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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  char *framerate; /**< Set by a private option. */
80 
81  Window region_win; /**< This is used by show_region option. */
82 };
83 
84 #define REGION_WIN_BORDER 3
85 /**
86  * Draw grabbing region window
87  *
88  * @param s x11grab context
89  */
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 
110 /**
111  * Initialize grabbing region window
112  *
113  * @param s x11grab context
114  */
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 
145 /**
146  * Initialize the x11 grab device demuxer (public device demuxer API).
147  *
148  * @param s1 Context from avformat core
149  * @return <ul>
150  * <li>AVERROR(ENOMEM) no memory left</li>
151  * <li>AVERROR(EIO) other failure case</li>
152  * <li>0 success</li>
153  * </ul>
154  */
155 static int
157 {
158  struct x11grab *x11grab = s1->priv_data;
159  Display *dpy;
160  AVStream *st = NULL;
161  enum AVPixelFormat input_pixfmt;
162  XImage *image;
163  int x_off = 0;
164  int y_off = 0;
165  int screen;
166  int use_shm;
167  char *dpyname, *offset;
168  int ret = 0;
170 
171  dpyname = av_strdup(s1->filename);
172  if (!dpyname)
173  goto out;
174 
175  offset = strchr(dpyname, '+');
176  if (offset) {
177  sscanf(offset, "%d,%d", &x_off, &y_off);
178  if (strstr(offset, "nomouse")) {
180  "'nomouse' specification in argument is deprecated: "
181  "use 'draw_mouse' option with value 0 instead\n");
182  x11grab->draw_mouse = 0;
183  }
184  *offset= 0;
185  }
186 
187  if ((ret = av_parse_video_rate(&framerate, x11grab->framerate)) < 0) {
188  av_log(s1, AV_LOG_ERROR, "Could not parse framerate: %s.\n", x11grab->framerate);
189  goto out;
190  }
191  av_log(s1, AV_LOG_INFO, "device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
192  s1->filename, dpyname, x_off, y_off, x11grab->width, x11grab->height);
193 
194  dpy = XOpenDisplay(dpyname);
195  av_freep(&dpyname);
196  if(!dpy) {
197  av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
198  ret = AVERROR(EIO);
199  goto out;
200  }
201 
202  st = avformat_new_stream(s1, NULL);
203  if (!st) {
204  ret = AVERROR(ENOMEM);
205  goto out;
206  }
207  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
208 
209  screen = DefaultScreen(dpy);
210 
211  if (x11grab->follow_mouse) {
212  int screen_w, screen_h;
213  Window w;
214 
215  screen_w = DisplayWidth(dpy, screen);
216  screen_h = DisplayHeight(dpy, screen);
217  XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off, &ret, &ret, &ret);
218  x_off -= x11grab->width / 2;
219  y_off -= x11grab->height / 2;
220  x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
221  y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
222  av_log(s1, AV_LOG_INFO, "followmouse is enabled, resetting grabbing region to x: %d y: %d\n", x_off, y_off);
223  }
224 
225  use_shm = XShmQueryExtension(dpy);
226  av_log(s1, AV_LOG_INFO, "shared memory extension%s found\n", use_shm ? "" : " not");
227 
228  if(use_shm) {
229  int scr = XDefaultScreen(dpy);
230  image = XShmCreateImage(dpy,
231  DefaultVisual(dpy, scr),
232  DefaultDepth(dpy, scr),
233  ZPixmap,
234  NULL,
235  &x11grab->shminfo,
236  x11grab->width, x11grab->height);
237  x11grab->shminfo.shmid = shmget(IPC_PRIVATE,
238  image->bytes_per_line * image->height,
239  IPC_CREAT|0777);
240  if (x11grab->shminfo.shmid == -1) {
241  av_log(s1, AV_LOG_ERROR, "Fatal: Can't get shared memory!\n");
242  ret = AVERROR(ENOMEM);
