x11grab.c
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1 /*
2  * X11 video grab interface
3  *
4  * This file is part of Libav.
5  *
6  * Libav 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  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30  */
31 
39 #include "config.h"
40 #include "libavformat/avformat.h"
41 #include "libavformat/internal.h"
42 #include "libavutil/log.h"
43 #include "libavutil/opt.h"
44 #include "libavutil/parseutils.h"
45 #include <time.h>
46 #include <X11/X.h>
47 #include <X11/Xlib.h>
48 #include <X11/Xlibint.h>
49 #include <X11/Xproto.h>
50 #include <X11/Xutil.h>
51 #include <sys/shm.h>
52 #include <X11/extensions/shape.h>
53 #include <X11/extensions/XShm.h>
54 #include <X11/extensions/Xfixes.h>
55 
59 struct x11_grab
60 {
61  const AVClass *class;
62  int frame_size;
64  int64_t time_frame;
66  char *video_size;
67  int height;
68  int width;
69  int x_off;
70  int y_off;
72  Display *dpy;
73  XImage *image;
74  int use_shm;
75  XShmSegmentInfo shminfo;
76  int draw_mouse;
79  char *framerate;
81  Window region_win;
82 };
83 
84 #define REGION_WIN_BORDER 3
85 
90 static void
92 {
93  Display *dpy = s->dpy;
94  int screen;
95  Window win = s->region_win;
96  GC gc;
97 
98  screen = DefaultScreen(dpy);
99  gc = XCreateGC(dpy, win, 0, 0);
100  XSetForeground(dpy, gc, WhitePixel(dpy, screen));
101  XSetBackground(dpy, gc, BlackPixel(dpy, screen));
102  XSetLineAttributes(dpy, gc, REGION_WIN_BORDER, LineDoubleDash, 0, 0);
103  XDrawRectangle(dpy, win, gc,
104  1, 1,
105  (s->width + REGION_WIN_BORDER * 2) - 1 * 2 - 1,
106  (s->height + REGION_WIN_BORDER * 2) - 1 * 2 - 1);
107  XFreeGC(dpy, gc);
108 }
109 
115 static void
117 {
118  Display *dpy = s->dpy;
119  int screen;
120  XSetWindowAttributes attribs;
121  XRectangle rect;
122 
123  screen = DefaultScreen(dpy);
124  attribs.override_redirect = True;
125  s->region_win = XCreateWindow(dpy, RootWindow(dpy, screen),
128  s->width + REGION_WIN_BORDER * 2,
129  s->height + REGION_WIN_BORDER * 2,
130  0, CopyFromParent,
131  InputOutput, CopyFromParent,
132  CWOverrideRedirect, &attribs);
133  rect.x = 0;
134  rect.y = 0;
135  rect.width = s->width;
136  rect.height = s->height;
137  XShapeCombineRectangles(dpy, s->region_win,
138  ShapeBounding, REGION_WIN_BORDER, REGION_WIN_BORDER,
139  &rect, 1, ShapeSubtract, 0);
140  XMapWindow(dpy, s->region_win);
141  XSelectInput(dpy, s->region_win, ExposureMask | StructureNotifyMask);
143 }
144 
156 static int
158 {
159  struct x11_grab *x11grab = s1->priv_data;
160  Display *dpy;
161  AVStream *st = NULL;
162  enum PixelFormat input_pixfmt;
163  XImage *image;
164  int x_off = 0;
165  int y_off = 0;
166  int screen;
167  int use_shm;
168  char *param, *offset;
169  int ret = 0;
171 
172  param = av_strdup(s1->filename);
173  offset = strchr(param, '+');
174  if (offset) {
175  sscanf(offset, "%d,%d", &x_off, &y_off);
176  x11grab->draw_mouse = !strstr(offset, "nomouse");
177  *offset= 0;
178  }
179 
180  if ((ret = av_parse_video_size(&x11grab->width, &x11grab->height, x11grab->video_size)) < 0) {
181  av_log(s1, AV_LOG_ERROR, "Couldn't parse video size.\n");
182  goto out;
183  }
184  if ((ret = av_parse_video_rate(&framerate, x11grab->framerate)) < 0) {
185  av_log(s1, AV_LOG_ERROR, "Could not parse framerate: %s.\n", x11grab->framerate);
186  goto out;
187  }
188  av_log(s1, AV_LOG_INFO, "device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
189  s1->filename, param, x_off, y_off, x11grab->width, x11grab->height);
190 
191  dpy = XOpenDisplay(param);
192  if(!dpy) {
193  av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
194  ret = AVERROR(EIO);
195  goto out;
196  }
197 
198  st = avformat_new_stream(s1, NULL);
199  if (!st) {
200  ret = AVERROR(ENOMEM);
201  goto out;
202  }
203  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
204 
205  screen = DefaultScreen(dpy);
206 
207  if (x11grab->follow_mouse) {
208  int screen_w, screen_h;
209  Window w;
210 
211  screen_w = DisplayWidth(dpy, screen);
212  screen_h = DisplayHeight(dpy, screen);
213  XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off, &ret, &ret, &ret);
