summaryrefslogtreecommitdiff
path: root/libavdevice/x11grab.c
blob: 14232ed0b7a29f9bdaa06282a910a1344f3837b9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
/*
 * X11 video grab interface
 *
 * This file is part of Libav.
 *
 * Libav integration:
 * Copyright (C) 2006 Clemens Fruhwirth <clemens@endorphin.org>
 *                    Edouard Gomez <ed.gomez@free.fr>
 *
 * This file contains code from grab.c:
 * Copyright (c) 2000-2001 Fabrice Bellard
 *
 * This file contains code from the xvidcap project:
 * Copyright (C) 1997-1998 Rasca, Berlin
 *               2003-2004 Karl H. Beckers, Frankfurt
 *
 * Libav is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * X11 frame device demuxer by Clemens Fruhwirth <clemens@endorphin.org>
 * and Edouard Gomez <ed.gomez@free.fr>.
 */

#include "config.h"
#include "libavformat/avformat.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include <time.h>
#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/Xlibint.h>
#include <X11/Xproto.h>
#include <X11/Xutil.h>
#include <sys/shm.h>
#include <X11/extensions/shape.h>
#include <X11/extensions/XShm.h>
#include <X11/extensions/Xfixes.h>

/**
 * X11 Device Demuxer context
 */
struct x11_grab
{
    const AVClass *class;    /**< Class for private options. */
    int frame_size;          /**< Size in bytes of a grabbed frame */
    AVRational time_base;    /**< Time base */
    int64_t time_frame;      /**< Current time */

    char *video_size;        /**< String describing video size, set by a private option. */
    int height;              /**< Height of the grab frame */
    int width;               /**< Width of the grab frame */
    int x_off;               /**< Horizontal top-left corner coordinate */
    int y_off;               /**< Vertical top-left corner coordinate */

    Display *dpy;            /**< X11 display from which x11grab grabs frames */
    XImage *image;           /**< X11 image holding the grab */
    int use_shm;             /**< !0 when using XShm extension */
    XShmSegmentInfo shminfo; /**< When using XShm, keeps track of XShm infos */
    int  draw_mouse;         /**< Set by a private option. */
    int  follow_mouse;       /**< Set by a private option. */
    int  show_region;        /**< set by a private option. */
    char *framerate;         /**< Set by a private option. */

    Window region_win;       /**< This is used by show_region option. */
};

#define REGION_WIN_BORDER 3
/**
 * Draw grabbing region window
 *
 * @param s x11_grab context
 */
static void
x11grab_draw_region_win(struct x11_grab *s)
{
    Display *dpy = s->dpy;
    int screen;
    Window win = s->region_win;
    GC gc;

    screen = DefaultScreen(dpy);
    gc = XCreateGC(dpy, win, 0, 0);
    XSetForeground(dpy, gc, WhitePixel(dpy, screen));
    XSetBackground(dpy, gc, BlackPixel(dpy, screen));
    XSetLineAttributes(dpy, gc, REGION_WIN_BORDER, LineDoubleDash, 0, 0);
    XDrawRectangle(dpy, win, gc,
                   1, 1,
                   (s->width  + REGION_WIN_BORDER * 2) - 1 * 2 - 1,
                   (s->height + REGION_WIN_BORDER * 2) - 1 * 2 - 1);
    XFreeGC(dpy, gc);
}

/**
 * Initialize grabbing region window
 *
 * @param s x11_grab context
 */
static void
x11grab_region_win_init(struct x11_grab *s)
{
    Display *dpy = s->dpy;
    int screen;
    XSetWindowAttributes attribs;
    XRectangle rect;

    screen = DefaultScreen(dpy);
    attribs.override_redirect = True;
    s->region_win = XCreateWindow(dpy, RootWindow(dpy, screen),
                                  s->x_off  - REGION_WIN_BORDER,
                                  s->y_off  - REGION_WIN_BORDER,
                                  s->width  + REGION_WIN_BORDER * 2,
                                  s->height + REGION_WIN_BORDER * 2,
                                  0, CopyFromParent,
                                  InputOutput, CopyFromParent,
                                  CWOverrideRedirect, &attribs);
    rect.x = 0;
    rect.y = 0;
    rect.width  = s->width;
    rect.height = s->height;
    XShapeCombineRectangles(dpy, s->region_win,
                            ShapeBounding, REGION_WIN_BORDER, REGION_WIN_BORDER,
                            &rect, 1, ShapeSubtract, 0);
    XMapWindow(dpy, s->region_win);
    XSelectInput(dpy, s->region_win, ExposureMask | StructureNotifyMask);
    x11grab_draw_region_win(s);
}

