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/demux.h"
  33 #include "libavformat/internal.h"
  34 #include "libavutil/mem.h"
  35 #include "libavutil/opt.h"
  36 #include "libavutil/time.h"
  37 #include "libavutil/wchar_filename.h"
  38 #include <windows.h>
  39
  40 /**
  41  * GDI Device Demuxer context
  42  */
  43 struct gdigrab {
  44     const AVClass *class;   /**< Class for private options */
  45
  46     int        frame_size;  /**< Size in bytes of the frame pixel data */
  47     int        header_size; /**< Size in bytes of the DIB header */
  48     AVRational time_base;   /**< Time base */
  49     int64_t    time_frame;  /**< Current time */
  50
  51     int        draw_mouse;  /**< Draw mouse cursor (private option) */
  52     int        show_region; /**< Draw border (private option) */
  53     AVRational framerate;   /**< Capture framerate (private option) */
  54     int        width;       /**< Width of the grab frame (private option) */
  55     int        height;      /**< Height of the grab frame (private option) */
  56     int        offset_x;    /**< Capture x offset (private option) */
  57     int        offset_y;    /**< Capture y offset (private option) */
  58
  59     HWND       hwnd;        /**< Handle of the window for the grab */
  60     HDC        source_hdc;  /**< Source device context */
  61     HDC        dest_hdc;    /**< Destination, source-compatible DC */
  62     BITMAPINFO bmi;         /**< Information describing DIB format */
  63     HBITMAP    hbmp;        /**< Information on the bitmap captured */
  64     void      *buffer;      /**< The buffer containing the bitmap image data */
  65     RECT       clip_rect;   /**< The subarea of the screen or window to clip */
  66
  67     HWND       region_hwnd; /**< Handle of the region border window */
  68
  69     int cursor_error_printed;
  70 };
  71
  72 #define WIN32_API_ERROR(str)                                            \
  73     av_log(s1, AV_LOG_ERROR, str " (error %li)\n", GetLastError())
  74
  75 #define REGION_WND_BORDER 3
  76
  77 /**
  78  * Callback to handle Windows messages for the region outline window.
  79  *
  80  * In particular, this handles painting the frame rectangle.
  81  *
  82  * @param hwnd The region outline window handle.
  83  * @param msg The Windows message.
  84  * @param wparam First Windows message parameter.
  85  * @param lparam Second Windows message parameter.
  86  * @return 0 success, !0 failure
  87  */
  88 static LRESULT CALLBACK
  89 gdigrab_region_wnd_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
  90 {
  91     PAINTSTRUCT ps;
  92     HDC hdc;
  93     RECT rect;
  94
  95     switch (msg) {
  96     case WM_PAINT:
  97         hdc = BeginPaint(hwnd, &ps);
  98
  99         GetClientRect(hwnd, &rect);
 100         FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
 101
 102         rect.left++; rect.top++; rect.right--; rect.bottom--;
 103         FrameRect(hdc, &rect, GetStockObject(WHITE_BRUSH));
 104
 105         rect.left++; rect.top++; rect.right--; rect.bottom--;
 106         FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
 107
 108         EndPaint(hwnd, &ps);
 109         break;
 110     default:
 111         return DefWindowProc(hwnd, msg, wparam, lparam);
 112     }
 113     return 0;
 114 }
 115
 116 /**
 117  * Initialize the region outline window.
 118  *
 119  * @param s1 The format context.
 120  * @param gdigrab gdigrab context.
