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ffmpeg/libavdevice/gdigrab.c

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/*
* GDI video grab interface
*
* This file is part of FFmpeg.
*
* Copyright (C) 2013 Calvin Walton <calvin.walton@kepstin.ca>
* Copyright (C) 2007-2010 Christophe Gisquet <word1.word2@gmail.com>
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* FFmpeg 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* GDI frame device demuxer
* @author Calvin Walton <calvin.walton@kepstin.ca>
* @author Christophe Gisquet <word1.word2@gmail.com>
*/
#include "config.h"
#include "libavformat/internal.h"
#include "libavutil/opt.h"
#include "libavutil/time.h"
#include <windows.h>
/**
* GDI Device Demuxer context
*/
struct gdigrab {
const AVClass *class; /**< Class for private options */
int frame_size; /**< Size in bytes of the frame pixel data */
int header_size; /**< Size in bytes of the DIB header */
AVRational time_base; /**< Time base */
int64_t time_frame; /**< Current time */
int draw_mouse; /**< Draw mouse cursor (private option) */
int show_region; /**< Draw border (private option) */
AVRational framerate; /**< Capture framerate (private option) */
int width; /**< Width of the grab frame (private option) */
int height; /**< Height of the grab frame (private option) */
int offset_x; /**< Capture x offset (private option) */
int offset_y; /**< Capture y offset (private option) */
HWND hwnd; /**< Handle of the window for the grab */
HDC source_hdc; /**< Source device context */
HDC dest_hdc; /**< Destination, source-compatible DC */
BITMAPINFO bmi; /**< Information describing DIB format */
HBITMAP hbmp; /**< Information on the bitmap captured */
void *buffer; /**< The buffer containing the bitmap image data */
RECT clip_rect; /**< The subarea of the screen or window to clip */
HWND region_hwnd; /**< Handle of the region border window */
int cursor_error_printed;
};
#define WIN32_API_ERROR(str) \
av_log(s1, AV_LOG_ERROR, str " (error %li)\n", GetLastError())
#define REGION_WND_BORDER 3
/**
* Callback to handle Windows messages for the region outline window.
*
* In particular, this handles painting the frame rectangle.
*
* @param hwnd The region outline window handle.
* @param msg The Windows message.
* @param wparam First Windows message parameter.
* @param lparam Second Windows message parameter.
* @return 0 success, !0 failure
*/
static LRESULT CALLBACK
gdigrab_region_wnd_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
PAINTSTRUCT ps;
HDC hdc;
RECT rect;
switch (msg) {
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
GetClientRect(hwnd, &rect);
FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
rect.left++; rect.top++; rect.right--; rect.bottom--;
FrameRect(hdc, &rect, GetStockObject(WHITE_BRUSH));
rect.left++; rect.top++; rect.right--; rect.bottom--;
FrameRect(hdc, &rect, GetStockObject(BLACK_BRUSH));
EndPaint(hwnd, &ps);
break;
default:
return DefWindowProc(hwnd, msg, wparam, lparam);
}
return 0;
}
/**
* Initialize the region outline window.
*
* @param s1 The format context.
* @param gdigrab gdigrab context.