/**
 * Initialize the x11 grab device demuxer (public device demuxer API).
 *
 * @param s1 Context from avformat core
 * @param ap Parameters from avformat core
 * @return <ul>
 *          <li>AVERROR(ENOMEM) no memory left</li>
 *          <li>AVERROR(EIO) other failure case</li>
 *          <li>0 success</li>
 *         </ul>
 */
static int
x11grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
{
    struct x11_grab *x11grab = s1->priv_data;
    Display *dpy;
    AVStream *st = NULL;
    enum PixelFormat input_pixfmt;
    XImage *image;
    int x_off = 0;
    int y_off = 0;
    int screen;
    int use_shm;
    char *param, *offset;
    int ret = 0;
    AVRational framerate;

    param = av_strdup(s1->filename);
    offset = strchr(param, '+');
    if (offset) {
        sscanf(offset, "%d,%d", &x_off, &y_off);
        x11grab->draw_mouse = !strstr(offset, "nomouse");
        *offset= 0;
    }

    if ((ret = av_parse_video_size(&x11grab->width, &x11grab->height, x11grab->video_size)) < 0) {
        av_log(s1, AV_LOG_ERROR, "Couldn't parse video size.\n");
        goto out;
    }
    if ((ret = av_parse_video_rate(&framerate, x11grab->framerate)) < 0) {
        av_log(s1, AV_LOG_ERROR, "Could not parse framerate: %s.\n", x11grab->framerate);
        goto out;
    }
    av_log(s1, AV_LOG_INFO, "device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
           s1->filename, param, x_off, y_off, x11grab->width, x11grab->height);

    dpy = XOpenDisplay(param);
    if(!dpy) {
        av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
        ret = AVERROR(EIO);
        goto out;
    }

    st = av_new_stream(s1, 0);
    if (!st) {
        ret = AVERROR(ENOMEM);
        goto out;
    }
    av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */

    screen = DefaultScreen(dpy);

    if (x11grab->follow_mouse) {
        int screen_w, screen_h;
        Window w;

        screen_w = DisplayWidth(dpy, screen);
        screen_h = DisplayHeight(dpy, screen);
        XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off, &ret, &ret, &ret);
        x_off -= x11grab->width / 2;
        y_off -= x11grab->height / 2;
        x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
        y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
        av_log(s1, AV_LOG_INFO, "followmouse is enabled, resetting grabbing region to x: %d y: %d\n", x_off, y_off);
    }

    use_shm = XShmQueryExtension(dpy);
    av_log(s1, AV_LOG_INFO, "shared memory extension %s found\n", use_shm ? "" : "not");

    if(use_shm) {
        int scr = XDefaultScreen(dpy);
        image = XShmCreateImage(dpy,
                                DefaultVisual(dpy, scr),
                                DefaultDepth(dpy, scr),
                                ZPixmap,
                                NULL,
                                &x11grab->shminfo,
                                x11grab->width, x11grab->height);
        x11grab->shminfo.shmid = shmget(IPC_PRIVATE,
                                        image->bytes_per_line * image->height,
                                        IPC_CREAT|0777);
        if (x11grab->shminfo.shmid == -1) {
            av_log(s1, AV_LOG_ERROR, "Fatal: Can't get shared memory!\n");
            ret = AVERROR(ENOMEM);
            goto out;
        }
        x11grab->shminfo.shmaddr = image->data = shmat(x11grab->shminfo.shmid, 0, 0);
        x11grab->shminfo.readOnly = False;

