115  *
116  * @param s x11grab context
117  */
118 static void
120 {
121  Display *dpy = s->dpy;
122  int screen;
123  XSetWindowAttributes attribs;
124  XRectangle rect;
125 
126  screen = DefaultScreen(dpy);
127  attribs.override_redirect = True;
128  s->region_win = XCreateWindow(dpy, RootWindow(dpy, screen),
131  s->width + REGION_WIN_BORDER * 2,
132  s->height + REGION_WIN_BORDER * 2,
133  0, CopyFromParent,
134  InputOutput, CopyFromParent,
135  CWOverrideRedirect, &attribs);
136  rect.x = 0;
137  rect.y = 0;
138  rect.width = s->width;
139  rect.height = s->height;
140  XShapeCombineRectangles(dpy, s->region_win,
141  ShapeBounding, REGION_WIN_BORDER, REGION_WIN_BORDER,
142  &rect, 1, ShapeSubtract, 0);
143  XMapWindow(dpy, s->region_win);
144  XSelectInput(dpy, s->region_win, ExposureMask | StructureNotifyMask);
146 }
147 
148 /**
149  * Initialize the x11 grab device demuxer (public device demuxer API).
150  *
151  * @param s1 Context from avformat core
152  * @return <ul>
153  * <li>AVERROR(ENOMEM) no memory left</li>
154  * <li>AVERROR(EIO) other failure case</li>
155  * <li>0 success</li>
156  * </ul>
157  */
158 static int
160 {
161  struct x11grab *x11grab = s1->priv_data;
162  Display *dpy;
163  AVStream *st = NULL;
164  enum AVPixelFormat input_pixfmt;
165  XImage *image;
166  int x_off = 0;
167  int y_off = 0;
168  int screen;
169  int use_shm = 0;
170  char *dpyname, *offset;
171  int ret = 0;
172  Colormap color_map;
173  XColor color[256];
174  int i;
175 
176  dpyname = av_strdup(s1->filename);
177  if (!dpyname)
178  goto out;
179 
180  offset = strchr(dpyname, '+');
181  if (offset) {
182  sscanf(offset, "%d,%d", &x_off, &y_off);
183  if (strstr(offset, "nomouse")) {
185  "'nomouse' specification in argument is deprecated: "
186  "use 'draw_mouse' option with value 0 instead\n");
187  x11grab->draw_mouse = 0;
188  }
189  *offset= 0;
190  }
191 
192  av_log(s1, AV_LOG_INFO, "device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
193  s1->filename, dpyname, x_off, y_off, x11grab->width, x11grab->height);
194 
195  dpy = XOpenDisplay(dpyname);
196  av_freep(&dpyname);
197  if(!dpy) {
198  av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
199  ret = AVERROR(EIO);
200  goto out;
201  }
202 
203  st = avformat_new_stream(s1, NULL);
204  if (!st) {
205  ret = AVERROR(ENOMEM);
206  goto out;
207  }
208  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
209 
210  screen = DefaultScreen(dpy);
211 
212  if (x11grab->follow_mouse) {
213  int screen_w, screen_h;
214  Window w;
215 
216  screen_w = DisplayWidth(dpy, screen);
217  screen_h = DisplayHeight(dpy, screen);
218  XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off, &ret, &ret, &ret);
219  x_off -= x11grab->width / 2;
220  y_off -= x11grab->height / 2;
221  x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
222  y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
223  av_log(s1, AV_LOG_INFO, "followmouse is enabled, resetting grabbing region to x: %d y: %d\n", x_off, y_off);
224  }
225 
226  if (x11grab->use_shm) {
227  use_shm = XShmQueryExtension(dpy);
228  av_log(s1, AV_LOG_INFO, "shared memory extension%s found\n", use_shm ? "" : " not");
229  }
230 
231  if(use_shm) {
232  int scr = XDefaultScreen(dpy);
233  image = XShmCreateImage(dpy,
234  DefaultVisual(dpy, scr),