 121  * @return 0 success, !0 failure
 122  */
 123 static int
 124 gdigrab_region_wnd_init(AVFormatContext *s1, struct gdigrab *gdigrab)
 125 {
 126     HWND hwnd;
 127     RECT rect = gdigrab->clip_rect;
 128     HRGN region = NULL;
 129     HRGN region_interior = NULL;
 130
 131     DWORD style = WS_POPUP | WS_VISIBLE;
 132     DWORD ex = WS_EX_TOOLWINDOW | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
 133
 134     rect.left -= REGION_WND_BORDER; rect.top -= REGION_WND_BORDER;
 135     rect.right += REGION_WND_BORDER; rect.bottom += REGION_WND_BORDER;
 136
 137     AdjustWindowRectEx(&rect, style, FALSE, ex);
 138
 139     // Create a window with no owner; use WC_DIALOG instead of writing a custom
 140     // window class
 141     hwnd = CreateWindowEx(ex, WC_DIALOG, NULL, style, rect.left, rect.top,
 142             rect.right - rect.left, rect.bottom - rect.top,
 143             NULL, NULL, NULL, NULL);
 144     if (!hwnd) {
 145         WIN32_API_ERROR("Could not create region display window");
 146         goto error;
 147     }
 148
 149     // Set the window shape to only include the border area
 150     GetClientRect(hwnd, &rect);
 151     region = CreateRectRgn(0, 0,
 152             rect.right - rect.left, rect.bottom - rect.top);
 153     region_interior = CreateRectRgn(REGION_WND_BORDER, REGION_WND_BORDER,
 154             rect.right - rect.left - REGION_WND_BORDER,
 155             rect.bottom - rect.top - REGION_WND_BORDER);
 156     CombineRgn(region, region, region_interior, RGN_DIFF);
 157     if (!SetWindowRgn(hwnd, region, FALSE)) {
 158         WIN32_API_ERROR("Could not set window region");
 159         goto error;
 160     }
 161     // The "region" memory is now owned by the window
 162     region = NULL;
 163     DeleteObject(region_interior);
 164
 165     SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR) gdigrab_region_wnd_proc);
 166
 167     ShowWindow(hwnd, SW_SHOW);
 168
 169     gdigrab->region_hwnd = hwnd;
 170
 171     return 0;
 172
 173 error:
 174     if (region)
 175         DeleteObject(region);
 176     if (region_interior)
 177         DeleteObject(region_interior);
 178     if (hwnd)
 179         DestroyWindow(hwnd);
 180     return 1;
 181 }
 182
 183 /**
 184  * Cleanup/free the region outline window.
 185  *
 186  * @param s1 The format context.
 187  * @param gdigrab gdigrab context.
 188  */
 189 static void
 190 gdigrab_region_wnd_destroy(AVFormatContext *s1, struct gdigrab *gdigrab)
 191 {
 192     if (gdigrab->region_hwnd)
 193         DestroyWindow(gdigrab->region_hwnd);
 194     gdigrab->region_hwnd = NULL;
 195 }
 196
 197 /**
 198  * Process the Windows message queue.
 199  *
 200  * This is important to prevent Windows from thinking the window has become
 201  * unresponsive. As well, things like WM_PAINT (to actually draw the window
 202  * contents) are handled from the message queue context.
 203  *
 204  * @param s1 The format context.
 205  * @param gdigrab gdigrab context.
 206  */
 207 static void
 208 gdigrab_region_wnd_update(AVFormatContext *s1, struct gdigrab *gdigrab)
 209 {
 210     HWND hwnd = gdigrab->region_hwnd;
 211     MSG msg;
 212
 213     while (PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE)) {
 214         DispatchMessage(&msg);
 215     }
 216 }
 217
 218 /**
 219  * Initializes the gdi grab device demuxer (public device demuxer API).