        if (!XShmAttach(dpy, &x11grab->shminfo)) {
            av_log(s1, AV_LOG_ERROR, "Fatal: Failed to attach shared memory!\n");
            /* needs some better error subroutine :) */
            ret = AVERROR(EIO);
            goto out;
        }
    } else {
        image = XGetImage(dpy, RootWindow(dpy, screen),
                          x_off,y_off,
                          x11grab->width, x11grab->height,
                          AllPlanes, ZPixmap);
    }

    switch (image->bits_per_pixel) {
    case 8:
        av_log (s1, AV_LOG_DEBUG, "8 bit palette\n");
        input_pixfmt = PIX_FMT_PAL8;
        break;
    case 16:
        if (       image->red_mask   == 0xf800 &&
                   image->green_mask == 0x07e0 &&
                   image->blue_mask  == 0x001f ) {
            av_log (s1, AV_LOG_DEBUG, "16 bit RGB565\n");
            input_pixfmt = PIX_FMT_RGB565;
        } else if (image->red_mask   == 0x7c00 &&
                   image->green_mask == 0x03e0 &&
                   image->blue_mask  == 0x001f ) {
            av_log(s1, AV_LOG_DEBUG, "16 bit RGB555\n");
            input_pixfmt = PIX_FMT_RGB555;
        } else {
            av_log(s1, AV_LOG_ERROR, "RGB ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
            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);
            ret = AVERROR(EIO);
            goto out;
        }
        break;
    case 24:
        if (        image->red_mask   == 0xff0000 &&
                    image->green_mask == 0x00ff00 &&
                    image->blue_mask  == 0x0000ff ) {
            input_pixfmt = PIX_FMT_BGR24;
        } else if ( image->red_mask   == 0x0000ff &&
                    image->green_mask == 0x00ff00 &&
                    image->blue_mask  == 0xff0000 ) {
            input_pixfmt = PIX_FMT_RGB24;
        } else {
            av_log(s1, AV_LOG_ERROR,"rgb ordering at image depth %i not supported ... aborting\n", image->bits_per_pixel);
            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);
            ret = AVERROR(EIO);
            goto out;
        }
        break;
    case 32:
        input_pixfmt = PIX_FMT_RGB32;
        break;
    default:
        av_log(s1, AV_LOG_ERROR, "image depth %i not supported ... aborting\n", image->bits_per_pixel);
        ret = AVERROR(EINVAL);
        goto out;
    }

    x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel/8;
    x11grab->dpy = dpy;
    x11grab->time_base  = (AVRational){framerate.den, framerate.num};
    x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
    x11grab->x_off = x_off;
    x11grab->y_off = y_off;
    x11grab->image = image;
    x11grab->use_shm = use_shm;

    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codec->codec_id = CODEC_ID_RAWVIDEO;
    st->codec->width  = x11grab->width;
    st->codec->height = x11grab->height;
    st->codec->pix_fmt = input_pixfmt;
    st->codec->time_base = x11grab->time_base;
    st->codec->bit_rate = x11grab->frame_size * 1/av_q2d(x11grab->time_base) * 8;

out:
    return ret;
}

/**
 * Paint a mouse pointer in an X11 image.
 *
 * @param image image to paint the mouse pointer to
 * @param s context used to retrieve original grabbing rectangle
 *          coordinates
 */
static void
paint_mouse_pointer(XImage *image, struct x11_grab *s)
{
    int x_off = s->x_off;
    int y_off = s->y_off;
    int width = s->width;
    int height = s->height;
    Display *dpy = s->dpy;
    XFixesCursorImage *xcim;
    int x, y;
    int line, column;
    int to_line, to_column;
    int pixstride = image->bits_per_pixel >> 3;
    /* Warning: in its insanity, xlib provides unsigned image data through a
     * char* pointer, so we have to make it uint8_t to make things not break.
     * Anyone who performs further investigation of the xlib API likely risks
     * permanent brain damage. */
    uint8_t *pix = image->data;