235  DefaultDepth(dpy, scr),
236  ZPixmap,
237  NULL,
238  &x11grab->shminfo,
239  x11grab->width, x11grab->height);
240  x11grab->shminfo.shmid = shmget(IPC_PRIVATE,
241  image->bytes_per_line * image->height,
242  IPC_CREAT|0777);
243  if (x11grab->shminfo.shmid == -1) {
244  av_log(s1, AV_LOG_ERROR, "Fatal: Can't get shared memory!\n");
245  ret = AVERROR(ENOMEM);
246  goto out;
247  }
248  x11grab->shminfo.shmaddr = image->data = shmat(x11grab->shminfo.shmid, 0, 0);
249  x11grab->shminfo.readOnly = False;
250 
251  if (!XShmAttach(dpy, &x11grab->shminfo)) {
252  av_log(s1, AV_LOG_ERROR, "Fatal: Failed to attach shared memory!\n");
253  /* needs some better error subroutine :) */
254  ret = AVERROR(EIO);
255  goto out;
256  }
257  } else {
258  image = XGetImage(dpy, RootWindow(dpy, screen),
259  x_off,y_off,
260  x11grab->width, x11grab->height,
261  AllPlanes, ZPixmap);
262  }
263 
264  switch (image->bits_per_pixel) {
265  case 8:
266  av_log (s1, AV_LOG_DEBUG, "8 bit palette\n");
267  input_pixfmt = AV_PIX_FMT_PAL8;
268  color_map = DefaultColormap(dpy, screen);
269  for (i = 0; i < 256; ++i)
270  color[i].pixel = i;
271  XQueryColors(dpy, color_map, color, 256);
272  for (i = 0; i < 256; ++i)
273  x11grab->palette[i] = (color[i].red & 0xFF00) << 8 |
274  (color[i].green & 0xFF00) |
275  (color[i].blue & 0xFF00) >> 8;
276  x11grab->palette_changed = 1;
277  break;
278  case 16:
279  if ( image->red_mask == 0xf800 &&
280  image->green_mask == 0x07e0 &&
281  image->blue_mask == 0x001f ) {
282  av_log (s1, AV_LOG_DEBUG, "16 bit RGB565\n");
283  input_pixfmt = AV_PIX_FMT_RGB565;
284  } else if (image->red_mask == 0x7c00 &&
285  image->green_mask == 0x03e0 &&
286  image->blue_mask == 0x001f ) {
287  av_log(s1, AV_LOG_DEBUG, "16 bit RGB555\n");
288  input_pixfmt = AV_PIX_FMT_RGB555;
289  } else {
290  av_log(s1, AV_LOG_ERROR, "RGB ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
291  av_log(s1, AV_LOG_ERROR, "color masks: r 0x%.6lx g 0x%.6lx b 0x%.6lx\n", image->red_mask, image->green_mask, image->blue_mask);
292  ret = AVERROR_PATCHWELCOME;
293  goto out;
294  }
295  break;
296  case 24:
297  if ( image->red_mask == 0xff0000 &&
298  image->green_mask == 0x00ff00 &&
299  image->blue_mask == 0x0000ff ) {
300  input_pixfmt = AV_PIX_FMT_BGR24;
301  } else if ( image->red_mask == 0x0000ff &&
302  image->green_mask == 0x00ff00 &&
303  image->blue_mask == 0xff0000 ) {
304  input_pixfmt = AV_PIX_FMT_RGB24;
305  } else {
306  av_log(s1, AV_LOG_ERROR,"rgb ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
307  av_log(s1, AV_LOG_ERROR, "color masks: r 0x%.6lx g 0x%.6lx b 0x%.6lx\n", image->red_mask, image->green_mask, image->blue_mask);
308  ret = AVERROR_PATCHWELCOME;
309  goto out;
310  }
311  break;
312  case 32:
313  if ( image->red_mask == 0xff0000 &&
314  image->green_mask == 0x00ff00 &&
315  image->blue_mask == 0x0000ff ) {
316  input_pixfmt = AV_PIX_FMT_0RGB32;
317  } else {
318  av_log(s1, AV_LOG_ERROR,"rgb ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
319  av_log(s1, AV_LOG_ERROR, "color masks: r 0x%.6lx g 0x%.6lx b 0x%.6lx\n", image->red_mask, image->green_mask, image->blue_mask);
320  ret = AVERROR_PATCHWELCOME;
321  goto out;
322  }
323  break;
324  default:
325  av_log(s1, AV_LOG_ERROR, "image depth %i not supported ... aborting\n", image->bits_per_pixel);
