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"
35 #include "libavutil/wchar_filename.h"
39 * GDI Device Demuxer context
42 const AVClass *class; /**< Class for private options */
44 int frame_size; /**< Size in bytes of the frame pixel data */
45 int header_size; /**< Size in bytes of the DIB header */
46 AVRational time_base; /**< Time base */
47 int64_t time_frame; /**< Current time */
49 int draw_mouse; /**< Draw mouse cursor (private option) */
50 int show_region; /**< Draw border (private option) */
51 AVRational framerate; /**< Capture framerate (private option) */
52 int width; /**< Width of the grab frame (private option) */
53 int height; /**< Height of the grab frame (private option) */
54 int offset_x; /**< Capture x offset (private option) */
55 int offset_y; /**< Capture y offset (private option) */
57 HWND hwnd; /**< Handle of the window for the grab */
58 HDC source_hdc; /**< Source device context */
59 HDC dest_hdc; /**< Destination, source-compatible DC */
60 BITMAPINFO bmi; /**< Information describing DIB format */
61 HBITMAP hbmp; /**< Information on the bitmap captured */
62 void *buffer; /**< The buffer containing the bitmap image data */
63 RECT clip_rect; /**< The subarea of the screen or window to clip */
65 HWND region_hwnd; /**< Handle of the region border window */
67 int cursor_error_printed;
70 #define WIN32_API_ERROR(str) \
71 av_log(s1, AV_LOG_ERROR, str " (error %li)\n", GetLastError())
73 #define REGION_WND_BORDER 3
76 * Callback to handle Windows messages for the region outline window.
78 * In particular, this handles painting the frame rectangle.
80 * @param hwnd The region outline window handle.
81 * @param msg The Windows message.
82 * @param wparam First Windows message parameter.
83 * @param lparam Second Windows message parameter.
84 * @return 0 success, !0 failure
86 static LRESULT CALLBACK
87 gdigrab_region_wnd_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
95 hdc = BeginPaint(hwnd, &ps);
97 GetClientRect(hwnd, &rect);
98 FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
100 rect.left++; rect.top++; rect.right--; rect.bottom--;
101 FrameRect(hdc, &rect, GetStockObject(WHITE_BRUSH));
103 rect.left++; rect.top++; rect.right--; rect.bottom--;
104 FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
109 return DefWindowProc(hwnd, msg, wparam, lparam);
115 * Initialize the region outline window.
117 * @param s1 The format context.
118 * @param gdigrab gdigrab context.
119 * @return 0 success, !0 failure
122 gdigrab_region_wnd_init(AVFormatContext *s1, struct gdigrab *gdigrab)
125 RECT rect = gdigrab->clip_rect;
127 HRGN region_interior = NULL;
129 DWORD style = WS_POPUP | WS_VISIBLE;
130 DWORD ex = WS_EX_TOOLWINDOW | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
132 rect.left -= REGION_WND_BORDER; rect.top -= REGION_WND_BORDER;
133 rect.right += REGION_WND_BORDER; rect.bottom += REGION_WND_BORDER;
135 AdjustWindowRectEx(&rect, style, FALSE, ex);
137 // Create a window with no owner; use WC_DIALOG instead of writing a custom
139 hwnd = CreateWindowEx(ex, WC_DIALOG, NULL, style, rect.left, rect.top,
140 rect.right - rect.left, rect.bottom - rect.top,
141 NULL, NULL, NULL, NULL);
143 WIN32_API_ERROR("Could not create region display window");
147 // Set the window shape to only include the border area
148 GetClientRect(hwnd, &rect);
149 region = CreateRectRgn(0, 0,
150 rect.right - rect.left, rect.bottom - rect.top);
151 region_interior = CreateRectRgn(REGION_WND_BORDER, REGION_WND_BORDER,
152 rect.right - rect.left - REGION_WND_BORDER,
153 rect.bottom - rect.top - REGION_WND_BORDER);
154 CombineRgn(region, region, region_interior, RGN_DIFF);
155 if (!SetWindowRgn(hwnd, region, FALSE)) {
156 WIN32_API_ERROR("Could not set window region");
159 // The "region" memory is now owned by the window
161 DeleteObject(region_interior);
163 SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR) gdigrab_region_wnd_proc);
165 ShowWindow(hwnd, SW_SHOW);
167 gdigrab->region_hwnd = hwnd;
173 DeleteObject(region);
175 DeleteObject(region_interior);
182 * Cleanup/free the region outline window.
