libavdevice/gdigrab.c

   1 /*
   2  * GDI video grab interface
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * Copyright (C) 2013 Calvin Walton <calvin.walton@kepstin.ca>
   7  * Copyright (C) 2007-2010 Christophe Gisquet <word1.word2@gmail.com>
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1
  12  * of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /**
  25  * @file
  26  * GDI frame device demuxer
  27  * @author Calvin Walton <calvin.walton@kepstin.ca>
  28  * @author Christophe Gisquet <word1.word2@gmail.com>
  29  */
  30
  31 #include "config.h"
  32 #include "libavformat/internal.h"
  33 #include "libavutil/opt.h"
  34 #include "libavutil/time.h"
  35 #include <windows.h>
  36
  37 /**
  38  * GDI Device Demuxer context
  39  */
  40 struct gdigrab {
  41     const AVClass *class;   /**< Class for private options */
  42
  43     int        frame_size;  /**< Size in bytes of the frame pixel data */
  44     int        header_size; /**< Size in bytes of the DIB header */
  45     AVRational time_base;   /**< Time base */
  46     int64_t    time_frame;  /**< Current time */
  47
  48     int        draw_mouse;  /**< Draw mouse cursor (private option) */
  49     int        show_region; /**< Draw border (private option) */
  50     AVRational framerate;   /**< Capture framerate (private option) */
  51     int        width;       /**< Width of the grab frame (private option) */
  52     int        height;      /**< Height of the grab frame (private option) */
  53     int        offset_x;    /**< Capture x offset (private option) */
  54     int        offset_y;    /**< Capture y offset (private option) */
  55
  56     HWND       hwnd;        /**< Handle of the window for the grab */
  57     HDC        source_hdc;  /**< Source device context */
  58     HDC        dest_hdc;    /**< Destination, source-compatible DC */
  59     BITMAPINFO bmi;         /**< Information describing DIB format */
  60     HBITMAP    hbmp;        /**< Information on the bitmap captured */
  61     void      *buffer;      /**< The buffer containing the bitmap image data */
  62     RECT       clip_rect;   /**< The subarea of the screen or window to clip */
  63
  64     HWND       region_hwnd; /**< Handle of the region border window */
  65
  66     int cursor_error_printed;
  67 };
  68
  69 #define WIN32_API_ERROR(str)                                            \
  70     av_log(s1, AV_LOG_ERROR, str " (error %li)\n", GetLastError())
  71
  72 #define REGION_WND_BORDER 3
  73
  74 /**
  75  * Callback to handle Windows messages for the region outline window.
  76  *
  77  * In particular, this handles painting the frame rectangle.
  78  *
  79  * @param hwnd The region outline window handle.
  80  * @param msg The Windows message.
  81  * @param wparam First Windows message parameter.
  82  * @param lparam Second Windows message parameter.
  83  * @return 0 success, !0 failure
  84  */
  85 static LRESULT CALLBACK
  86 gdigrab_region_wnd_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
  87 {
  88     PAINTSTRUCT ps;
  89     HDC hdc;
  90     RECT rect;
  91
  92     switch (msg) {
  93     case WM_PAINT:
  94         hdc = BeginPaint(hwnd, &ps);
  95
  96         GetClientRect(hwnd, &rect);
  97         FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
  98
  99         rect.left++; rect.top++; rect.right--; rect.bottom--;
 100         FrameRect(hdc, &rect, GetStockObject(WHITE_BRUSH));
 101
 102         rect.left++; rect.top++; rect.right--; rect.bottom--;
 103         FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
 104
 105         EndPaint(hwnd, &ps);
 106         break;
 107     default:
 108         return DefWindowProc(hwnd, msg, wparam, lparam);
 109     }
 110     return 0;
 111 }
 112
 113 /**
 114  * Initialize the region outline window.
 115  *
 116  * @param s1 The format context.
 117  * @param gdigrab gdigrab context.