326  ret = AVERROR_PATCHWELCOME;
327  goto out;
328  }
329 
330  x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel/8;
331  x11grab->dpy = dpy;
332  x11grab->time_base = av_inv_q(x11grab->framerate);
333  x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
334  x11grab->x_off = x_off;
335  x11grab->y_off = y_off;
336  x11grab->image = image;
337  x11grab->use_shm = use_shm;
338 
341  st->codec->width = x11grab->width;
342  st->codec->height = x11grab->height;
343  st->codec->pix_fmt = input_pixfmt;
344  st->codec->time_base = x11grab->time_base;
345  st->codec->bit_rate = x11grab->frame_size * 1/av_q2d(x11grab->time_base) * 8;
346 
347 out:
348  av_free(dpyname);
349  return ret;
350 }
351 
352 /**
353  * Paint a mouse pointer in an X11 image.
354  *
355  * @param image image to paint the mouse pointer to
356  * @param s context used to retrieve original grabbing rectangle
357  * coordinates
358  */
359 static void
361 {
362  struct x11grab *s = s1->priv_data;
363  int x_off = s->x_off;
364  int y_off = s->y_off;
365  int width = s->width;
366  int height = s->height;
367  Display *dpy = s->dpy;
368  XFixesCursorImage *xcim;
369  int x, y;
370  int line, column;
371  int to_line, to_column;
372  int pixstride = image->bits_per_pixel >> 3;
373  /* Warning: in its insanity, xlib provides unsigned image data through a
374  * char* pointer, so we have to make it uint8_t to make things not break.
375  * Anyone who performs further investigation of the xlib API likely risks
376  * permanent brain damage. */
377  uint8_t *pix = image->data;
378  Window w;
379  XSetWindowAttributes attr;
380 
381  /* Code doesn't currently support 16-bit or PAL8 */
382  if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
383  return;
384 
385  if(!s->c)
386  s->c = XCreateFontCursor(dpy, XC_left_ptr);
387  w = DefaultRootWindow(dpy);
388  attr.cursor = s->c;
389  XChangeWindowAttributes(dpy, w, CWCursor, &attr);
390 
391  xcim = XFixesGetCursorImage(dpy);
392  if (!xcim) {
394  "XFixes extension not available, impossible to draw cursor\n");
395  s->draw_mouse = 0;
396  return;
397  }
398 
399  x = xcim->x - xcim->xhot;
400  y = xcim->y - xcim->yhot;
401 
402  to_line = FFMIN((y + xcim->height), (height + y_off));
403  to_column = FFMIN((x + xcim->width), (width + x_off));
404 
405  for (line = FFMAX(y, y_off); line < to_line; line++) {
406  for (column = FFMAX(x, x_off); column < to_column; column++) {
407  int xcim_addr = (line - y) * xcim->width + column - x;
408  int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
409  int r = (uint8_t)(xcim->pixels[xcim_addr] >> 0);
410  int g = (uint8_t)(xcim->pixels[xcim_addr] >> 8);
411  int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
412  int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);
413 
414  if (a == 255) {
415  pix[image_addr+0] = r;
416  pix[image_addr+1] = g;
417  pix[image_addr+2] = b;
418  } else if (a) {
419  /* pixel values from XFixesGetCursorImage come premultiplied by alpha */
420  pix[image_addr+0] = r + (pix[image_addr+0]*(255-a) + 255/2) / 255;
421  pix[image_addr+1] = g + (pix[image_addr+1]*(255-a) + 255/2) / 255;
422  pix[image_addr+2] = b + (pix[image_addr+2]*(255-a) + 255/2) / 255;
423  }
424  }
425  }
426 
427  XFree(xcim);
428  xcim = NULL;
429 }
430 
431 
432 /**
433  * Read new data in the image structure.