184 * @param s1 The format context.
185 * @param gdigrab gdigrab context.
188 gdigrab_region_wnd_destroy(AVFormatContext *s1, struct gdigrab *gdigrab)
190 if (gdigrab->region_hwnd)
191 DestroyWindow(gdigrab->region_hwnd);
192 gdigrab->region_hwnd = NULL;
196 * Process the Windows message queue.
198 * This is important to prevent Windows from thinking the window has become
199 * unresponsive. As well, things like WM_PAINT (to actually draw the window
200 * contents) are handled from the message queue context.
202 * @param s1 The format context.
203 * @param gdigrab gdigrab context.
206 gdigrab_region_wnd_update(AVFormatContext *s1, struct gdigrab *gdigrab)
208 HWND hwnd = gdigrab->region_hwnd;
211 while (PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE)) {
212 DispatchMessage(&msg);
217 * Initializes the gdi grab device demuxer (public device demuxer API).
219 * @param s1 Context from avformat core
220 * @return AVERROR_IO error, 0 success
223 gdigrab_read_header(AVFormatContext *s1)
225 struct gdigrab *gdigrab = s1->priv_data;
228 HDC source_hdc = NULL;
234 const char *filename = s1->url;
235 const char *name = NULL;
248 if (!strncmp(filename, "title=", 6)) {
249 wchar_t *name_w = NULL;
252 if(utf8towchar(name, &name_w)) {
253 ret = AVERROR(errno);
257 ret = AVERROR(EINVAL);
261 hwnd = FindWindowW(NULL, name_w);
264 av_log(s1, AV_LOG_ERROR,
265 "Can't find window '%s', aborting.\n", name);
269 if (gdigrab->show_region) {
270 av_log(s1, AV_LOG_WARNING,
271 "Can't show region when grabbing a window.\n");
272 gdigrab->show_region = 0;
274 } else if (!strcmp(filename, "desktop")) {
277 av_log(s1, AV_LOG_ERROR,
278 "Please use \"desktop\" or \"title=<windowname>\" to specify your target.\n");
283 /* This will get the device context for the selected window, or if
284 * none, the primary screen */
285 source_hdc = GetDC(hwnd);
287 WIN32_API_ERROR("Couldn't get window device context");
291 bpp = GetDeviceCaps(source_hdc, BITSPIXEL);
293 horzres = GetDeviceCaps(source_hdc, HORZRES);
294 vertres = GetDeviceCaps(source_hdc, VERTRES);
295 desktophorzres = GetDeviceCaps(source_hdc, DESKTOPHORZRES);
296 desktopvertres = GetDeviceCaps(source_hdc, DESKTOPVERTRES);
299 GetClientRect(hwnd, &virtual_rect);
300 /* window -- get the right height and width for scaling DPI */
301 virtual_rect.left = virtual_rect.left * desktophorzres / horzres;
302 virtual_rect.right = virtual_rect.right * desktophorzres / horzres;
303 virtual_rect.top = virtual_rect.top * desktopvertres / vertres;
304 virtual_rect.bottom = virtual_rect.bottom * desktopvertres / vertres;
306 /* desktop -- get the right height and width for scaling DPI */
307 virtual_rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
308 virtual_rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
309 virtual_rect.right = (virtual_rect.left + GetSystemMetrics(SM_CXVIRTUALSCREEN)) * desktophorzres / horzres;
310 virtual_rect.bottom = (virtual_rect.top + GetSystemMetrics(SM_CYVIRTUALSCREEN)) * desktopvertres / vertres;
313 /* If no width or height set, use full screen/window area */
314 if (!gdigrab->width || !gdigrab->height) {
315 clip_rect.left = virtual_rect.left;
316 clip_rect.top = virtual_rect.top;
317 clip_rect.right = virtual_rect.right;
318 clip_rect.bottom = virtual_rect.bottom;