* @return 0 success, !0 failure
*/
static int
gdigrab_region_wnd_init(AVFormatContext *s1, struct gdigrab *gdigrab)
{
HWND hwnd;
RECT rect = gdigrab->clip_rect;
HRGN region = NULL;
HRGN region_interior = NULL;
DWORD style = WS_POPUP | WS_VISIBLE;
DWORD ex = WS_EX_TOOLWINDOW | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
rect.left -= REGION_WND_BORDER; rect.top -= REGION_WND_BORDER;
rect.right += REGION_WND_BORDER; rect.bottom += REGION_WND_BORDER;
AdjustWindowRectEx(&rect, style, FALSE, ex);
// Create a window with no owner; use WC_DIALOG instead of writing a custom
// window class
hwnd = CreateWindowEx(ex, WC_DIALOG, NULL, style, rect.left, rect.top,
rect.right - rect.left, rect.bottom - rect.top,
NULL, NULL, NULL, NULL);
if (!hwnd) {
WIN32_API_ERROR("Could not create region display window");
goto error;
}
// Set the window shape to only include the border area
GetClientRect(hwnd, &rect);
region = CreateRectRgn(0, 0,
rect.right - rect.left, rect.bottom - rect.top);
region_interior = CreateRectRgn(REGION_WND_BORDER, REGION_WND_BORDER,
rect.right - rect.left - REGION_WND_BORDER,
rect.bottom - rect.top - REGION_WND_BORDER);
CombineRgn(region, region, region_interior, RGN_DIFF);
if (!SetWindowRgn(hwnd, region, FALSE)) {
WIN32_API_ERROR("Could not set window region");
goto error;
}
// The "region" memory is now owned by the window
region = NULL;
DeleteObject(region_interior);
SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR) gdigrab_region_wnd_proc);
ShowWindow(hwnd, SW_SHOW);
gdigrab->region_hwnd = hwnd;
return 0;
error:
if (region)
DeleteObject(region);
if (region_interior)
DeleteObject(region_interior);
if (hwnd)
DestroyWindow(hwnd);
return 1;
}
/**
* Cleanup/free the region outline window.
*
* @param s1 The format context.
* @param gdigrab gdigrab context.
*/
static void
gdigrab_region_wnd_destroy(AVFormatContext *s1, struct gdigrab *gdigrab)
{
if (gdigrab->region_hwnd)
DestroyWindow(gdigrab->region_hwnd);
gdigrab->region_hwnd = NULL;
}
/**
* Process the Windows message queue.
*
* This is important to prevent Windows from thinking the window has become
* unresponsive. As well, things like WM_PAINT (to actually draw the window
* contents) are handled from the message queue context.
*
* @param s1 The format context.
* @param gdigrab gdigrab context.
*/
static void
gdigrab_region_wnd_update(AVFormatContext *s1, struct gdigrab *gdigrab)
{
HWND hwnd = gdigrab->region_hwnd;
MSG msg;
while (PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE)) {
DispatchMessage(&msg);
}
}
/**
* Initializes the gdi grab device demuxer (public device demuxer API).
*
* @param s1 Context from avformat core
* @return AVERROR_IO error, 0 success
*/
static int
gdigrab_read_header(AVFormatContext *s1)
{
struct gdigrab *gdigrab = s1->priv_data;
HWND hwnd;
HDC source_hdc = NULL;
HDC dest_hdc = NULL;
BITMAPINFO bmi;
HBITMAP hbmp = NULL;
void *buffer = NULL;
const char *filename = s1->url;
const char *name = NULL;
AVStream *st = NULL;
int bpp;
int horzres;
int vertres;
int desktophorzres;
int desktopvertres;
RECT virtual_rect;
RECT clip_rect;
BITMAP bmp;
int ret;
if (!strncmp(filename, "title=", 6)) {
name = filename + 6;
hwnd = FindWindow(NULL, name);
if (!hwnd) {
av_log(s1, AV_LOG_ERROR,
"Can't find window '%s', aborting.\n", name);
ret = AVERROR(EIO);
goto error;
}
if (gdigrab->show_region) {
av_log(s1, AV_LOG_WARNING,
"Can't show region when grabbing a window.\n");
gdigrab->show_region = 0;
}
} else if (!strcmp(filename, "desktop")) {
hwnd = NULL;
} else {
av_log(s1, AV_LOG_ERROR,
"Please use \"desktop\" or \"title=<windowname>\" to specify your target.\n");
ret = AVERROR(EIO);
goto error;
}