434  *
435  * @param dpy X11 display to grab from
436  * @param d
437  * @param image Image where the grab will be put
438  * @param x Top-Left grabbing rectangle horizontal coordinate
439  * @param y Top-Left grabbing rectangle vertical coordinate
440  * @return 0 if error, !0 if successful
441  */
442 static int
443 xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
444 {
445  xGetImageReply rep;
446  xGetImageReq *req;
447  long nbytes;
448 
449  if (!image) {
450  return 0;
451  }
452 
453  LockDisplay(dpy);
454  GetReq(GetImage, req);
455 
456  /* First set up the standard stuff in the request */
457  req->drawable = d;
458  req->x = x;
459  req->y = y;
460  req->width = image->width;
461  req->height = image->height;
462  req->planeMask = (unsigned int)AllPlanes;
463  req->format = ZPixmap;
464 
465  if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
466  UnlockDisplay(dpy);
467  SyncHandle();
468  return 0;
469  }
470 
471  nbytes = (long)rep.length << 2;
472  _XReadPad(dpy, image->data, nbytes);
473 
474  UnlockDisplay(dpy);
475  SyncHandle();
476  return 1;
477 }
478 
479 /**
480  * Grab a frame from x11 (public device demuxer API).
481  *
482  * @param s1 Context from avformat core
483  * @param pkt Packet holding the brabbed frame
484  * @return frame size in bytes
485  */
486 static int
488 {
489  struct x11grab *s = s1->priv_data;
490  Display *dpy = s->dpy;
491  XImage *image = s->image;
492  int x_off = s->x_off;
493  int y_off = s->y_off;
494 
495  int screen;
496  Window root;
497  int follow_mouse = s->follow_mouse;
498 
499  int64_t curtime, delay;
500  struct timespec ts;
501 
502  /* Calculate the time of the next frame */
503  s->time_frame += INT64_C(1000000);
504 
505  /* wait based on the frame rate */
506  for(;;) {
507  curtime = av_gettime();
508  delay = s->time_frame * av_q2d(s->time_base) - curtime;
509  if (delay <= 0) {
510  if (delay < INT64_C(-1000000) * av_q2d(s->time_base)) {
511  s->time_frame += INT64_C(1000000);
512  }
513  break;
514  }
515  ts.tv_sec = delay / 1000000;
516  ts.tv_nsec = (delay % 1000000) * 1000;
517  nanosleep(&ts, NULL);
518  }
519 
520  av_init_packet(pkt);
521  pkt->data = image->data;
522  pkt->size = s->frame_size;
523  pkt->pts = curtime;
524  if (s->palette_changed) {
527  if (!pal) {
528  av_log(s, AV_LOG_ERROR, "Cannot append palette to packet\n");
529  } else {
530  memcpy(pal, s->palette, AVPALETTE_SIZE);
531  s->palette_changed = 0;
532  }
533  }
534 
535  screen = DefaultScreen(dpy);
536  root = RootWindow(dpy, screen);
537  if (follow_mouse) {
538  int screen_w, screen_h;
539  int pointer_x, pointer_y, _;
540  Window w;
541 
542  screen_w = DisplayWidth(dpy, screen);
543  screen_h = DisplayHeight(dpy, screen);
544  XQueryPointer(dpy, root, &w, &w, &pointer_x, &pointer_y, &_, &_, &_);
545  if (follow_mouse == -1) {
546  // follow the mouse, put it at center of grabbing region
547  x_off += pointer_x - s->width / 2 - x_off;
548  y_off += pointer_y - s->height / 2 - y_off;
549  } else {
550  // follow the mouse, but only move the grabbing region when mouse
551  // reaches within certain pixels to the edge.