214  x_off -= x11grab->width / 2;
215  y_off -= x11grab->height / 2;
216  x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
217  y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
218  av_log(s1, AV_LOG_INFO, "followmouse is enabled, resetting grabbing region to x: %d y: %d\n", x_off, y_off);
219  }
220 
221  use_shm = XShmQueryExtension(dpy);
222  av_log(s1, AV_LOG_INFO, "shared memory extension %s found\n", use_shm ? "" : "not");
223 
224  if(use_shm) {
225  int scr = XDefaultScreen(dpy);
226  image = XShmCreateImage(dpy,
227  DefaultVisual(dpy, scr),
228  DefaultDepth(dpy, scr),
229  ZPixmap,
230  NULL,
231  &x11grab->shminfo,
232  x11grab->width, x11grab->height);
233  x11grab->shminfo.shmid = shmget(IPC_PRIVATE,
234  image->bytes_per_line * image->height,
235  IPC_CREAT|0777);
236  if (x11grab->shminfo.shmid == -1) {
237  av_log(s1, AV_LOG_ERROR, "Fatal: Can't get shared memory!\n");
238  ret = AVERROR(ENOMEM);
239  goto out;
240  }
241  x11grab->shminfo.shmaddr = image->data = shmat(x11grab->shminfo.shmid, 0, 0);
242  x11grab->shminfo.readOnly = False;
243 
244  if (!XShmAttach(dpy, &x11grab->shminfo)) {
245  av_log(s1, AV_LOG_ERROR, "Fatal: Failed to attach shared memory!\n");
246  /* needs some better error subroutine :) */
247  ret = AVERROR(EIO);
248  goto out;
249  }
250  } else {
251  image = XGetImage(dpy, RootWindow(dpy, screen),
252  x_off,y_off,
253  x11grab->width, x11grab->height,
254  AllPlanes, ZPixmap);
255  }
256 
257  switch (image->bits_per_pixel) {
258  case 8:
259  av_log (s1, AV_LOG_DEBUG, "8 bit palette\n");
260  input_pixfmt = PIX_FMT_PAL8;
261  break;
262  case 16:
263  if ( image->red_mask == 0xf800 &&
264  image->green_mask == 0x07e0 &&
265  image->blue_mask == 0x001f ) {
266  av_log (s1, AV_LOG_DEBUG, "16 bit RGB565\n");
267  input_pixfmt = PIX_FMT_RGB565;
268  } else if (image->red_mask == 0x7c00 &&
269  image->green_mask == 0x03e0 &&
270  image->blue_mask == 0x001f ) {
271  av_log(s1, AV_LOG_DEBUG, "16 bit RGB555\n");
272  input_pixfmt = PIX_FMT_RGB555;
273  } else {
274  av_log(s1, AV_LOG_ERROR, "RGB ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
275  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);
276  ret = AVERROR(EIO);
277  goto out;
278  }
279  break;
280  case 24:
281  if ( image->red_mask == 0xff0000 &&
282  image->green_mask == 0x00ff00 &&
283  image->blue_mask == 0x0000ff ) {
284  input_pixfmt = PIX_FMT_BGR24;
285  } else if ( image->red_mask == 0x0000ff &&
286  image->green_mask == 0x00ff00 &&
287  image->blue_mask == 0xff0000 ) {
288  input_pixfmt = PIX_FMT_RGB24;
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(EIO);
293  goto out;
294  }
295  break;
296  case 32:
297  input_pixfmt = PIX_FMT_RGB32;
298  break;
299  default:
300  av_log(s1, AV_LOG_ERROR, "image depth %i not supported ... aborting\n", image->bits_per_pixel);
301  ret = AVERROR(EINVAL);
302  goto out;
303  }
304 
305  x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel/8;
306  x11grab->dpy = dpy;
307  x11grab->time_base = (AVRational){framerate.den, framerate.num};
308  x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
309  x11grab->x_off = x_off;
310  x11grab->y_off = y_off;
311  x11grab->image = image;
312  x11grab->use_shm = use_shm;
313 
316  st->codec->width = x11grab->width;
317  st->codec->height = x11grab->height;
318  st->codec->pix_fmt = input_pixfmt;
319  st->codec->time_base = x11grab->time_base;
320  st->codec->bit_rate = x11grab->frame_size * 1/av_q2d(x11grab->time_base) * 8;
321 
322 out:
323  return ret;
324 }
325 
333 static void
334 paint_mouse_pointer(XImage *image, struct x11_grab *s)
335 {
336  int x_off = s->x_off;
337  int y_off = s->y_off;
338  int width = s->width;
339  int height = s->height;
340  Display *dpy = s->dpy;
341  XFixesCursorImage *xcim;
342  int x, y;
343  int line, column;
344  int to_line, to_column;
345  int pixstride = image->bits_per_pixel >> 3;
346  /* Warning: in its insanity, xlib provides unsigned image data through a
347  * char* pointer, so we have to make it uint8_t to make things not break.