 118  * @return 0 success, !0 failure
 119  */
 120 static int
 121 gdigrab_region_wnd_init(AVFormatContext *s1, struct gdigrab *gdigrab)
 122 {
 123     HWND hwnd;
 124     RECT rect = gdigrab->clip_rect;
 125     HRGN region = NULL;
 126     HRGN region_interior = NULL;
 127
 128     DWORD style = WS_POPUP | WS_VISIBLE;
 129     DWORD ex = WS_EX_TOOLWINDOW | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
 130
 131     rect.left -= REGION_WND_BORDER; rect.top -= REGION_WND_BORDER;
 132     rect.right += REGION_WND_BORDER; rect.bottom += REGION_WND_BORDER;
 133
 134     AdjustWindowRectEx(&rect, style, FALSE, ex);
 135
 136     // Create a window with no owner; use WC_DIALOG instead of writing a custom
 137     // window class
 138     hwnd = CreateWindowEx(ex, WC_DIALOG, NULL, style, rect.left, rect.top,
 139             rect.right - rect.left, rect.bottom - rect.top,
 140             NULL, NULL, NULL, NULL);
 141     if (!hwnd) {
 142         WIN32_API_ERROR("Could not create region display window");
 143         goto error;
 144     }
 145
 146     // Set the window shape to only include the border area
 147     GetClientRect(hwnd, &rect);
 148     region = CreateRectRgn(0, 0,
 149             rect.right - rect.left, rect.bottom - rect.top);
 150     region_interior = CreateRectRgn(REGION_WND_BORDER, REGION_WND_BORDER,
 151             rect.right - rect.left - REGION_WND_BORDER,
 152             rect.bottom - rect.top - REGION_WND_BORDER);
 153     CombineRgn(region, region, region_interior, RGN_DIFF);
 154     if (!SetWindowRgn(hwnd, region, FALSE)) {
 155         WIN32_API_ERROR("Could not set window region");
 156         goto error;
 157     }
 158     // The "region" memory is now owned by the window
 159     region = NULL;
 160     DeleteObject(region_interior);
 161
 162     SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR) gdigrab_region_wnd_proc);
 163
 164     ShowWindow(hwnd, SW_SHOW);
 165
 166     gdigrab->region_hwnd = hwnd;
 167
 168     return 0;
 169
 170 error:
 171     if (region)
 172         DeleteObject(region);
 173     if (region_interior)
 174         DeleteObject(region_interior);
 175     if (hwnd)
 176         DestroyWindow(hwnd);
 177     return 1;
 178 }
 179
 180 /**
 181  * Cleanup/free the region outline window.
 182  *
 183  * @param s1 The format context.
 184  * @param gdigrab gdigrab context.
 185  */
 186 static void
 187 gdigrab_region_wnd_destroy(AVFormatContext *s1, struct gdigrab *gdigrab)
 188 {
 189     if (gdigrab->region_hwnd)
 190         DestroyWindow(gdigrab->region_hwnd);
 191     gdigrab->region_hwnd = NULL;
 192 }
 193
 194 /**
 195  * Process the Windows message queue.
 196  *
 197  * This is important to prevent Windows from thinking the window has become
 198  * unresponsive. As well, things like WM_PAINT (to actually draw the window
 199  * contents) are handled from the message queue context.
 200  *
 201  * @param s1 The format context.
 202  * @param gdigrab gdigrab context.
 203  */
 204 static void
 205 gdigrab_region_wnd_update(AVFormatContext *s1, struct gdigrab *gdigrab)
 206 {
 207     HWND hwnd = gdigrab->region_hwnd;
 208     MSG msg;
 209
 210     while (PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE)) {
 211         DispatchMessage(&msg);
 212     }
 213 }
 214
 215 /**
 216  * Initializes the gdi grab device demuxer (public device demuxer API).