243  goto out;
244  }
245  x11grab->shminfo.shmaddr = image->data = shmat(x11grab->shminfo.shmid, 0, 0);
246  x11grab->shminfo.readOnly = False;
247 
248  if (!XShmAttach(dpy, &x11grab->shminfo)) {
249  av_log(s1, AV_LOG_ERROR, "Fatal: Failed to attach shared memory!\n");
250  /* needs some better error subroutine :) */
251  ret = AVERROR(EIO);
252  goto out;
253  }
254  } else {
255  image = XGetImage(dpy, RootWindow(dpy, screen),
256  x_off,y_off,
257  x11grab->width, x11grab->height,
258  AllPlanes, ZPixmap);
259  }
260 
261  switch (image->bits_per_pixel) {
262  case 8:
263  av_log (s1, AV_LOG_DEBUG, "8 bit palette\n");
264  input_pixfmt = AV_PIX_FMT_PAL8;
265  break;
266  case 16:
267  if ( image->red_mask == 0xf800 &&
268  image->green_mask == 0x07e0 &&
269  image->blue_mask == 0x001f ) {
270  av_log (s1, AV_LOG_DEBUG, "16 bit RGB565\n");
271  input_pixfmt = AV_PIX_FMT_RGB565;
272  } else if (image->red_mask == 0x7c00 &&
273  image->green_mask == 0x03e0 &&
274  image->blue_mask == 0x001f ) {
275  av_log(s1, AV_LOG_DEBUG, "16 bit RGB555\n");
276  input_pixfmt = AV_PIX_FMT_RGB555;
277  } else {
278  av_log(s1, AV_LOG_ERROR, "RGB ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
279  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);
280  ret = AVERROR(EIO);
281  goto out;
282  }
283  break;
284  case 24:
285  if ( image->red_mask == 0xff0000 &&
286  image->green_mask == 0x00ff00 &&
287  image->blue_mask == 0x0000ff ) {
288  input_pixfmt = AV_PIX_FMT_BGR24;
289  } else if ( image->red_mask == 0x0000ff &&
290  image->green_mask == 0x00ff00 &&
291  image->blue_mask == 0xff0000 ) {
292  input_pixfmt = AV_PIX_FMT_RGB24;
293  } else {
294  av_log(s1, AV_LOG_ERROR,"rgb ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
295  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);
296  ret = AVERROR(EIO);
297  goto out;
298  }
299  break;
300  case 32:
301  input_pixfmt = AV_PIX_FMT_0RGB32;
302  break;
303  default:
304  av_log(s1, AV_LOG_ERROR, "image depth %i not supported ... aborting\n", image->bits_per_pixel);
305  ret = AVERROR(EINVAL);
306  goto out;
307  }
308 
309  x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel/8;
310  x11grab->dpy = dpy;
311  x11grab->time_base = av_inv_q(framerate);
312  x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
313  x11grab->x_off = x_off;
314  x11grab->y_off = y_off;
315  x11grab->image = image;
316  x11grab->use_shm = use_shm;
317 
320  st->codec->width = x11grab->width;
321  st->codec->height = x11grab->height;
322  st->codec->pix_fmt = input_pixfmt;
323  st->codec->time_base = x11grab->time_base;
324  st->codec->bit_rate = x11grab->frame_size * 1/av_q2d(x11grab->time_base) * 8;
325 
326 out:
327  av_free(dpyname);
328  return ret;
329 }
330 
331 /**
332  * Paint a mouse pointer in an X11 image.
333  *
334  * @param image image to paint the mouse pointer to
335  * @param s context used to retrieve original grabbing rectangle
336  * coordinates
337  */
338 static void
339 paint_mouse_pointer(XImage *image, struct x11grab *s)
340 {
341  int x_off = s->x_off;
342  int y_off = s->y_off;
343  int width = s->width;
344  int height = s->height;
345  Display *dpy = s->dpy;
346  XFixesCursorImage *xcim;
347  int x, y;
348  int line, column;
349  int to_line, to_column;
350  int pixstride = image->bits_per_pixel >> 3;
351  /* Warning: in its insanity, xlib provides unsigned image data through a
352  * char* pointer, so we have to make it uint8_t to make things not break.