 220  *
 221  * @param s1 Context from avformat core
 222  * @return AVERROR_IO error, 0 success
 223  */
 224 static int
 225 gdigrab_read_header(AVFormatContext *s1)
 226 {
 227     struct gdigrab *gdigrab = s1->priv_data;
 228
 229     HWND hwnd;
 230     HDC source_hdc = NULL;
 231     HDC dest_hdc   = NULL;
 232     BITMAPINFO bmi;
 233     HBITMAP hbmp   = NULL;
 234     void *buffer   = NULL;
 235
 236     const char *filename = s1->url;
 237     const char *name     = NULL;
 238     AVStream   *st       = NULL;
 239
 240     int bpp;
 241     int horzres;
 242     int vertres;
 243     int desktophorzres;
 244     int desktopvertres;
 245     RECT virtual_rect;
 246     RECT clip_rect;
 247     BITMAP bmp;
 248     int ret;
 249
 250     if (!strncmp(filename, "title=", 6)) {
 251         wchar_t *name_w = NULL;
 252         name = filename + 6;
 253
 254         if(utf8towchar(name, &name_w)) {
 255             ret = AVERROR(errno);
 256             goto error;
 257         }
 258         if(!name_w) {
 259             ret = AVERROR(EINVAL);
 260             goto error;
 261         }
 262
 263         hwnd = FindWindowW(NULL, name_w);
 264         av_freep(&name_w);
 265         if (!hwnd) {
 266             av_log(s1, AV_LOG_ERROR,
 267                    "Can't find window '%s', aborting.\n", name);
 268             ret = AVERROR(EIO);
 269             goto error;
 270         }
 271         if (gdigrab->show_region) {
 272             av_log(s1, AV_LOG_WARNING,
 273                     "Can't show region when grabbing a window.\n");
 274             gdigrab->show_region = 0;
 275         }
 276     } else if (!strcmp(filename, "desktop")) {
 277         hwnd = NULL;
 278     } else if (!strncmp(filename, "hwnd=", 5)) {
 279         char *p;
 280         name = filename + 5;
 281
 282         hwnd = (HWND) strtoull(name, &p, 0);
 283
 284         if (p == NULL || p == name || p[0] != '\0')
 285         {
 286             av_log(s1, AV_LOG_ERROR,
 287                    "Invalid window handle '%s', must be a valid integer.\n", name);
 288             ret = AVERROR(EINVAL);
 289             goto error;
 290         }
 291     } else {
 292         av_log(s1, AV_LOG_ERROR,
 293                "Please use \"desktop\", \"title=<windowname>\" or \"hwnd=<hwnd>\" to specify your target.\n");
 294         ret = AVERROR(EIO);
 295         goto error;
 296     }
 297
 298     /* This will get the device context for the selected window, or if
 299      * none, the primary screen */
 300     source_hdc = GetDC(hwnd);
 301     if (!source_hdc) {
 302         WIN32_API_ERROR("Couldn't get window device context");
 303         ret = AVERROR(EIO);
 304         goto error;
 305     }
 306     bpp = GetDeviceCaps(source_hdc, BITSPIXEL);
 307
 308     horzres = GetDeviceCaps(source_hdc, HORZRES);
 309     vertres = GetDeviceCaps(source_hdc, VERTRES);
 310     desktophorzres = GetDeviceCaps(source_hdc, DESKTOPHORZRES);
 311     desktopvertres = GetDeviceCaps(source_hdc, DESKTOPVERTRES);
 312
 313     if (hwnd) {
 314         GetClientRect(hwnd, &virtual_rect);
 315         /* window -- get the right height and width for scaling DPI */
 316         virtual_rect.left   = virtual_rect.left   * desktophorzres / horzres;
 317         virtual_rect.right  = virtual_rect.right  * desktophorzres / horzres;
 318         virtual_rect.top    = virtual_rect.top    * desktopvertres / vertres;
 319         virtual_rect.bottom = virtual_rect.bottom * desktopvertres / vertres;
 320     } else {