 217  *
 218  * @param s1 Context from avformat core
 219  * @return AVERROR_IO error, 0 success
 220  */
 221 static int
 222 gdigrab_read_header(AVFormatContext *s1)
 223 {
 224     struct gdigrab *gdigrab = s1->priv_data;
 225
 226     HWND hwnd;
 227     HDC source_hdc = NULL;
 228     HDC dest_hdc   = NULL;
 229     BITMAPINFO bmi;
 230     HBITMAP hbmp   = NULL;
 231     void *buffer   = NULL;
 232
 233     const char *filename = s1->url;
 234     const char *name     = NULL;
 235     AVStream   *st       = NULL;
 236
 237     int bpp;
 238     int horzres;
 239     int vertres;
 240     int desktophorzres;
 241     int desktopvertres;
 242     RECT virtual_rect;
 243     RECT clip_rect;
 244     BITMAP bmp;
 245     int ret;
 246
 247     if (!strncmp(filename, "title=", 6)) {
 248         name = filename + 6;
 249         hwnd = FindWindow(NULL, name);
 250         if (!hwnd) {
 251             av_log(s1, AV_LOG_ERROR,
 252                    "Can't find window '%s', aborting.\n", name);
 253             ret = AVERROR(EIO);
 254             goto error;
 255         }
 256         if (gdigrab->show_region) {
 257             av_log(s1, AV_LOG_WARNING,
 258                     "Can't show region when grabbing a window.\n");
 259             gdigrab->show_region = 0;
 260         }
 261     } else if (!strcmp(filename, "desktop")) {
 262         hwnd = NULL;
 263     } else {
 264         av_log(s1, AV_LOG_ERROR,
 265                "Please use \"desktop\" or \"title=<windowname>\" to specify your target.\n");
 266         ret = AVERROR(EIO);
 267         goto error;
 268     }
 269
 270     /* This will get the device context for the selected window, or if
 271      * none, the primary screen */
 272     source_hdc = GetDC(hwnd);
 273     if (!source_hdc) {
 274         WIN32_API_ERROR("Couldn't get window device context");
 275         ret = AVERROR(EIO);
 276         goto error;
 277     }
 278     bpp = GetDeviceCaps(source_hdc, BITSPIXEL);
 279
 280     horzres = GetDeviceCaps(source_hdc, HORZRES);
 281     vertres = GetDeviceCaps(source_hdc, VERTRES);
 282     desktophorzres = GetDeviceCaps(source_hdc, DESKTOPHORZRES);
 283     desktopvertres = GetDeviceCaps(source_hdc, DESKTOPVERTRES);
 284
 285     if (hwnd) {
 286         GetClientRect(hwnd, &virtual_rect);
 287         /* window -- get the right height and width for scaling DPI */
 288         virtual_rect.left   = virtual_rect.left   * desktophorzres / horzres;
 289         virtual_rect.right  = virtual_rect.right  * desktophorzres / horzres;
 290         virtual_rect.top    = virtual_rect.top    * desktopvertres / vertres;
 291         virtual_rect.bottom = virtual_rect.bottom * desktopvertres / vertres;
 292     } else {
 293         /* desktop -- get the right height and width for scaling DPI */
 294         virtual_rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
 295         virtual_rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
 296         virtual_rect.right = (virtual_rect.left + GetSystemMetrics(SM_CXVIRTUALSCREEN)) * desktophorzres / horzres;
 297         virtual_rect.bottom = (virtual_rect.top + GetSystemMetrics(SM_CYVIRTUALSCREEN)) * desktopvertres / vertres;
 298     }
 299
 300     /* If no width or height set, use full screen/window area */
 301     if (!gdigrab->width || !gdigrab->height) {
 302         clip_rect.left = virtual_rect.left;
 303         clip_rect.top = virtual_rect.top;
 304         clip_rect.right = virtual_rect.right;
 305         clip_rect.bottom = virtual_rect.bottom;
 306     } else {
 307         clip_rect.left = gdigrab->offset_x;
 308         clip_rect.top = gdigrab->offset_y;
 309         clip_rect.right = gdigrab->width + gdigrab->offset_x;
 310         clip_rect.bottom = gdigrab->height + gdigrab->offset_y;
 311     }
 312
 313     if (clip_rect.left < virtual_rect.left ||
 314             clip_rect.top < virtual_rect.top ||
 315             clip_rect.right > virtual_rect.right ||
 316             clip_rect.bottom > virtual_rect.bottom) {
 317             av_log(s1, AV_LOG_ERROR,
 318                     "Capture area (%li,%li),(%li,%li) extends outside window area (%li,%li),(%li,%li)",
 319                     clip_rect.left, clip_rect.top,
 320                     clip_rect.right, clip_rect.bottom,
