2 * GDI video grab interface
4 * This file is part of FFmpeg.
6 * Copyright (C) 2013 Calvin Walton <calvin.walton@kepstin.ca>
7 * Copyright (C) 2007-2010 Christophe Gisquet <word1.word2@gmail.com>
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.
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.
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
26 * GDI frame device demuxer
27 * @author Calvin Walton <calvin.walton@kepstin.ca>
28 * @author Christophe Gisquet <word1.word2@gmail.com>
32 #include "libavformat/internal.h"
33 #include "libavutil/opt.h"
34 #include "libavutil/time.h"
38 * GDI Device Demuxer context
41 const AVClass *class; /**< Class for private options */
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 */
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) */
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 */
64 HWND region_hwnd; /**< Handle of the region border window */
66 int cursor_error_printed;
69 #define WIN32_API_ERROR(str) \
70 av_log(s1, AV_LOG_ERROR, str " (error %li)\n", GetLastError())
72 #define REGION_WND_BORDER 3
75 * Callback to handle Windows messages for the region outline window.
77 * In particular, this handles painting the frame rectangle.
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
85 static LRESULT CALLBACK
86 gdigrab_region_wnd_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
94 hdc = BeginPaint(hwnd, &ps);
96 GetClientRect(hwnd, &rect);
97 FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
99 rect.left++; rect.top++; rect.right--; rect.bottom--;
100 FrameRect(hdc, &rect, GetStockObject(WHITE_BRUSH));
102 rect.left++; rect.top++; rect.right--; rect.bottom--;
103 FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
108 return DefWindowProc(hwnd, msg, wparam, lparam);
114 * Initialize the region outline window.
116 * @param s1 The format context.
117 * @param gdigrab gdigrab context.
118 * @return 0 success, !0 failure
121 gdigrab_region_wnd_init(AVFormatContext *s1, struct gdigrab *gdigrab)
124 RECT rect = gdigrab->clip_rect;
126 HRGN region_interior = NULL;
128 DWORD style = WS_POPUP | WS_VISIBLE;
129 DWORD ex = WS_EX_TOOLWINDOW | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
131 rect.left -= REGION_WND_BORDER; rect.top -= REGION_WND_BORDER;
132 rect.right += REGION_WND_BORDER; rect.bottom += REGION_WND_BORDER;
134 AdjustWindowRectEx(&rect, style, FALSE, ex);
136 // Create a window with no owner; use WC_DIALOG instead of writing a custom
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);
142 WIN32_API_ERROR("Could not create region display window");
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");
158 // The "region" memory is now owned by the window
160 DeleteObject(region_interior);
162 SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR) gdigrab_region_wnd_proc);
164 ShowWindow(hwnd, SW_SHOW);
166 gdigrab->region_hwnd = hwnd;
172 DeleteObject(region);
174 DeleteObject(region_interior);
181 * Cleanup/free the region outline window.
183 * @param s1 The format context.
184 * @param gdigrab gdigrab context.
187 gdigrab_region_wnd_destroy(AVFormatContext *s1, struct gdigrab *gdigrab)
189 if (gdigrab->region_hwnd)
190 DestroyWindow(gdigrab->region_hwnd);
191 gdigrab->region_hwnd = NULL;
195 * Process the Windows message queue.
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.
201 * @param s1 The format context.
202 * @param gdigrab gdigrab context.
205 gdigrab_region_wnd_update(AVFormatContext *s1, struct gdigrab *gdigrab)
207 HWND hwnd = gdigrab->region_hwnd;
210 while (PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE)) {
211 DispatchMessage(&msg);
216 * Initializes the gdi grab device demuxer (public device demuxer API).