 321         /* desktop -- get the right height and width for scaling DPI */
 322         virtual_rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
 323         virtual_rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
 324         virtual_rect.right = (virtual_rect.left + GetSystemMetrics(SM_CXVIRTUALSCREEN)) * desktophorzres / horzres;
 325         virtual_rect.bottom = (virtual_rect.top + GetSystemMetrics(SM_CYVIRTUALSCREEN)) * desktopvertres / vertres;
 326     }
 327
 328     /* If no width or height set, use full screen/window area */
 329     if (!gdigrab->width || !gdigrab->height) {
 330         clip_rect.left = virtual_rect.left;
 331         clip_rect.top = virtual_rect.top;
 332         clip_rect.right = virtual_rect.right;
 333         clip_rect.bottom = virtual_rect.bottom;
 334     } else {
 335         clip_rect.left = gdigrab->offset_x;
 336         clip_rect.top = gdigrab->offset_y;
 337         clip_rect.right = gdigrab->width + gdigrab->offset_x;
 338         clip_rect.bottom = gdigrab->height + gdigrab->offset_y;
 339     }
 340
 341     if (clip_rect.left < virtual_rect.left ||
 342             clip_rect.top < virtual_rect.top ||
 343             clip_rect.right > virtual_rect.right ||
 344             clip_rect.bottom > virtual_rect.bottom) {
 345             av_log(s1, AV_LOG_ERROR,
 346                     "Capture area (%li,%li),(%li,%li) extends outside window area (%li,%li),(%li,%li)",
 347                     clip_rect.left, clip_rect.top,
 348                     clip_rect.right, clip_rect.bottom,
 349                     virtual_rect.left, virtual_rect.top,
 350                     virtual_rect.right, virtual_rect.bottom);
 351             ret = AVERROR(EIO);
 352             goto error;
 353     }
 354
 355
 356     if (name) {
 357         av_log(s1, AV_LOG_INFO,
 358                "Found window %s, capturing %lix%lix%i at (%li,%li)\n",
 359                name,
 360                clip_rect.right - clip_rect.left,
 361                clip_rect.bottom - clip_rect.top,
 362                bpp, clip_rect.left, clip_rect.top);
 363     } else {
 364         av_log(s1, AV_LOG_INFO,
 365                "Capturing whole desktop as %lix%lix%i at (%li,%li)\n",
 366                clip_rect.right - clip_rect.left,
 367                clip_rect.bottom - clip_rect.top,
 368                bpp, clip_rect.left, clip_rect.top);
 369     }
 370
 371     if (clip_rect.right - clip_rect.left <= 0 ||
 372             clip_rect.bottom - clip_rect.top <= 0 || bpp%8) {
 373         av_log(s1, AV_LOG_ERROR, "Invalid properties, aborting\n");
 374         ret = AVERROR(EIO);
 375         goto error;
 376     }
 377
 378     dest_hdc = CreateCompatibleDC(source_hdc);
 379     if (!dest_hdc) {
 380         WIN32_API_ERROR("Screen DC CreateCompatibleDC");
 381         ret = AVERROR(EIO);
 382         goto error;
 383     }
 384
 385     /* Create a DIB and select it into the dest_hdc */
 386     bmi.bmiHeader.biSize          = sizeof(BITMAPINFOHEADER);
 387     bmi.bmiHeader.biWidth         = clip_rect.right - clip_rect.left;
 388     bmi.bmiHeader.biHeight        = -(clip_rect.bottom - clip_rect.top);
 389     bmi.bmiHeader.biPlanes        = 1;
 390     bmi.bmiHeader.biBitCount      = bpp;
 391     bmi.bmiHeader.biCompression   = BI_RGB;
 392     bmi.bmiHeader.biSizeImage     = 0;
 393     bmi.bmiHeader.biXPelsPerMeter = 0;
 394     bmi.bmiHeader.biYPelsPerMeter = 0;
 395     bmi.bmiHeader.biClrUsed       = 0;
 396     bmi.bmiHeader.biClrImportant  = 0;
 397     hbmp = CreateDIBSection(dest_hdc, &bmi, DIB_RGB_COLORS,