/* This will get the device context for the selected window, or if
* none, the primary screen */
source_hdc = GetDC(hwnd);
if (!source_hdc) {
WIN32_API_ERROR("Couldn't get window device context");
ret = AVERROR(EIO);
goto error;
}
bpp = GetDeviceCaps(source_hdc, BITSPIXEL);
horzres = GetDeviceCaps(source_hdc, HORZRES);
vertres = GetDeviceCaps(source_hdc, VERTRES);
desktophorzres = GetDeviceCaps(source_hdc, DESKTOPHORZRES);
desktopvertres = GetDeviceCaps(source_hdc, DESKTOPVERTRES);
if (hwnd) {
GetClientRect(hwnd, &virtual_rect);
/* window -- get the right height and width for scaling DPI */
virtual_rect.left = virtual_rect.left * desktophorzres / horzres;
virtual_rect.right = virtual_rect.right * desktophorzres / horzres;
virtual_rect.top = virtual_rect.top * desktopvertres / vertres;
virtual_rect.bottom = virtual_rect.bottom * desktopvertres / vertres;
} else {
/* desktop -- get the right height and width for scaling DPI */
virtual_rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
virtual_rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
virtual_rect.right = (virtual_rect.left + GetSystemMetrics(SM_CXVIRTUALSCREEN)) * desktophorzres / horzres;
virtual_rect.bottom = (virtual_rect.top + GetSystemMetrics(SM_CYVIRTUALSCREEN)) * desktopvertres / vertres;
}
/* If no width or height set, use full screen/window area */
if (!gdigrab->width || !gdigrab->height) {
clip_rect.left = virtual_rect.left;
clip_rect.top = virtual_rect.top;
clip_rect.right = virtual_rect.right;
clip_rect.bottom = virtual_rect.bottom;
} else {
clip_rect.left = gdigrab->offset_x;
clip_rect.top = gdigrab->offset_y;
clip_rect.right = gdigrab->width + gdigrab->offset_x;
clip_rect.bottom = gdigrab->height + gdigrab->offset_y;
}
if (clip_rect.left < virtual_rect.left ||
clip_rect.top < virtual_rect.top ||
clip_rect.right > virtual_rect.right ||
clip_rect.bottom > virtual_rect.bottom) {
av_log(s1, AV_LOG_ERROR,
"Capture area (%li,%li),(%li,%li) extends outside window area (%li,%li),(%li,%li)",
clip_rect.left, clip_rect.top,
clip_rect.right, clip_rect.bottom,
virtual_rect.left, virtual_rect.top,
virtual_rect.right, virtual_rect.bottom);
ret = AVERROR(EIO);
goto error;
}
if (name) {
av_log(s1, AV_LOG_INFO,
"Found window %s, capturing %lix%lix%i at (%li,%li)\n",
name,
clip_rect.right - clip_rect.left,
clip_rect.bottom - clip_rect.top,
bpp, clip_rect.left, clip_rect.top);
} else {
av_log(s1, AV_LOG_INFO,
"Capturing whole desktop as %lix%lix%i at (%li,%li)\n",
clip_rect.right - clip_rect.left,
clip_rect.bottom - clip_rect.top,
bpp, clip_rect.left, clip_rect.top);
}
if (clip_rect.right - clip_rect.left <= 0 ||
clip_rect.bottom - clip_rect.top <= 0 || bpp%8) {
av_log(s1, AV_LOG_ERROR, "Invalid properties, aborting\n");
ret = AVERROR(EIO);
goto error;
}
dest_hdc = CreateCompatibleDC(source_hdc);
if (!dest_hdc) {
WIN32_API_ERROR("Screen DC CreateCompatibleDC");
ret = AVERROR(EIO);
goto error;
}
/* Create a DIB and select it into the dest_hdc */
bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth = clip_rect.right - clip_rect.left;
bmi.bmiHeader.biHeight = -(clip_rect.bottom - clip_rect.top);
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = bpp;
bmi.bmiHeader.biCompression = BI_RGB;
bmi.bmiHeader.biSizeImage = 0;
bmi.bmiHeader.biXPelsPerMeter = 0;
bmi.bmiHeader.biYPelsPerMeter = 0;
bmi.bmiHeader.biClrUsed = 0;
bmi.bmiHeader.biClrImportant = 0;
hbmp = CreateDIBSection(dest_hdc, &bmi, DIB_RGB_COLORS,
&buffer, NULL, 0);
if (!hbmp) {
WIN32_API_ERROR("Creating DIB Section");
ret = AVERROR(EIO);
goto error;
}
if (!SelectObject(dest_hdc, hbmp)) {
WIN32_API_ERROR("SelectObject");
ret = AVERROR(EIO);
goto error;
}
/* Get info from the bitmap */