    /* Code doesn't currently support 16-bit or PAL8 */
    if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
        return;

    xcim = XFixesGetCursorImage(dpy);

    x = xcim->x - xcim->xhot;
    y = xcim->y - xcim->yhot;

    to_line = FFMIN((y + xcim->height), (height + y_off));
    to_column = FFMIN((x + xcim->width), (width + x_off));

    for (line = FFMAX(y, y_off); line < to_line; line++) {
        for (column = FFMAX(x, x_off); column < to_column; column++) {
            int  xcim_addr = (line - y) * xcim->width + column - x;
            int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
            int r = (uint8_t)(xcim->pixels[xcim_addr] >>  0);
            int g = (uint8_t)(xcim->pixels[xcim_addr] >>  8);
            int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
            int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);

            if (a == 255) {
                pix[image_addr+0] = r;
                pix[image_addr+1] = g;
                pix[image_addr+2] = b;
            } else if (a) {
                /* pixel values from XFixesGetCursorImage come premultiplied by alpha */
                pix[image_addr+0] = r + (pix[image_addr+0]*(255-a) + 255/2) / 255;
                pix[image_addr+1] = g + (pix[image_addr+1]*(255-a) + 255/2) / 255;
                pix[image_addr+2] = b + (pix[image_addr+2]*(255-a) + 255/2) / 255;
            }
        }
    }

    XFree(xcim);
    xcim = NULL;
}


/**
 * Read new data in the image structure.
 *
 * @param dpy X11 display to grab from
 * @param d
 * @param image Image where the grab will be put
 * @param x Top-Left grabbing rectangle horizontal coordinate
 * @param y Top-Left grabbing rectangle vertical coordinate
 * @return 0 if error, !0 if successful
 */
static int
xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
{
    xGetImageReply rep;
    xGetImageReq *req;
    long nbytes;

    if (!image) {
        return 0;
    }

    LockDisplay(dpy);
    GetReq(GetImage, req);

    /* First set up the standard stuff in the request */
    req->drawable = d;
    req->x = x;
    req->y = y;
    req->width = image->width;
    req->height = image->height;
    req->planeMask = (unsigned int)AllPlanes;
    req->format = ZPixmap;

    if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
        UnlockDisplay(dpy);
        SyncHandle();
        return 0;
    }

    nbytes = (long)rep.length << 2;
    _XReadPad(dpy, image->data, nbytes);

    UnlockDisplay(dpy);
    SyncHandle();
    return 1;
}

/**
 * Grab a frame from x11 (public device demuxer API).
 *
 * @param s1 Context from avformat core
 * @param pkt Packet holding the brabbed frame
 * @return frame size in bytes
 */
static int
x11grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
{
    struct x11_grab *s = s1->priv_data;
    Display *dpy = s->dpy;
    XImage *image = s->image;
    int x_off = s->x_off;
    int y_off = s->y_off;

    int screen;
    Window root;
    int follow_mouse = s->follow_mouse;

    int64_t curtime, delay;
    struct timespec ts;

    /* Calculate the time of the next frame */
    s->time_frame += INT64_C(1000000);

    /* wait based on the frame rate */
    for(;;) {
        curtime = av_gettime();
        delay = s->time_frame * av_q2d(s->time_base) - curtime;
        if (delay <= 0) {
            if (delay < INT64_C(-1000000) * av_q2d(s->time_base)) {
                s->time_frame += INT64_C(1000000);
            }
            break;
        }
        ts.tv_sec = delay / 1000000;
        ts.tv_nsec = (delay % 1000000) * 1000;
        nanosleep(&ts, NULL);
    }

    av_init_packet(pkt);
    pkt->data = image->data;
    pkt->size = s->frame_size;
    pkt->pts = curtime;

    screen = DefaultScreen(dpy);
    root = RootWindow(dpy, screen);
    if (follow_mouse) {
        int screen_w, screen_h;
        int pointer_x, pointer_y, _;
        Window w;