 398             &buffer, NULL, 0);
 399     if (!hbmp) {
 400         WIN32_API_ERROR("Creating DIB Section");
 401         ret = AVERROR(EIO);
 402         goto error;
 403     }
 404
 405     if (!SelectObject(dest_hdc, hbmp)) {
 406         WIN32_API_ERROR("SelectObject");
 407         ret = AVERROR(EIO);
 408         goto error;
 409     }
 410
 411     /* Get info from the bitmap */
 412     GetObject(hbmp, sizeof(BITMAP), &bmp);
 413
 414     st = avformat_new_stream(s1, NULL);
 415     if (!st) {
 416         ret = AVERROR(ENOMEM);
 417         goto error;
 418     }
 419     avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
 420
 421     gdigrab->frame_size  = bmp.bmWidthBytes * bmp.bmHeight * bmp.bmPlanes;
 422     gdigrab->header_size = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
 423                            (bpp <= 8 ? (1 << bpp) : 0) * sizeof(RGBQUAD) /* palette size */;
 424     gdigrab->time_base   = av_inv_q(gdigrab->framerate);
 425     gdigrab->time_frame  = av_gettime_relative() / av_q2d(gdigrab->time_base);
 426
 427     gdigrab->hwnd       = hwnd;
 428     gdigrab->source_hdc = source_hdc;
 429     gdigrab->dest_hdc   = dest_hdc;
 430     gdigrab->hbmp       = hbmp;
 431     gdigrab->bmi        = bmi;
 432     gdigrab->buffer     = buffer;
 433     gdigrab->clip_rect  = clip_rect;
 434
 435     gdigrab->cursor_error_printed = 0;
 436
 437     if (gdigrab->show_region) {
 438         if (gdigrab_region_wnd_init(s1, gdigrab)) {
 439             ret = AVERROR(EIO);
 440             goto error;
 441         }
 442     }
 443
 444     st->avg_frame_rate = av_inv_q(gdigrab->time_base);
 445
 446     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 447     st->codecpar->codec_id   = AV_CODEC_ID_BMP;
 448     st->codecpar->bit_rate   = (gdigrab->header_size + gdigrab->frame_size) * 1/av_q2d(gdigrab->time_base) * 8;
 449
 450     return 0;
 451
 452 error:
 453     if (source_hdc)
 454         ReleaseDC(hwnd, source_hdc);
 455     if (dest_hdc)
 456         DeleteDC(dest_hdc);
 457     if (hbmp)
 458         DeleteObject(hbmp);
 459     if (source_hdc)
 460         DeleteDC(source_hdc);
 461     return ret;
 462 }
 463
 464 /**
 465  * Paints a mouse pointer in a Win32 image.
 466  *
 467  * @param s1 Context of the log information
 468  * @param s  Current grad structure
 469  */
 470 static void paint_mouse_pointer(AVFormatContext *s1, struct gdigrab *gdigrab)
 471 {
 472     CURSORINFO ci = {0};
 473
 474 #define CURSOR_ERROR(str)                 \
 475     if (!gdigrab->cursor_error_printed) {       \
 476         WIN32_API_ERROR(str);             \
 477         gdigrab->cursor_error_printed = 1;      \
 478     }
 479
 480     ci.cbSize = sizeof(ci);
 481
 482     if (GetCursorInfo(&ci)) {
 483         HCURSOR icon = CopyCursor(ci.hCursor);
 484         ICONINFO info;
 485         POINT pos;
 486         RECT clip_rect = gdigrab->clip_rect;
 487         HWND hwnd = gdigrab->hwnd;
 488         int horzres = GetDeviceCaps(gdigrab->source_hdc, HORZRES);
 489         int vertres = GetDeviceCaps(gdigrab->source_hdc, VERTRES);
 490         int desktophorzres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPHORZRES);
 491         int desktopvertres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPVERTRES);
 492         info.hbmMask = NULL;
 493         info.hbmColor = NULL;
 494
 495         if (ci.flags != CURSOR_SHOWING)
 496             return;
 497
 498         if (!icon) {
 499             /* Use the standard arrow cursor as a fallback.