218 * @param s1 Context from avformat core
219 * @return AVERROR_IO error, 0 success
222 gdigrab_read_header(AVFormatContext *s1)
224 struct gdigrab *gdigrab = s1->priv_data;
227 HDC source_hdc = NULL;
233 const char *filename = s1->filename;
234 const char *name = NULL;
243 if (!strncmp(filename, "title=", 6)) {
245 hwnd = FindWindow(NULL, name);
247 av_log(s1, AV_LOG_ERROR,
248 "Can't find window '%s', aborting.\n", name);
252 if (gdigrab->show_region) {
253 av_log(s1, AV_LOG_WARNING,
254 "Can't show region when grabbing a window.\n");
255 gdigrab->show_region = 0;
257 } else if (!strcmp(filename, "desktop")) {
260 av_log(s1, AV_LOG_ERROR,
261 "Please use \"desktop\" or \"title=<windowname>\" to specify your target.\n");
267 GetClientRect(hwnd, &virtual_rect);
269 virtual_rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
270 virtual_rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
271 virtual_rect.right = virtual_rect.left + GetSystemMetrics(SM_CXVIRTUALSCREEN);
272 virtual_rect.bottom = virtual_rect.top + GetSystemMetrics(SM_CYVIRTUALSCREEN);
275 /* If no width or height set, use full screen/window area */
276 if (!gdigrab->width || !gdigrab->height) {
277 clip_rect.left = virtual_rect.left;
278 clip_rect.top = virtual_rect.top;
279 clip_rect.right = virtual_rect.right;
280 clip_rect.bottom = virtual_rect.bottom;
282 clip_rect.left = gdigrab->offset_x;
283 clip_rect.top = gdigrab->offset_y;
284 clip_rect.right = gdigrab->width + gdigrab->offset_x;
285 clip_rect.bottom = gdigrab->height + gdigrab->offset_y;
288 if (clip_rect.left < virtual_rect.left ||
289 clip_rect.top < virtual_rect.top ||
290 clip_rect.right > virtual_rect.right ||
291 clip_rect.bottom > virtual_rect.bottom) {
292 av_log(s1, AV_LOG_ERROR,
293 "Capture area (%li,%li),(%li,%li) extends outside window area (%li,%li),(%li,%li)",
294 clip_rect.left, clip_rect.top,
295 clip_rect.right, clip_rect.bottom,
296 virtual_rect.left, virtual_rect.top,
297 virtual_rect.right, virtual_rect.bottom);
302 /* This will get the device context for the selected window, or if
303 * none, the primary screen */
304 source_hdc = GetDC(hwnd);
306 WIN32_API_ERROR("Couldn't get window device context");
310 bpp = GetDeviceCaps(source_hdc, BITSPIXEL);
313 av_log(s1, AV_LOG_INFO,
314 "Found window %s, capturing %lix%lix%i at (%li,%li)\n",
316 clip_rect.right - clip_rect.left,
317 clip_rect.bottom - clip_rect.top,
318 bpp, clip_rect.left, clip_rect.top);
320 av_log(s1, AV_LOG_INFO,
321 "Capturing whole desktop as %lix%lix%i at (%li,%li)\n",
322 clip_rect.right - clip_rect.left,
323 clip_rect.bottom - clip_rect.top,
324 bpp, clip_rect.left, clip_rect.top);
327 if (clip_rect.right - clip_rect.left <= 0 ||
328 clip_rect.bottom - clip_rect.top <= 0 || bpp%8) {
329 av_log(s1, AV_LOG_ERROR, "Invalid properties, aborting\n");
334 dest_hdc = CreateCompatibleDC(source_hdc);
336 WIN32_API_ERROR("Screen DC CreateCompatibleDC");
341 /* Create a DIB and select it into the dest_hdc */
342 bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
343 bmi.bmiHeader.biWidth = clip_rect.right - clip_rect.left;
344 bmi.bmiHeader.biHeight = -(clip_rect.bottom - clip_rect.top);