320 clip_rect.left = gdigrab->offset_x;
321 clip_rect.top = gdigrab->offset_y;
322 clip_rect.right = gdigrab->width + gdigrab->offset_x;
323 clip_rect.bottom = gdigrab->height + gdigrab->offset_y;
326 if (clip_rect.left < virtual_rect.left ||
327 clip_rect.top < virtual_rect.top ||
328 clip_rect.right > virtual_rect.right ||
329 clip_rect.bottom > virtual_rect.bottom) {
330 av_log(s1, AV_LOG_ERROR,
331 "Capture area (%li,%li),(%li,%li) extends outside window area (%li,%li),(%li,%li)",
332 clip_rect.left, clip_rect.top,
333 clip_rect.right, clip_rect.bottom,
334 virtual_rect.left, virtual_rect.top,
335 virtual_rect.right, virtual_rect.bottom);
342 av_log(s1, AV_LOG_INFO,
343 "Found window %s, capturing %lix%lix%i at (%li,%li)\n",
345 clip_rect.right - clip_rect.left,
346 clip_rect.bottom - clip_rect.top,
347 bpp, clip_rect.left, clip_rect.top);
349 av_log(s1, AV_LOG_INFO,
350 "Capturing whole desktop as %lix%lix%i at (%li,%li)\n",
351 clip_rect.right - clip_rect.left,
352 clip_rect.bottom - clip_rect.top,
353 bpp, clip_rect.left, clip_rect.top);
356 if (clip_rect.right - clip_rect.left <= 0 ||
357 clip_rect.bottom - clip_rect.top <= 0 || bpp%8) {
358 av_log(s1, AV_LOG_ERROR, "Invalid properties, aborting\n");
363 dest_hdc = CreateCompatibleDC(source_hdc);
365 WIN32_API_ERROR("Screen DC CreateCompatibleDC");
370 /* Create a DIB and select it into the dest_hdc */
371 bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
372 bmi.bmiHeader.biWidth = clip_rect.right - clip_rect.left;
373 bmi.bmiHeader.biHeight = -(clip_rect.bottom - clip_rect.top);
374 bmi.bmiHeader.biPlanes = 1;
375 bmi.bmiHeader.biBitCount = bpp;
376 bmi.bmiHeader.biCompression = BI_RGB;
377 bmi.bmiHeader.biSizeImage = 0;
378 bmi.bmiHeader.biXPelsPerMeter = 0;
379 bmi.bmiHeader.biYPelsPerMeter = 0;
380 bmi.bmiHeader.biClrUsed = 0;
381 bmi.bmiHeader.biClrImportant = 0;
382 hbmp = CreateDIBSection(dest_hdc, &bmi, DIB_RGB_COLORS,
385 WIN32_API_ERROR("Creating DIB Section");
390 if (!SelectObject(dest_hdc, hbmp)) {
391 WIN32_API_ERROR("SelectObject");
396 /* Get info from the bitmap */
397 GetObject(hbmp, sizeof(BITMAP), &bmp);
399 st = avformat_new_stream(s1, NULL);
401 ret = AVERROR(ENOMEM);
404 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
406 gdigrab->frame_size = bmp.bmWidthBytes * bmp.bmHeight * bmp.bmPlanes;
407 gdigrab->header_size = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
408 (bpp <= 8 ? (1 << bpp) : 0) * sizeof(RGBQUAD) /* palette size */;
409 gdigrab->time_base = av_inv_q(gdigrab->framerate);
410 gdigrab->time_frame = av_gettime_relative() / av_q2d(gdigrab->time_base);
412 gdigrab->hwnd = hwnd;
413 gdigrab->source_hdc = source_hdc;
414 gdigrab->dest_hdc = dest_hdc;
415 gdigrab->hbmp = hbmp;
417 gdigrab->buffer = buffer;
418 gdigrab->clip_rect = clip_rect;
420 gdigrab->cursor_error_printed = 0;
422 if (gdigrab->show_region) {
423 if (gdigrab_region_wnd_init(s1, gdigrab)) {
429 st->avg_frame_rate = av_inv_q(gdigrab->time_base);
431 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
432 st->codecpar->codec_id = AV_CODEC_ID_BMP;
433 st->codecpar->bit_rate = (gdigrab->header_size + gdigrab->frame_size) * 1/av_q2d(gdigrab->time_base) * 8;
439 ReleaseDC(hwnd, source_hdc);
445 DeleteDC(source_hdc);
450 * Paints a mouse pointer in a Win32 image.