        screen_w = DisplayWidth(dpy, screen);
        screen_h = DisplayHeight(dpy, screen);
        XQueryPointer(dpy, root, &w, &w, &pointer_x, &pointer_y, &_, &_, &_);
        if (follow_mouse == -1) {
            // follow the mouse, put it at center of grabbing region
            x_off += pointer_x - s->width  / 2 - x_off;
            y_off += pointer_y - s->height / 2 - y_off;
        } else {
            // follow the mouse, but only move the grabbing region when mouse
            // reaches within certain pixels to the edge.
            if (pointer_x > x_off + s->width - follow_mouse) {
                x_off += pointer_x - (x_off + s->width - follow_mouse);
            } else if (pointer_x < x_off + follow_mouse)
                x_off -= (x_off + follow_mouse) - pointer_x;
            if (pointer_y > y_off + s->height - follow_mouse) {
                y_off += pointer_y - (y_off + s->height - follow_mouse);
            } else if (pointer_y < y_off + follow_mouse)
                y_off -= (y_off + follow_mouse) - pointer_y;
        }
        // adjust grabbing region position if it goes out of screen.
        s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
        s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);

        if (s->show_region && s->region_win)
            XMoveWindow(dpy, s->region_win,
                        s->x_off - REGION_WIN_BORDER,
                        s->y_off - REGION_WIN_BORDER);
    }

    if (s->show_region) {
        if (s->region_win) {
            XEvent evt;
            // clean up the events, and do the initinal draw or redraw.
            for (evt.type = NoEventMask; XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask, &evt); );
            if (evt.type)
                x11grab_draw_region_win(s);
        } else {
            x11grab_region_win_init(s);
        }
    }

    if(s->use_shm) {
        if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes)) {
            av_log (s1, AV_LOG_INFO, "XShmGetImage() failed\n");
        }
    } else {
        if (!xget_zpixmap(dpy, root, image, x_off, y_off)) {
            av_log (s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
        }
    }

    if (s->draw_mouse) {
        paint_mouse_pointer(image, s);
    }

    return s->frame_size;
}

/**
 * Close x11 frame grabber (public device demuxer API).
 *
 * @param s1 Context from avformat core
 * @return 0 success, !0 failure
 */
static int
x11grab_read_close(AVFormatContext *s1)
{
    struct x11_grab *x11grab = s1->priv_data;

    /* Detach cleanly from shared mem */
    if (x11grab->use_shm) {
        XShmDetach(x11grab->dpy, &x11grab->shminfo);
        shmdt(x11grab->shminfo.shmaddr);
        shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
    }

    /* Destroy X11 image */
    if (x11grab->image) {
        XDestroyImage(x11grab->image);
        x11grab->image = NULL;
    }

    if (x11grab->region_win) {
        XDestroyWindow(x11grab->dpy, x11grab->region_win);
    }

    /* Free X11 display */
    XCloseDisplay(x11grab->dpy);
    return 0;
}

#define OFFSET(x) offsetof(struct x11_grab, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
    { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), AV_OPT_TYPE_STRING, {.str = "vga"}, 0, 0, DEC },
    { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc"}, 0, 0, DEC },
    { "draw_mouse", "Draw the mouse pointer.", OFFSET(draw_mouse), AV_OPT_TYPE_INT, { 1 }, 0, 1, DEC },
    { "follow_mouse", "Move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region.",
      OFFSET(follow_mouse), AV_OPT_TYPE_INT, { 0 }, -1, INT_MAX, DEC, "follow_mouse" },
    { "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" },
    { "show_region", "Show the grabbing region.", OFFSET(show_region), AV_OPT_TYPE_INT, { 0 }, 0, 1, DEC },
    { NULL },
};

static const AVClass x11_class = {
    .class_name = "X11grab indev",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

/** x11 grabber device demuxer declaration */
AVInputFormat ff_x11_grab_device_demuxer = {
    .name           = "x11grab",
    .long_name      = NULL_IF_CONFIG_SMALL("X11grab"),
    .priv_data_size = sizeof(struct x11_grab),
    .read_header    = x11grab_read_header,
    .read_packet    = x11grab_read_packet,
    .read_close     = x11grab_read_close,
    .flags          = AVFMT_NOFILE,
    .priv_class     = &x11_class,
};