552  if (pointer_x > x_off + s->width - follow_mouse) {
553  x_off += pointer_x - (x_off + s->width - follow_mouse);
554  } else if (pointer_x < x_off + follow_mouse)
555  x_off -= (x_off + follow_mouse) - pointer_x;
556  if (pointer_y > y_off + s->height - follow_mouse) {
557  y_off += pointer_y - (y_off + s->height - follow_mouse);
558  } else if (pointer_y < y_off + follow_mouse)
559  y_off -= (y_off + follow_mouse) - pointer_y;
560  }
561  // adjust grabbing region position if it goes out of screen.
562  s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
563  s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);
564 
565  if (s->show_region && s->region_win)
566  XMoveWindow(dpy, s->region_win,
568  s->y_off - REGION_WIN_BORDER);
569  }
570 
571  if (s->show_region) {
572  if (s->region_win) {
573  XEvent evt;
574  // clean up the events, and do the initinal draw or redraw.
575  for (evt.type = NoEventMask; XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask, &evt); );
576  if (evt.type)
578  } else {
580  }
581  }
582 
583  if(s->use_shm) {
584  if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes)) {
585  av_log (s1, AV_LOG_INFO, "XShmGetImage() failed\n");
586  }
587  } else {
588  if (!xget_zpixmap(dpy, root, image, x_off, y_off)) {
589  av_log (s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
590  }
591  }
592 
593  if (s->draw_mouse) {
594  paint_mouse_pointer(image, s1);
595  }
596 
597  return s->frame_size;
598 }
599 
600 /**
601  * Close x11 frame grabber (public device demuxer API).
602  *
603  * @param s1 Context from avformat core
604  * @return 0 success, !0 failure
605  */
606 static int
608 {
609  struct x11grab *x11grab = s1->priv_data;
610 
611  /* Detach cleanly from shared mem */
612  if (x11grab->use_shm) {
613  XShmDetach(x11grab->dpy, &x11grab->shminfo);
614  shmdt(x11grab->shminfo.shmaddr);
615  shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
616  }
617 
618  /* Destroy X11 image */
619  if (x11grab->image) {
620  XDestroyImage(x11grab->image);
621  x11grab->image = NULL;
622  }
623 
624  if (x11grab->region_win) {
625  XDestroyWindow(x11grab->dpy, x11grab->region_win);
626  }
627 
628  /* Free X11 display */
629  XCloseDisplay(x11grab->dpy);
630  return 0;
631 }
632 
633 #define OFFSET(x) offsetof(struct x11grab, x)
634 #define DEC AV_OPT_FLAG_DECODING_PARAM
635 static const AVOption options[] = {
636  { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
637 
638  { "follow_mouse", "move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region",
639  OFFSET(follow_mouse), AV_OPT_TYPE_INT, {.i64 = 0}, -1, INT_MAX, DEC, "follow_mouse" },
640  { "centered", "keep the mouse pointer at the center of grabbing region when following",
641  0, AV_OPT_TYPE_CONST, {.i64 = -1}, INT_MIN, INT_MAX, DEC, "follow_mouse" },
642 
643  { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, 0, DEC },
644  { "show_region", "show the grabbing region", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
645  { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = "vga"}, 0, 0, DEC },
646  { "use_shm", "use MIT-SHM extension", OFFSET(use_shm), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
647  { NULL },
648 };
649 
650 static const AVClass x11_class = {
651  .class_name = "X11grab indev",
652  .item_name = av_default_item_name,
653  .option = options,
654  .version = LIBAVUTIL_VERSION_INT,
656 };
657 
658 /** x11 grabber device demuxer declaration */
660  .name = "x11grab",
661  .long_name = NULL_IF_CONFIG_SMALL("X11grab"),
662  .priv_data_size = sizeof(struct x11grab),
663  .read_header = x11grab_read_header,
664  .read_packet = x11grab_read_packet,
665  .read_close = x11grab_read_close,
666  .flags = AVFMT_NOFILE,
667  .priv_class = &x11_class,
668 };