 321                     virtual_rect.left, virtual_rect.top,
 322                     virtual_rect.right, virtual_rect.bottom);
 323             ret = AVERROR(EIO);
 324             goto error;
 325     }
 326
 327
 328     if (name) {
 329         av_log(s1, AV_LOG_INFO,
 330                "Found window %s, capturing %lix%lix%i at (%li,%li)\n",
 331                name,
 332                clip_rect.right - clip_rect.left,
 333                clip_rect.bottom - clip_rect.top,
 334                bpp, clip_rect.left, clip_rect.top);
 335     } else {
 336         av_log(s1, AV_LOG_INFO,
 337                "Capturing whole desktop as %lix%lix%i at (%li,%li)\n",
 338                clip_rect.right - clip_rect.left,
 339                clip_rect.bottom - clip_rect.top,
 340                bpp, clip_rect.left, clip_rect.top);
 341     }
 342
 343     if (clip_rect.right - clip_rect.left <= 0 ||
 344             clip_rect.bottom - clip_rect.top <= 0 || bpp%8) {
 345         av_log(s1, AV_LOG_ERROR, "Invalid properties, aborting\n");
 346         ret = AVERROR(EIO);
 347         goto error;
 348     }
 349
 350     dest_hdc = CreateCompatibleDC(source_hdc);
 351     if (!dest_hdc) {
 352         WIN32_API_ERROR("Screen DC CreateCompatibleDC");
 353         ret = AVERROR(EIO);
 354         goto error;
 355     }
 356
 357     /* Create a DIB and select it into the dest_hdc */
 358     bmi.bmiHeader.biSize          = sizeof(BITMAPINFOHEADER);
 359     bmi.bmiHeader.biWidth         = clip_rect.right - clip_rect.left;
 360     bmi.bmiHeader.biHeight        = -(clip_rect.bottom - clip_rect.top);
 361     bmi.bmiHeader.biPlanes        = 1;
 362     bmi.bmiHeader.biBitCount      = bpp;
 363     bmi.bmiHeader.biCompression   = BI_RGB;
 364     bmi.bmiHeader.biSizeImage     = 0;
 365     bmi.bmiHeader.biXPelsPerMeter = 0;
 366     bmi.bmiHeader.biYPelsPerMeter = 0;
 367     bmi.bmiHeader.biClrUsed       = 0;
 368     bmi.bmiHeader.biClrImportant  = 0;
 369     hbmp = CreateDIBSection(dest_hdc, &bmi, DIB_RGB_COLORS,
 370             &buffer, NULL, 0);
 371     if (!hbmp) {
 372         WIN32_API_ERROR("Creating DIB Section");
 373         ret = AVERROR(EIO);
 374         goto error;
 375     }
 376
 377     if (!SelectObject(dest_hdc, hbmp)) {
 378         WIN32_API_ERROR("SelectObject");
 379         ret = AVERROR(EIO);
 380         goto error;
 381     }
 382
 383     /* Get info from the bitmap */
 384     GetObject(hbmp, sizeof(BITMAP), &bmp);
 385
 386     st = avformat_new_stream(s1, NULL);
 387     if (!st) {
 388         ret = AVERROR(ENOMEM);
 389         goto error;
 390     }
 391     avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
 392
 393     gdigrab->frame_size  = bmp.bmWidthBytes * bmp.bmHeight * bmp.bmPlanes;
 394     gdigrab->header_size = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
 395                            (bpp <= 8 ? (1 << bpp) : 0) * sizeof(RGBQUAD) /* palette size */;
 396     gdigrab->time_base   = av_inv_q(gdigrab->framerate);
 397     gdigrab->time_frame  = av_gettime() / av_q2d(gdigrab->time_base);
 398
 399     gdigrab->hwnd       = hwnd;
 400     gdigrab->source_hdc = source_hdc;
 401     gdigrab->dest_hdc   = dest_hdc;
 402     gdigrab->hbmp       = hbmp;
 403     gdigrab->bmi        = bmi;
 404     gdigrab->buffer     = buffer;
 405     gdigrab->clip_rect  = clip_rect;
 406
 407     gdigrab->cursor_error_printed = 0;
 408
 409     if (gdigrab->show_region) {
 410         if (gdigrab_region_wnd_init(s1, gdigrab)) {
 411             ret = AVERROR(EIO);
 412             goto error;
 413         }
 414     }
 415
 416     st->avg_frame_rate = av_inv_q(gdigrab->time_base);
 417
 418     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 419     st->codecpar->codec_id   = AV_CODEC_ID_BMP;
 420     st->codecpar->bit_rate   = (gdigrab->header_size + gdigrab->frame_size) * 1/av_q2d(gdigrab->time_base) * 8;
 421
 422     return 0;
 423
 424 error:
 425     if (source_hdc)
 426         ReleaseDC(hwnd, source_hdc);
 427     if (dest_hdc)
 428         DeleteDC(dest_hdc);
 429     if (hbmp)
 430         DeleteObject(hbmp);
 431     if (source_hdc)
 432         DeleteDC(source_hdc);
 433     return ret;
 434 }
 435
 436 /**
 437  * Paints a mouse pointer in a Win32 image.