452 * @param s1 Context of the log information
453 * @param s Current grad structure
455 static void paint_mouse_pointer(AVFormatContext *s1, struct gdigrab *gdigrab)
459 #define CURSOR_ERROR(str) \
460 if (!gdigrab->cursor_error_printed) { \
461 WIN32_API_ERROR(str); \
462 gdigrab->cursor_error_printed = 1; \
465 ci.cbSize = sizeof(ci);
467 if (GetCursorInfo(&ci)) {
468 HCURSOR icon = CopyCursor(ci.hCursor);
471 RECT clip_rect = gdigrab->clip_rect;
472 HWND hwnd = gdigrab->hwnd;
473 int horzres = GetDeviceCaps(gdigrab->source_hdc, HORZRES);
474 int vertres = GetDeviceCaps(gdigrab->source_hdc, VERTRES);
475 int desktophorzres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPHORZRES);
476 int desktopvertres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPVERTRES);
478 info.hbmColor = NULL;
480 if (ci.flags != CURSOR_SHOWING)
484 /* Use the standard arrow cursor as a fallback.
485 * You'll probably only hit this in Wine, which can't fetch
486 * the current system cursor. */
487 icon = CopyCursor(LoadCursor(NULL, IDC_ARROW));
490 if (!GetIconInfo(icon, &info)) {
491 CURSOR_ERROR("Could not get icon info");
498 if (GetWindowRect(hwnd, &rect)) {
499 pos.x = ci.ptScreenPos.x - clip_rect.left - info.xHotspot - rect.left;
500 pos.y = ci.ptScreenPos.y - clip_rect.top - info.yHotspot - rect.top;
502 //that would keep the correct location of mouse with hidpi screens
503 pos.x = pos.x * desktophorzres / horzres;
504 pos.y = pos.y * desktopvertres / vertres;
506 CURSOR_ERROR("Couldn't get window rectangle");
510 //that would keep the correct location of mouse with hidpi screens
511 pos.x = ci.ptScreenPos.x * desktophorzres / horzres - clip_rect.left - info.xHotspot;
512 pos.y = ci.ptScreenPos.y * desktopvertres / vertres - clip_rect.top - info.yHotspot;
515 av_log(s1, AV_LOG_DEBUG, "Cursor pos (%li,%li) -> (%li,%li)\n",
516 ci.ptScreenPos.x, ci.ptScreenPos.y, pos.x, pos.y);
518 if (pos.x >= 0 && pos.x <= clip_rect.right - clip_rect.left &&
519 pos.y >= 0 && pos.y <= clip_rect.bottom - clip_rect.top) {
520 if (!DrawIcon(gdigrab->dest_hdc, pos.x, pos.y, icon))
521 CURSOR_ERROR("Couldn't draw icon");
526 DeleteObject(info.hbmMask);
528 DeleteObject(info.hbmColor);
532 CURSOR_ERROR("Couldn't get cursor info");
537 * Grabs a frame from gdi (public device demuxer API).