348  * Anyone who performs further investigation of the xlib API likely risks
349  * permanent brain damage. */
350  uint8_t *pix = image->data;
351 
352  /* Code doesn't currently support 16-bit or PAL8 */
353  if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
354  return;
355 
356  xcim = XFixesGetCursorImage(dpy);
357 
358  x = xcim->x - xcim->xhot;
359  y = xcim->y - xcim->yhot;
360 
361  to_line = FFMIN((y + xcim->height), (height + y_off));
362  to_column = FFMIN((x + xcim->width), (width + x_off));
363 
364  for (line = FFMAX(y, y_off); line < to_line; line++) {
365  for (column = FFMAX(x, x_off); column < to_column; column++) {
366  int xcim_addr = (line - y) * xcim->width + column - x;
367  int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
368  int r = (uint8_t)(xcim->pixels[xcim_addr] >> 0);
369  int g = (uint8_t)(xcim->pixels[xcim_addr] >> 8);
370  int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
371  int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);
372 
373  if (a == 255) {
374  pix[image_addr+0] = r;
375  pix[image_addr+1] = g;
376  pix[image_addr+2] = b;
377  } else if (a) {
378  /* pixel values from XFixesGetCursorImage come premultiplied by alpha */
379  pix[image_addr+0] = r + (pix[image_addr+0]*(255-a) + 255/2) / 255;
380  pix[image_addr+1] = g + (pix[image_addr+1]*(255-a) + 255/2) / 255;
381  pix[image_addr+2] = b + (pix[image_addr+2]*(255-a) + 255/2) / 255;
382  }
383  }
384  }
385 
386  XFree(xcim);
387  xcim = NULL;
388 }
389 
390 
401 static int
402 xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
403 {
404  xGetImageReply rep;
405  xGetImageReq *req;
406  long nbytes;
407 
408  if (!image) {
409  return 0;
410  }
411 
412  LockDisplay(dpy);
413  GetReq(GetImage, req);
414 
415  /* First set up the standard stuff in the request */
416  req->drawable = d;
417  req->x = x;
418  req->y = y;
419  req->width = image->width;
420  req->height = image->height;
421  req->planeMask = (unsigned int)AllPlanes;
422  req->format = ZPixmap;
423 
424  if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
425  UnlockDisplay(dpy);
426  SyncHandle();
427  return 0;
428  }
429 
430  nbytes = (long)rep.length << 2;
431  _XReadPad(dpy, image->data, nbytes);
432 
433  UnlockDisplay(dpy);
434  SyncHandle();
435  return 1;
436 }
437 
445 static int
447 {
448  struct x11_grab *s = s1->priv_data;
449  Display *dpy = s->dpy;
450  XImage *image = s->image;
451  int x_off = s->x_off;
452  int y_off = s->y_off;
453 
454  int screen;
455  Window root;
456  int follow_mouse = s->follow_mouse;
457 
458  int64_t curtime, delay;
459  struct timespec ts;
460 
461  /* Calculate the time of the next frame */
462  s->time_frame += INT64_C(1000000);
463 
464  /* wait based on the frame rate */
465  for(;;) {
466  curtime = av_gettime();
467  delay = s->time_frame * av_q2d(s->time_base) - curtime;
468  if (delay <= 0) {
469  if (delay < INT64_C(-1000000) * av_q2d(s->time_base)) {
470  s->time_frame += INT64_C(1000000);
471  }
472  break;
473  }
474  ts.tv_sec = delay / 1000000;
475  ts.tv_nsec = (delay % 1000000) * 1000;
476  nanosleep(&ts, NULL);
477  }
478 
479  av_init_packet(pkt);
480  pkt->data = image->data;
481  pkt->size = s->frame_size;
482  pkt->pts = curtime;
483 
484  screen = DefaultScreen(dpy);
485  root = RootWindow(dpy, screen);
486  if (follow_mouse) {
487  int screen_w, screen_h;
488  int pointer_x, pointer_y, _;
489  Window w;
490 
491  screen_w = DisplayWidth(dpy, screen);
492  screen_h = DisplayHeight(dpy, screen);
493  XQueryPointer(dpy, root, &w, &w, &pointer_x, &pointer_y, &_, &_, &_);
494  if (follow_mouse == -1) {
495  // follow the mouse, put it at center of grabbing region
496  x_off += pointer_x - s->width / 2 - x_off;
497  y_off += pointer_y - s->height / 2 - y_off;
498  } else {
499  // follow the mouse, but only move the grabbing region when mouse
500  // reaches within certain pixels to the edge.