GetObject(hbmp, sizeof(BITMAP), &bmp);
st = avformat_new_stream(s1, NULL);
if (!st) {
ret = AVERROR(ENOMEM);
goto error;
}
avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
gdigrab->frame_size = bmp.bmWidthBytes * bmp.bmHeight * bmp.bmPlanes;
gdigrab->header_size = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
(bpp <= 8 ? (1 << bpp) : 0) * sizeof(RGBQUAD) /* palette size */;
gdigrab->time_base = av_inv_q(gdigrab->framerate);
gdigrab->time_frame = av_gettime_relative() / av_q2d(gdigrab->time_base);
gdigrab->hwnd = hwnd;
gdigrab->source_hdc = source_hdc;
gdigrab->dest_hdc = dest_hdc;
gdigrab->hbmp = hbmp;
gdigrab->bmi = bmi;
gdigrab->buffer = buffer;
gdigrab->clip_rect = clip_rect;
gdigrab->cursor_error_printed = 0;
if (gdigrab->show_region) {
if (gdigrab_region_wnd_init(s1, gdigrab)) {
ret = AVERROR(EIO);
goto error;
}
}
st->avg_frame_rate = av_inv_q(gdigrab->time_base);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_BMP;
st->codecpar->bit_rate = (gdigrab->header_size + gdigrab->frame_size) * 1/av_q2d(gdigrab->time_base) * 8;
return 0;
error:
if (source_hdc)
ReleaseDC(hwnd, source_hdc);
if (dest_hdc)
DeleteDC(dest_hdc);
if (hbmp)
DeleteObject(hbmp);
if (source_hdc)
DeleteDC(source_hdc);
return ret;
}
/**
* Paints a mouse pointer in a Win32 image.
*
* @param s1 Context of the log information
* @param s Current grad structure
*/
static void paint_mouse_pointer(AVFormatContext *s1, struct gdigrab *gdigrab)
{
CURSORINFO ci = {0};
#define CURSOR_ERROR(str) \
if (!gdigrab->cursor_error_printed) { \
WIN32_API_ERROR(str); \
gdigrab->cursor_error_printed = 1; \
}
ci.cbSize = sizeof(ci);
if (GetCursorInfo(&ci)) {
HCURSOR icon = CopyCursor(ci.hCursor);
ICONINFO info;
POINT pos;
RECT clip_rect = gdigrab->clip_rect;
HWND hwnd = gdigrab->hwnd;
int horzres = GetDeviceCaps(gdigrab->source_hdc, HORZRES);
int vertres = GetDeviceCaps(gdigrab->source_hdc, VERTRES);
int desktophorzres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPHORZRES);
int desktopvertres = GetDeviceCaps(gdigrab->source_hdc, DESKTOPVERTRES);
info.hbmMask = NULL;
info.hbmColor = NULL;
if (ci.flags != CURSOR_SHOWING)
return;
if (!icon) {
/* Use the standard arrow cursor as a fallback.
* You'll probably only hit this in Wine, which can't fetch
* the current system cursor. */
icon = CopyCursor(LoadCursor(NULL, IDC_ARROW));
}
if (!GetIconInfo(icon, &info)) {
CURSOR_ERROR("Could not get icon info");
goto icon_error;
}
if (hwnd) {
RECT rect;
if (GetWindowRect(hwnd, &rect)) {
pos.x = ci.ptScreenPos.x - clip_rect.left - info.xHotspot - rect.left;
pos.y = ci.ptScreenPos.y - clip_rect.top - info.yHotspot - rect.top;
//that would keep the correct location of mouse with hidpi screens
pos.x = pos.x * desktophorzres / horzres;
pos.y = pos.y * desktopvertres / vertres;
} else {
CURSOR_ERROR("Couldn't get window rectangle");
goto icon_error;
}
} else {
//that would keep the correct location of mouse with hidpi screens
pos.x = ci.ptScreenPos.x * desktophorzres / horzres - clip_rect.left - info.xHotspot;
pos.y = ci.ptScreenPos.y * desktopvertres / vertres - clip_rect.top - info.yHotspot;
}
av_log(s1, AV_LOG_DEBUG, "Cursor pos (%li,%li) -> (%li,%li)\n",
ci.ptScreenPos.x, ci.ptScreenPos.y, pos.x, pos.y);
if (pos.x >= 0 && pos.x <= clip_rect.right - clip_rect.left &&
pos.y >= 0 && pos.y <= clip_rect.bottom - clip_rect.top) {
if (!DrawIcon(gdigrab->dest_hdc, pos.x, pos.y, icon))
CURSOR_ERROR("Couldn't draw icon");
}
icon_error:
if (info.hbmMask)
DeleteObject(info.hbmMask);
if (info.hbmColor)
DeleteObject(info.hbmColor);
if (icon)
DestroyCursor(icon);
} else {
CURSOR_ERROR("Couldn't get cursor info");
}
}
/**
* Grabs a frame from gdi (public device demuxer API).