539 * @param s1 Context from avformat core
540 * @param pkt Packet holding the grabbed frame
541 * @return frame size in bytes
543 static int gdigrab_read_packet(AVFormatContext *s1, AVPacket *pkt)
545 struct gdigrab *gdigrab = s1->priv_data;
547 HDC dest_hdc = gdigrab->dest_hdc;
548 HDC source_hdc = gdigrab->source_hdc;
549 RECT clip_rect = gdigrab->clip_rect;
550 AVRational time_base = gdigrab->time_base;
551 int64_t time_frame = gdigrab->time_frame;
553 BITMAPFILEHEADER bfh;
554 int file_size = gdigrab->header_size + gdigrab->frame_size;
556 int64_t curtime, delay;
558 /* Calculate the time of the next frame */
559 time_frame += INT64_C(1000000);
561 /* Run Window message processing queue */
562 if (gdigrab->show_region)
563 gdigrab_region_wnd_update(s1, gdigrab);
565 /* wait based on the frame rate */
567 curtime = av_gettime_relative();
568 delay = time_frame * av_q2d(time_base) - curtime;
570 if (delay < INT64_C(-1000000) * av_q2d(time_base)) {
571 time_frame += INT64_C(1000000);
575 if (s1->flags & AVFMT_FLAG_NONBLOCK) {
576 return AVERROR(EAGAIN);
582 if (av_new_packet(pkt, file_size) < 0)
583 return AVERROR(ENOMEM);
584 pkt->pts = av_gettime();
586 /* Blit screen grab */
587 if (!BitBlt(dest_hdc, 0, 0,
588 clip_rect.right - clip_rect.left,
589 clip_rect.bottom - clip_rect.top,
591 clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
592 WIN32_API_ERROR("Failed to capture image");
595 if (gdigrab->draw_mouse)
596 paint_mouse_pointer(s1, gdigrab);
598 /* Copy bits to packet data */
600 bfh.bfType = 0x4d42; /* "BM" in little-endian */
601 bfh.bfSize = file_size;
604 bfh.bfOffBits = gdigrab->header_size;
606 memcpy(pkt->data, &bfh, sizeof(bfh));
608 memcpy(pkt->data + sizeof(bfh), &gdigrab->bmi.bmiHeader, sizeof(gdigrab->bmi.bmiHeader));
610 if (gdigrab->bmi.bmiHeader.biBitCount <= 8)
611 GetDIBColorTable(dest_hdc, 0, 1 << gdigrab->bmi.bmiHeader.biBitCount,
612 (RGBQUAD *) (pkt->data + sizeof(bfh) + sizeof(gdigrab->bmi.bmiHeader)));
614 memcpy(pkt->data + gdigrab->header_size, gdigrab->buffer, gdigrab->frame_size);
616 gdigrab->time_frame = time_frame;
618 return gdigrab->header_size + gdigrab->frame_size;
622 * Closes gdi frame grabber (public device demuxer API).
624 * @param s1 Context from avformat core
625 * @return 0 success, !0 failure
627 static int gdigrab_read_close(AVFormatContext *s1)
629 struct gdigrab *s = s1->priv_data;
632 gdigrab_region_wnd_destroy(s1, s);
635 ReleaseDC(s->hwnd, s->source_hdc);
637 DeleteDC(s->dest_hdc);
639 DeleteObject(s->hbmp);
641 DeleteDC(s->source_hdc);
646 #define OFFSET(x) offsetof(struct gdigrab, x)
647 #define DEC AV_OPT_FLAG_DECODING_PARAM
648 static const AVOption options[] = {
649 { "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
650 { "show_region", "draw border around capture area", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
651 { "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, INT_MAX, DEC },
652 { "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
653 { "offset_x", "capture area x offset", OFFSET(offset_x), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
654 { "offset_y", "capture area y offset", OFFSET(offset_y), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
658 static const AVClass gdigrab_class = {
659 .class_name = "GDIgrab indev",
660 .item_name = av_default_item_name,
662 .version = LIBAVUTIL_VERSION_INT,
663 .category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
666 /** gdi grabber device demuxer declaration */
667 AVInputFormat ff_gdigrab_demuxer = {
669 .long_name = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
670 .priv_data_size = sizeof(struct gdigrab),
671 .read_header = gdigrab_read_header,
672 .read_packet = gdigrab_read_packet,
673 .read_close = gdigrab_read_close,
674 .flags = AVFMT_NOFILE,
675 .priv_class = &gdigrab_class,