345 bmi.bmiHeader.biPlanes = 1;
346 bmi.bmiHeader.biBitCount = bpp;
347 bmi.bmiHeader.biCompression = BI_RGB;
348 bmi.bmiHeader.biSizeImage = 0;
349 bmi.bmiHeader.biXPelsPerMeter = 0;
350 bmi.bmiHeader.biYPelsPerMeter = 0;
351 bmi.bmiHeader.biClrUsed = 0;
352 bmi.bmiHeader.biClrImportant = 0;
353 hbmp = CreateDIBSection(dest_hdc, &bmi, DIB_RGB_COLORS,
356 WIN32_API_ERROR("Creating DIB Section");
361 if (!SelectObject(dest_hdc, hbmp)) {
362 WIN32_API_ERROR("SelectObject");
367 /* Get info from the bitmap */
368 GetObject(hbmp, sizeof(BITMAP), &bmp);
370 st = avformat_new_stream(s1, NULL);
372 ret = AVERROR(ENOMEM);
375 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
377 gdigrab->frame_size = bmp.bmWidthBytes * bmp.bmHeight * bmp.bmPlanes;
378 gdigrab->header_size = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
379 (bpp <= 8 ? (1 << bpp) : 0) * sizeof(RGBQUAD) /* palette size */;
380 gdigrab->time_base = av_inv_q(gdigrab->framerate);
381 gdigrab->time_frame = av_gettime() / av_q2d(gdigrab->time_base);
383 gdigrab->hwnd = hwnd;
384 gdigrab->source_hdc = source_hdc;
385 gdigrab->dest_hdc = dest_hdc;
386 gdigrab->hbmp = hbmp;
388 gdigrab->buffer = buffer;
389 gdigrab->clip_rect = clip_rect;
391 gdigrab->cursor_error_printed = 0;
393 if (gdigrab->show_region) {
394 if (gdigrab_region_wnd_init(s1, gdigrab)) {
400 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
401 st->codec->codec_id = AV_CODEC_ID_BMP;
402 st->codec->time_base = gdigrab->time_base;
403 st->codec->bit_rate = (gdigrab->header_size + gdigrab->frame_size) * 1/av_q2d(gdigrab->time_base) * 8;
409 ReleaseDC(hwnd, source_hdc);
415 DeleteDC(source_hdc);
420 * Paints a mouse pointer in a Win32 image.
422 * @param s1 Context of the log information
423 * @param s Current grad structure
425 static void paint_mouse_pointer(AVFormatContext *s1, struct gdigrab *gdigrab)
429 #define CURSOR_ERROR(str) \
430 if (!gdigrab->cursor_error_printed) { \
431 WIN32_API_ERROR(str); \
432 gdigrab->cursor_error_printed = 1; \
435 ci.cbSize = sizeof(ci);
437 if (GetCursorInfo(&ci)) {
438 HCURSOR icon = CopyCursor(ci.hCursor);
441 RECT clip_rect = gdigrab->clip_rect;
442 HWND hwnd = gdigrab->hwnd;
444 if (ci.flags != CURSOR_SHOWING)
448 /* Use the standard arrow cursor as a fallback.
449 * You'll probably only hit this in Wine, which can't fetch
450 * the current system cursor. */
451 icon = CopyCursor(LoadCursor(NULL, IDC_ARROW));
454 if (!GetIconInfo(icon, &info)) {
455 CURSOR_ERROR("Could not get icon info");
459 pos.x = ci.ptScreenPos.x - clip_rect.left - info.xHotspot;
460 pos.y = ci.ptScreenPos.y - clip_rect.top - info.yHotspot;
465 if (GetWindowRect(hwnd, &rect)) {
469 CURSOR_ERROR("Couldn't get window rectangle");
474 av_log(s1, AV_LOG_DEBUG, "Cursor pos (%li,%li) -> (%li,%li)\n",
475 ci.ptScreenPos.x, ci.ptScreenPos.y, pos.x, pos.y);
477 if (pos.x >= 0 && pos.x <= clip_rect.right - clip_rect.left &&
478 pos.y >= 0 && pos.y <= clip_rect.bottom - clip_rect.top) {
479 if (!DrawIcon(gdigrab->dest_hdc, pos.x, pos.y, icon))
480 CURSOR_ERROR("Couldn't draw icon");
487 CURSOR_ERROR("Couldn't get cursor info");
492 * Grabs a frame from gdi (public device demuxer API).