 438  *
 439  * @param s1 Context of the log information
 440  * @param s  Current grad structure
 441  */
 442 static void paint_mouse_pointer(AVFormatContext *s1, struct gdigrab *gdigrab)
 443 {
 444     CURSORINFO ci = {0};
 445
 446 #define CURSOR_ERROR(str)                 \
 447     if (!gdigrab->cursor_error_printed) {       \
 448         WIN32_API_ERROR(str);             \
 449         gdigrab->cursor_error_printed = 1;      \
 450     }
 451
 452     ci.cbSize = sizeof(ci);
 453
 454     if (GetCursorInfo(&ci)) {
 455         HCURSOR icon = CopyCursor(ci.hCursor);
 456         ICONINFO info;
 457         POINT pos;
 458         RECT clip_rect = gdigrab->clip_rect;
 459         HWND hwnd = gdigrab->hwnd;
 460         int horzres = GetDeviceCaps(gdigrab->source_hdc, HORZRES);
 461         int vertres = GetDeviceCaps(gdigrab->source_hdc, VERTRES);
 462         int desktophorzres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPHORZRES);
 463         int desktopvertres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPVERTRES);
 464         info.hbmMask = NULL;
 465         info.hbmColor = NULL;
 466
 467         if (ci.flags != CURSOR_SHOWING)
 468             return;
 469
 470         if (!icon) {
 471             /* Use the standard arrow cursor as a fallback.
 472              * You'll probably only hit this in Wine, which can't fetch
 473              * the current system cursor. */
 474             icon = CopyCursor(LoadCursor(NULL, IDC_ARROW));
 475         }
 476
 477         if (!GetIconInfo(icon, &info)) {
 478             CURSOR_ERROR("Could not get icon info");
 479             goto icon_error;
 480         }
 481
 482         if (hwnd) {
 483             RECT rect;
 484
 485             if (GetWindowRect(hwnd, &rect)) {
 486                 pos.x = ci.ptScreenPos.x - clip_rect.left - info.xHotspot - rect.left;
 487                 pos.y = ci.ptScreenPos.y - clip_rect.top - info.yHotspot - rect.top;
 488
 489                 //that would keep the correct location of mouse with hidpi screens
 490                 pos.x = pos.x * desktophorzres / horzres;
 491                 pos.y = pos.y * desktopvertres / vertres;
 492             } else {
 493                 CURSOR_ERROR("Couldn't get window rectangle");
 494                 goto icon_error;
 495             }
 496         } else {
 497             //that would keep the correct location of mouse with hidpi screens
 498             pos.x = ci.ptScreenPos.x * desktophorzres / horzres - clip_rect.left - info.xHotspot;
 499             pos.y = ci.ptScreenPos.y * desktopvertres / vertres - clip_rect.top - info.yHotspot;
 500         }
 501
 502         av_log(s1, AV_LOG_DEBUG, "Cursor pos (%li,%li) -> (%li,%li)\n",
 503                 ci.ptScreenPos.x, ci.ptScreenPos.y, pos.x, pos.y);
 504
 505         if (pos.x >= 0 && pos.x <= clip_rect.right - clip_rect.left &&
 506                 pos.y >= 0 && pos.y <= clip_rect.bottom - clip_rect.top) {
 507             if (!DrawIcon(gdigrab->dest_hdc, pos.x, pos.y, icon))
 508                 CURSOR_ERROR("Couldn't draw icon");
 509         }
 510
 511 icon_error:
 512         if (info.hbmMask)
 513             DeleteObject(info.hbmMask);
 514         if (info.hbmColor)
 515             DeleteObject(info.hbmColor);
 516         if (icon)
 517             DestroyCursor(icon);
 518     } else {
 519         CURSOR_ERROR("Couldn't get cursor info");
 520     }
 521 }
 522
 523 /**
 524  * Grabs a frame from gdi (public device demuxer API).