501  if (pointer_x > x_off + s->width - follow_mouse) {
502  x_off += pointer_x - (x_off + s->width - follow_mouse);
503  } else if (pointer_x < x_off + follow_mouse)
504  x_off -= (x_off + follow_mouse) - pointer_x;
505  if (pointer_y > y_off + s->height - follow_mouse) {
506  y_off += pointer_y - (y_off + s->height - follow_mouse);
507  } else if (pointer_y < y_off + follow_mouse)
508  y_off -= (y_off + follow_mouse) - pointer_y;
509  }
510  // adjust grabbing region position if it goes out of screen.
511  s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
512  s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);
513 
514  if (s->show_region && s->region_win)
515  XMoveWindow(dpy, s->region_win,
517  s->y_off - REGION_WIN_BORDER);
518  }
519 
520  if (s->show_region) {
521  if (s->region_win) {
522  XEvent evt;
523  // clean up the events, and do the initinal draw or redraw.
524  for (evt.type = NoEventMask; XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask, &evt); );
525  if (evt.type)
527  } else {
529  }
530  }
531 
532  if(s->use_shm) {
533  if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes)) {
534  av_log (s1, AV_LOG_INFO, "XShmGetImage() failed\n");
535  }
536  } else {
537  if (!xget_zpixmap(dpy, root, image, x_off, y_off)) {
538  av_log (s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
539  }
540  }
541 
542  if (s->draw_mouse) {
543  paint_mouse_pointer(image, s);
544  }
545 
546  return s->frame_size;
547 }
548 
555 static int
557 {
558  struct x11_grab *x11grab = s1->priv_data;
559 
560  /* Detach cleanly from shared mem */
561  if (x11grab->use_shm) {
562  XShmDetach(x11grab->dpy, &x11grab->shminfo);
563  shmdt(x11grab->shminfo.shmaddr);
564  shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
565  }
566 
567  /* Destroy X11 image */
568  if (x11grab->image) {
569  XDestroyImage(x11grab->image);
570  x11grab->image = NULL;
571  }
572 
573  if (x11grab->region_win) {
574  XDestroyWindow(x11grab->dpy, x11grab->region_win);
575  }
576 
577  /* Free X11 display */
578  XCloseDisplay(x11grab->dpy);
579  return 0;
580 }
581 
582 #define OFFSET(x) offsetof(struct x11_grab, x)
583 #define DEC AV_OPT_FLAG_DECODING_PARAM
584 static const AVOption options[] = {
585  { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), AV_OPT_TYPE_STRING, {.str = "vga"}, 0, 0, DEC },
586  { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc"}, 0, 0, DEC },
587  { "draw_mouse", "Draw the mouse pointer.", OFFSET(draw_mouse), AV_OPT_TYPE_INT, { 1 }, 0, 1, DEC },
588  { "follow_mouse", "Move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region.",
589  OFFSET(follow_mouse), AV_OPT_TYPE_INT, { 0 }, -1, INT_MAX, DEC, "follow_mouse" },
590  { "centered", "Keep the mouse pointer at the center of grabbing region when following.", 0, AV_OPT_TYPE_CONST, { -1 }, INT_MIN, INT_MAX, DEC, "follow_mouse" },
591  { "show_region", "Show the grabbing region.", OFFSET(show_region), AV_OPT_TYPE_INT, { 0 }, 0, 1, DEC },
592  { NULL },
593 };
594 
595 static const AVClass x11_class = {
596  .class_name = "X11grab indev",
597  .item_name = av_default_item_name,
598  .option = options,
599  .version = LIBAVUTIL_VERSION_INT,
600 };
601 
604  .name = "x11grab",
605  .long_name = NULL_IF_CONFIG_SMALL("X11grab"),
606  .priv_data_size = sizeof(struct x11_grab),
607  .read_header = x11grab_read_header,
608  .read_packet = x11grab_read_packet,
609  .read_close = x11grab_read_close,
610  .flags = AVFMT_NOFILE,
611  .priv_class = &x11_class,
612 };