 500              * You'll probably only hit this in Wine, which can't fetch
 501              * the current system cursor. */
 502             icon = CopyCursor(LoadCursor(NULL, IDC_ARROW));
 503         }
 504
 505         if (!GetIconInfo(icon, &info)) {
 506             CURSOR_ERROR("Could not get icon info");
 507             goto icon_error;
 508         }
 509
 510         if (hwnd) {
 511             RECT rect;
 512
 513             if (GetWindowRect(hwnd, &rect)) {
 514                 pos.x = ci.ptScreenPos.x - clip_rect.left - info.xHotspot - rect.left;
 515                 pos.y = ci.ptScreenPos.y - clip_rect.top - info.yHotspot - rect.top;
 516
 517                 //that would keep the correct location of mouse with hidpi screens
 518                 pos.x = pos.x * desktophorzres / horzres;
 519                 pos.y = pos.y * desktopvertres / vertres;
 520             } else {
 521                 CURSOR_ERROR("Couldn't get window rectangle");
 522                 goto icon_error;
 523             }
 524         } else {
 525             //that would keep the correct location of mouse with hidpi screens
 526             pos.x = ci.ptScreenPos.x * desktophorzres / horzres - clip_rect.left - info.xHotspot;
 527             pos.y = ci.ptScreenPos.y * desktopvertres / vertres - clip_rect.top - info.yHotspot;
 528         }
 529
 530         av_log(s1, AV_LOG_DEBUG, "Cursor pos (%li,%li) -> (%li,%li)\n",
 531                 ci.ptScreenPos.x, ci.ptScreenPos.y, pos.x, pos.y);
 532
 533         if (pos.x >= 0 && pos.x <= clip_rect.right - clip_rect.left &&
 534                 pos.y >= 0 && pos.y <= clip_rect.bottom - clip_rect.top) {
 535             if (!DrawIcon(gdigrab->dest_hdc, pos.x, pos.y, icon))
 536                 CURSOR_ERROR("Couldn't draw icon");
 537         }
 538
 539 icon_error:
 540         if (info.hbmMask)
 541             DeleteObject(info.hbmMask);
 542         if (info.hbmColor)
 543             DeleteObject(info.hbmColor);
 544         if (icon)
 545             DestroyCursor(icon);
 546     } else {
 547         CURSOR_ERROR("Couldn't get cursor info");
 548     }
 549 }
 550
 551 /**
 552  * Grabs a frame from gdi (public device demuxer API).
 553  *
 554  * @param s1 Context from avformat core
 555  * @param pkt Packet holding the grabbed frame
 556  * @return frame size in bytes
 557  */
 558 static int gdigrab_read_packet(AVFormatContext *s1, AVPacket *pkt)
 559 {
 560     struct gdigrab *gdigrab = s1->priv_data;
 561
 562     HDC        dest_hdc   = gdigrab->dest_hdc;
 563     HDC        source_hdc = gdigrab->source_hdc;
 564     RECT       clip_rect  = gdigrab->clip_rect;
 565     AVRational time_base  = gdigrab->time_base;
 566     int64_t    time_frame = gdigrab->time_frame;
 567
 568     BITMAPFILEHEADER bfh;
 569     int file_size = gdigrab->header_size + gdigrab->frame_size;
 570
 571     int64_t curtime, delay;
 572
 573     /* Calculate the time of the next frame */
 574     time_frame += INT64_C(1000000);
 575
 576     /* Run Window message processing queue */
 577     if (gdigrab->show_region)
 578         gdigrab_region_wnd_update(s1, gdigrab);
 579
 580     /* wait based on the frame rate */
 581     for (;;) {
 582         curtime = av_gettime_relative();
 583         delay = time_frame * av_q2d(time_base) - curtime;
 584         if (delay <= 0) {
 585             if (delay < INT64_C(-1000000) * av_q2d(time_base)) {
 586                 time_frame += INT64_C(1000000);
 587             }
 588             break;
 589         }
 590         if (s1->flags & AVFMT_FLAG_NONBLOCK) {
 591             return AVERROR(EAGAIN);
 592         } else {
 593             av_usleep(delay);