353  * Anyone who performs further investigation of the xlib API likely risks
354  * permanent brain damage. */
355  uint8_t *pix = image->data;
356  Cursor c;
357  Window w;
358  XSetWindowAttributes attr;
359 
360  /* Code doesn't currently support 16-bit or PAL8 */
361  if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
362  return;
363 
364  c = XCreateFontCursor(dpy, XC_left_ptr);
365  w = DefaultRootWindow(dpy);
366  attr.cursor = c;
367  XChangeWindowAttributes(dpy, w, CWCursor, &attr);
368 
369  xcim = XFixesGetCursorImage(dpy);
370 
371  x = xcim->x - xcim->xhot;
372  y = xcim->y - xcim->yhot;
373 
374  to_line = FFMIN((y + xcim->height), (height + y_off));
375  to_column = FFMIN((x + xcim->width), (width + x_off));
376 
377  for (line = FFMAX(y, y_off); line < to_line; line++) {
378  for (column = FFMAX(x, x_off); column < to_column; column++) {
379  int xcim_addr = (line - y) * xcim->width + column - x;
380  int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
381  int r = (uint8_t)(xcim->pixels[xcim_addr] >> 0);
382  int g = (uint8_t)(xcim->pixels[xcim_addr] >> 8);
383  int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
384  int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);
385 
386  if (a == 255) {
387  pix[image_addr+0] = r;
388  pix[image_addr+1] = g;
389  pix[image_addr+2] = b;
390  } else if (a) {
391  /* pixel values from XFixesGetCursorImage come premultiplied by alpha */
392  pix[image_addr+0] = r + (pix[image_addr+0]*(255-a) + 255/2) / 255;
393  pix[image_addr+1] = g + (pix[image_addr+1]*(255-a) + 255/2) / 255;
394  pix[image_addr+2] = b + (pix[image_addr+2]*(255-a) + 255/2) / 255;
395  }
396  }
397  }
398 
399  XFree(xcim);
400  xcim = NULL;
401 }
402 
403 
404 /**
405  * Read new data in the image structure.
406  *
407  * @param dpy X11 display to grab from
408  * @param d
409  * @param image Image where the grab will be put
410  * @param x Top-Left grabbing rectangle horizontal coordinate
411  * @param y Top-Left grabbing rectangle vertical coordinate
412  * @return 0 if error, !0 if successful
413  */
414 static int
415 xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
416 {
417  xGetImageReply rep;
418  xGetImageReq *req;
419  long nbytes;
420 
421  if (!image) {
422  return 0;
423  }
424 
425  LockDisplay(dpy);
426  GetReq(GetImage, req);
427 
428  /* First set up the standard stuff in the request */
429  req->drawable = d;
430  req->x = x;
431  req->y = y;
432  req->width = image->width;
433  req->height = image->height;
434  req->planeMask = (unsigned int)AllPlanes;
435  req->format = ZPixmap;
436 
437  if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
438  UnlockDisplay(dpy);
439  SyncHandle();
440  return 0;
441  }
442 
443  nbytes = (long)rep.length << 2;
444  _XReadPad(dpy, image->data, nbytes);
445 
446  UnlockDisplay(dpy);
447  SyncHandle();
448  return 1;
449 }
450 
451 /**
452  * Grab a frame from x11 (public device demuxer API).
453  *
454  * @param s1 Context from avformat core
455  * @param pkt Packet holding the brabbed frame
456  * @return frame size in bytes
457  */
458 static int
460 {
461  struct x11grab *s = s1->priv_data;
462  Display *dpy = s->dpy;
463  XImage *image = s->image;
464  int x_off = s->x_off;
465  int y_off = s->y_off;
466 
467  int screen;
468  Window root;
469  int follow_mouse = s->follow_mouse;
470 
471  int64_t curtime, delay;
472  struct timespec ts;
473 
474  /* Calculate the time of the next frame */
475  s->time_frame += INT64_C(1000000);
476 
477  /* wait based on the frame rate */
478  for(;;) {
479  curtime = av_gettime();
480  delay = s->time_frame * av_q2d(s->time_base) - curtime;
481  if (delay <= 0) {
482  if (delay < INT64_C(-1000000) * av_q2d(s->time_base)) {
483  s->time_frame += INT64_C(1000000);
484  }
485  break;
486  }
487  ts.tv_sec = delay / 1000000;
488  ts.tv_nsec = (delay % 1000000) * 1000;
489  nanosleep(&ts, NULL);
490  }
491 
492  av_init_packet(pkt);
493  pkt->data = image->data;
494  pkt->size = s->frame_size;
495  pkt->pts = curtime;
496 
497  screen = DefaultScreen(dpy);
498  root = RootWindow(dpy, screen);
499  if (follow_mouse) {
500  int screen_w, screen_h;
501  int pointer_x, pointer_y, _;
502  Window w;
503 
504  screen_w = DisplayWidth(dpy, screen);
505  screen_h = DisplayHeight(dpy, screen);
506  XQueryPointer(dpy, root, &w, &w, &pointer_x, &pointer_y, &_, &_, &_);
507  if (follow_mouse == -1) {
508  // follow the mouse, put it at center of grabbing region
509  x_off += pointer_x - s->width / 2 - x_off;
510  y_off += pointer_y - s->height / 2 - y_off;
511  } else {
512  // follow the mouse, but only move the grabbing region when mouse
513  // reaches within certain pixels to the edge.