 525  *
 526  * @param s1 Context from avformat core
 527  * @param pkt Packet holding the grabbed frame
 528  * @return frame size in bytes
 529  */
 530 static int gdigrab_read_packet(AVFormatContext *s1, AVPacket *pkt)
 531 {
 532     struct gdigrab *gdigrab = s1->priv_data;
 533
 534     HDC        dest_hdc   = gdigrab->dest_hdc;
 535     HDC        source_hdc = gdigrab->source_hdc;
 536     RECT       clip_rect  = gdigrab->clip_rect;
 537     AVRational time_base  = gdigrab->time_base;
 538     int64_t    time_frame = gdigrab->time_frame;
 539
 540     BITMAPFILEHEADER bfh;
 541     int file_size = gdigrab->header_size + gdigrab->frame_size;
 542
 543     int64_t curtime, delay;
 544
 545     /* Calculate the time of the next frame */
 546     time_frame += INT64_C(1000000);
 547
 548     /* Run Window message processing queue */
 549     if (gdigrab->show_region)
 550         gdigrab_region_wnd_update(s1, gdigrab);
 551
 552     /* wait based on the frame rate */
 553     for (;;) {
 554         curtime = av_gettime();
 555         delay = time_frame * av_q2d(time_base) - curtime;
 556         if (delay <= 0) {
 557             if (delay < INT64_C(-1000000) * av_q2d(time_base)) {
 558                 time_frame += INT64_C(1000000);
 559             }
 560             break;
 561         }
 562         if (s1->flags & AVFMT_FLAG_NONBLOCK) {
 563             return AVERROR(EAGAIN);
 564         } else {
 565             av_usleep(delay);
 566         }
 567     }
 568
 569     if (av_new_packet(pkt, file_size) < 0)
 570         return AVERROR(ENOMEM);
 571     pkt->pts = curtime;
 572
 573     /* Blit screen grab */
 574     if (!BitBlt(dest_hdc, 0, 0,
 575                 clip_rect.right - clip_rect.left,
 576                 clip_rect.bottom - clip_rect.top,
 577                 source_hdc,
 578                 clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
 579         WIN32_API_ERROR("Failed to capture image");
 580         return AVERROR(EIO);
 581     }
 582     if (gdigrab->draw_mouse)
 583         paint_mouse_pointer(s1, gdigrab);
 584
 585     /* Copy bits to packet data */
 586
 587     bfh.bfType = 0x4d42; /* "BM" in little-endian */
 588     bfh.bfSize = file_size;
 589     bfh.bfReserved1 = 0;
 590     bfh.bfReserved2 = 0;
 591     bfh.bfOffBits = gdigrab->header_size;
 592
 593     memcpy(pkt->data, &bfh, sizeof(bfh));
 594
 595     memcpy(pkt->data + sizeof(bfh), &gdigrab->bmi.bmiHeader, sizeof(gdigrab->bmi.bmiHeader));
 596
 597     if (gdigrab->bmi.bmiHeader.biBitCount <= 8)
 598         GetDIBColorTable(dest_hdc, 0, 1 << gdigrab->bmi.bmiHeader.biBitCount,
 599                 (RGBQUAD *) (pkt->data + sizeof(bfh) + sizeof(gdigrab->bmi.bmiHeader)));
 600
 601     memcpy(pkt->data + gdigrab->header_size, gdigrab->buffer, gdigrab->frame_size);
 602
 603     gdigrab->time_frame = time_frame;
 604
 605     return gdigrab->header_size + gdigrab->frame_size;
 606 }
 607
 608 /**
 609  * Closes gdi frame grabber (public device demuxer API).
 610  *
 611  * @param s1 Context from avformat core
 612  * @return 0 success, !0 failure
 613  */
 614 static int gdigrab_read_close(AVFormatContext *s1)
 615 {
 616     struct gdigrab *s = s1->priv_data;
 617
 618     if (s->show_region)
 619         gdigrab_region_wnd_destroy(s1, s);
 620
 621     if (s->source_hdc)
 622         ReleaseDC(s->hwnd, s->source_hdc);
 623     if (s->dest_hdc)
 624         DeleteDC(s->dest_hdc);
 625     if (s->hbmp)
 626         DeleteObject(s->hbmp);
 627     if (s->source_hdc)
 628         DeleteDC(s->source_hdc);
 629
 630     return 0;
 631 }
 632
 633 #define OFFSET(x) offsetof(struct gdigrab, 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     { "show_region", "draw border around capture area", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
 638     { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, INT_MAX, DEC },
 639     { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
 640     { "offset_x", "capture area x offset", OFFSET(offset_x), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
 641     { "offset_y", "capture area y offset", OFFSET(offset_y), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
 642     { NULL },
 643 };
 644
 645 static const AVClass gdigrab_class = {
 646     .class_name = "GDIgrab indev",
 647     .item_name  = av_default_item_name,
 648     .option     = options,
 649     .version    = LIBAVUTIL_VERSION_INT,
 650     .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
 651 };
 652
 653 /** gdi grabber device demuxer declaration */
 654 AVInputFormat ff_gdigrab_demuxer = {
 655     .name           = "gdigrab",
 656     .long_name      = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
 657     .priv_data_size = sizeof(struct gdigrab),
 658     .read_header    = gdigrab_read_header,
 659     .read_packet    = gdigrab_read_packet,
 660     .read_close     = gdigrab_read_close,
 661     .flags          = AVFMT_NOFILE,
 662     .priv_class     = &gdigrab_class,
 663 };