 594         }
 595     }
 596
 597     if (av_new_packet(pkt, file_size) < 0)
 598         return AVERROR(ENOMEM);
 599     pkt->pts = av_gettime();
 600
 601     /* Blit screen grab */
 602     if (!BitBlt(dest_hdc, 0, 0,
 603                 clip_rect.right - clip_rect.left,
 604                 clip_rect.bottom - clip_rect.top,
 605                 source_hdc,
 606                 clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
 607         WIN32_API_ERROR("Failed to capture image");
 608         return AVERROR(EIO);
 609     }
 610     if (gdigrab->draw_mouse)
 611         paint_mouse_pointer(s1, gdigrab);
 612
 613     /* Copy bits to packet data */
 614
 615     bfh.bfType = 0x4d42; /* "BM" in little-endian */
 616     bfh.bfSize = file_size;
 617     bfh.bfReserved1 = 0;
 618     bfh.bfReserved2 = 0;
 619     bfh.bfOffBits = gdigrab->header_size;
 620
 621     memcpy(pkt->data, &bfh, sizeof(bfh));
 622
 623     memcpy(pkt->data + sizeof(bfh), &gdigrab->bmi.bmiHeader, sizeof(gdigrab->bmi.bmiHeader));
 624
 625     if (gdigrab->bmi.bmiHeader.biBitCount <= 8)
 626         GetDIBColorTable(dest_hdc, 0, 1 << gdigrab->bmi.bmiHeader.biBitCount,
 627                 (RGBQUAD *) (pkt->data + sizeof(bfh) + sizeof(gdigrab->bmi.bmiHeader)));
 628
 629     memcpy(pkt->data + gdigrab->header_size, gdigrab->buffer, gdigrab->frame_size);
 630
 631     gdigrab->time_frame = time_frame;
 632
 633     return gdigrab->header_size + gdigrab->frame_size;
 634 }
 635
 636 /**
 637  * Closes gdi frame grabber (public device demuxer API).
 638  *
 639  * @param s1 Context from avformat core
 640  * @return 0 success, !0 failure
 641  */
 642 static int gdigrab_read_close(AVFormatContext *s1)
 643 {
 644     struct gdigrab *s = s1->priv_data;
 645
 646     if (s->show_region)
 647         gdigrab_region_wnd_destroy(s1, s);
 648
 649     if (s->source_hdc)
 650         ReleaseDC(s->hwnd, s->source_hdc);
 651     if (s->dest_hdc)
 652         DeleteDC(s->dest_hdc);
 653     if (s->hbmp)
 654         DeleteObject(s->hbmp);
 655     if (s->source_hdc)
 656         DeleteDC(s->source_hdc);
 657
 658     return 0;
 659 }
 660
 661 #define OFFSET(x) offsetof(struct gdigrab, x)
 662 #define DEC AV_OPT_FLAG_DECODING_PARAM
 663 static const AVOption options[] = {
 664     { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
 665     { "show_region", "draw border around capture area", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
 666     { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, INT_MAX, DEC },
 667     { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
 668     { "offset_x", "capture area x offset", OFFSET(offset_x), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
 669     { "offset_y", "capture area y offset", OFFSET(offset_y), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
 670     { NULL },
 671 };
 672
 673 static const AVClass gdigrab_class = {
 674     .class_name = "GDIgrab indev",
 675     .item_name  = av_default_item_name,
 676     .option     = options,
 677     .version    = LIBAVUTIL_VERSION_INT,
 678     .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
 679 };
 680
 681 /** gdi grabber device demuxer declaration */
 682 const FFInputFormat ff_gdigrab_demuxer = {
 683     .p.name         = "gdigrab",
 684     .p.long_name    = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
 685     .p.flags        = AVFMT_NOFILE,
 686     .p.priv_class   = &gdigrab_class,
 687     .priv_data_size = sizeof(struct gdigrab),
 688     .read_header    = gdigrab_read_header,
 689     .read_packet    = gdigrab_read_packet,
 690     .read_close     = gdigrab_read_close,
 691 };