514  if (pointer_x > x_off + s->width - follow_mouse) {
515  x_off += pointer_x - (x_off + s->width - follow_mouse);
516  } else if (pointer_x < x_off + follow_mouse)
517  x_off -= (x_off + follow_mouse) - pointer_x;
518  if (pointer_y > y_off + s->height - follow_mouse) {
519  y_off += pointer_y - (y_off + s->height - follow_mouse);
520  } else if (pointer_y < y_off + follow_mouse)
521  y_off -= (y_off + follow_mouse) - pointer_y;
522  }
523  // adjust grabbing region position if it goes out of screen.
524  s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
525  s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);
526 
527  if (s->show_region && s->region_win)
528  XMoveWindow(dpy, s->region_win,
530  s->y_off - REGION_WIN_BORDER);
531  }
532 
533  if (s->show_region) {
534  if (s->region_win) {
535  XEvent evt;
536  // clean up the events, and do the initinal draw or redraw.
537  for (evt.type = NoEventMask; XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask, &evt); );
538  if (evt.type)
540  } else {
542  }
543  }
544 
545  if(s->use_shm) {
546  if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes)) {
547  av_log (s1, AV_LOG_INFO, "XShmGetImage() failed\n");
548  }
549  } else {
550  if (!xget_zpixmap(dpy, root, image, x_off, y_off)) {
551  av_log (s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
552  }
553  }
554 
555  if (s->draw_mouse) {
556  paint_mouse_pointer(image, s);
557  }
558 
559  return s->frame_size;
560 }
561 
562 /**
563  * Close x11 frame grabber (public device demuxer API).
564  *
565  * @param s1 Context from avformat core
566  * @return 0 success, !0 failure
567  */
568 static int
570 {
571  struct x11grab *x11grab = s1->priv_data;
572 
573  /* Detach cleanly from shared mem */
574  if (x11grab->use_shm) {
575  XShmDetach(x11grab->dpy, &x11grab->shminfo);
576  shmdt(x11grab->shminfo.shmaddr);
577  shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
578  }
579 
580  /* Destroy X11 image */
581  if (x11grab->image) {
582  XDestroyImage(x11grab->image);
583  x11grab->image = NULL;
584  }
585 
586  if (x11grab->region_win) {
587  XDestroyWindow(x11grab->dpy, x11grab->region_win);
588  }
589 
590  /* Free X11 display */
591  XCloseDisplay(x11grab->dpy);
592  return 0;
593 }
594 
595 #define OFFSET(x) offsetof(struct x11grab, x)
596 #define DEC AV_OPT_FLAG_DECODING_PARAM
597 static const AVOption options[] = {
598  { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
599 
600  { "follow_mouse", "move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region",
601  OFFSET(follow_mouse), AV_OPT_TYPE_INT, {.i64 = 0}, -1, INT_MAX, DEC, "follow_mouse" },
602  { "centered", "keep the mouse pointer at the center of grabbing region when following",
603  0, AV_OPT_TYPE_CONST, {.i64 = -1}, INT_MIN, INT_MAX, DEC, "follow_mouse" },
604 
605  { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc"}, 0, 0, DEC },
606  { "show_region", "show the grabbing region", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
607  { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = "vga"}, 0, 0, DEC },
608  { NULL },
609 };
610 
611 static const AVClass x11_class = {
612  .class_name = "X11grab indev",
613  .item_name = av_default_item_name,
614  .option = options,
615  .version = LIBAVUTIL_VERSION_INT,
616 };
617 
618 /** x11 grabber device demuxer declaration */
620  .name = "x11grab",
621  .long_name = NULL_IF_CONFIG_SMALL("X11grab"),
622  .priv_data_size = sizeof(struct x11grab),
623  .read_header = x11grab_read_header,
624  .read_packet = x11grab_read_packet,
625  .read_close = x11grab_read_close,
626  .flags = AVFMT_NOFILE,
627  .priv_class = &x11_class,
628 };