494 * @param s1 Context from avformat core
495 * @param pkt Packet holding the grabbed frame
496 * @return frame size in bytes
498 static int gdigrab_read_packet(AVFormatContext *s1, AVPacket *pkt)
500 struct gdigrab *gdigrab = s1->priv_data;
502 HDC dest_hdc = gdigrab->dest_hdc;
503 HDC source_hdc = gdigrab->source_hdc;
504 RECT clip_rect = gdigrab->clip_rect;
505 AVRational time_base = gdigrab->time_base;
506 int64_t time_frame = gdigrab->time_frame;
508 BITMAPFILEHEADER bfh;
509 int file_size = gdigrab->header_size + gdigrab->frame_size;
511 int64_t curtime, delay;
513 /* Calculate the time of the next frame */
514 time_frame += INT64_C(1000000);
516 /* Run Window message processing queue */
517 if (gdigrab->show_region)
518 gdigrab_region_wnd_update(s1, gdigrab);
520 /* wait based on the frame rate */
522 curtime = av_gettime();
523 delay = time_frame * av_q2d(time_base) - curtime;
525 if (delay < INT64_C(-1000000) * av_q2d(time_base)) {
526 time_frame += INT64_C(1000000);
530 if (s1->flags & AVFMT_FLAG_NONBLOCK) {
531 return AVERROR(EAGAIN);
537 if (av_new_packet(pkt, file_size) < 0)
538 return AVERROR(ENOMEM);
541 /* Blit screen grab */
542 if (!BitBlt(dest_hdc, 0, 0,
543 clip_rect.right - clip_rect.left,
544 clip_rect.bottom - clip_rect.top,
546 clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
547 WIN32_API_ERROR("Failed to capture image");
550 if (gdigrab->draw_mouse)
551 paint_mouse_pointer(s1, gdigrab);
553 /* Copy bits to packet data */
555 bfh.bfType = 0x4d42; /* "BM" in little-endian */
556 bfh.bfSize = file_size;
559 bfh.bfOffBits = gdigrab->header_size;
561 memcpy(pkt->data, &bfh, sizeof(bfh));
563 memcpy(pkt->data + sizeof(bfh), &gdigrab->bmi.bmiHeader, sizeof(gdigrab->bmi.bmiHeader));
565 if (gdigrab->bmi.bmiHeader.biBitCount <= 8)
566 GetDIBColorTable(dest_hdc, 0, 1 << gdigrab->bmi.bmiHeader.biBitCount,
567 (RGBQUAD *) (pkt->data + sizeof(bfh) + sizeof(gdigrab->bmi.bmiHeader)));
569 memcpy(pkt->data + gdigrab->header_size, gdigrab->buffer, gdigrab->frame_size);
571 gdigrab->time_frame = time_frame;
573 return gdigrab->header_size + gdigrab->frame_size;
577 * Closes gdi frame grabber (public device demuxer API).
579 * @param s1 Context from avformat core
580 * @return 0 success, !0 failure
582 static int gdigrab_read_close(AVFormatContext *s1)
584 struct gdigrab *s = s1->priv_data;
587 gdigrab_region_wnd_destroy(s1, s);
590 ReleaseDC(s->hwnd, s->source_hdc);
592 DeleteDC(s->dest_hdc);
594 DeleteObject(s->hbmp);
596 DeleteDC(s->source_hdc);
601 #define OFFSET(x) offsetof(struct gdigrab, x)
602 #define DEC AV_OPT_FLAG_DECODING_PARAM
603 static const AVOption options[] = {
604 { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
605 { "show_region", "draw border around capture area", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
606 { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, 0, DEC },
607 { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
608 { "offset_x", "capture area x offset", OFFSET(offset_x), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
609 { "offset_y", "capture area y offset", OFFSET(offset_y), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
613 static const AVClass gdigrab_class = {
614 .class_name = "GDIgrab indev",
615 .item_name = av_default_item_name,
617 .version = LIBAVUTIL_VERSION_INT,
620 /** gdi grabber device demuxer declaration */
621 AVInputFormat ff_gdigrab_demuxer = {
623 .long_name = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
624 .priv_data_size = sizeof(struct gdigrab),
625 .read_header = gdigrab_read_header,
626 .read_packet = gdigrab_read_packet,
627 .read_close = gdigrab_read_close,
628 .flags = AVFMT_NOFILE,
629 .priv_class = &gdigrab_class,