*
* @param s1 Context from avformat core
* @param pkt Packet holding the grabbed frame
* @return frame size in bytes
*/
static int gdigrab_read_packet(AVFormatContext *s1, AVPacket *pkt)
{
struct gdigrab *gdigrab = s1->priv_data;
HDC dest_hdc = gdigrab->dest_hdc;
HDC source_hdc = gdigrab->source_hdc;
RECT clip_rect = gdigrab->clip_rect;
AVRational time_base = gdigrab->time_base;
int64_t time_frame = gdigrab->time_frame;
BITMAPFILEHEADER bfh;
int file_size = gdigrab->header_size + gdigrab->frame_size;
int64_t curtime, delay;
/* Calculate the time of the next frame */
time_frame += INT64_C(1000000);
/* Run Window message processing queue */
if (gdigrab->show_region)
gdigrab_region_wnd_update(s1, gdigrab);
/* wait based on the frame rate */
for (;;) {
curtime = av_gettime_relative();
delay = time_frame * av_q2d(time_base) - curtime;
if (delay <= 0) {
if (delay < INT64_C(-1000000) * av_q2d(time_base)) {
time_frame += INT64_C(1000000);
}
break;
}
if (s1->flags & AVFMT_FLAG_NONBLOCK) {
return AVERROR(EAGAIN);
} else {
av_usleep(delay);
}
}
if (av_new_packet(pkt, file_size) < 0)
return AVERROR(ENOMEM);
pkt->pts = av_gettime();
/* Blit screen grab */
if (!BitBlt(dest_hdc, 0, 0,
clip_rect.right - clip_rect.left,
clip_rect.bottom - clip_rect.top,
source_hdc,
clip_rect.left, clip_rect.top, SRCCOPY | CAPTUREBLT)) {
WIN32_API_ERROR("Failed to capture image");
return AVERROR(EIO);
}
if (gdigrab->draw_mouse)
paint_mouse_pointer(s1, gdigrab);
/* Copy bits to packet data */
bfh.bfType = 0x4d42; /* "BM" in little-endian */
bfh.bfSize = file_size;
bfh.bfReserved1 = 0;
bfh.bfReserved2 = 0;
bfh.bfOffBits = gdigrab->header_size;
memcpy(pkt->data, &bfh, sizeof(bfh));
memcpy(pkt->data + sizeof(bfh), &gdigrab->bmi.bmiHeader, sizeof(gdigrab->bmi.bmiHeader));
if (gdigrab->bmi.bmiHeader.biBitCount <= 8)
GetDIBColorTable(dest_hdc, 0, 1 << gdigrab->bmi.bmiHeader.biBitCount,
(RGBQUAD *) (pkt->data + sizeof(bfh) + sizeof(gdigrab->bmi.bmiHeader)));
memcpy(pkt->data + gdigrab->header_size, gdigrab->buffer, gdigrab->frame_size);
gdigrab->time_frame = time_frame;
return gdigrab->header_size + gdigrab->frame_size;
}
/**
* Closes gdi frame grabber (public device demuxer API).
*
* @param s1 Context from avformat core
* @return 0 success, !0 failure
*/
static int gdigrab_read_close(AVFormatContext *s1)
{
struct gdigrab *s = s1->priv_data;
if (s->show_region)
gdigrab_region_wnd_destroy(s1, s);
if (s->source_hdc)
ReleaseDC(s->hwnd, s->source_hdc);
if (s->dest_hdc)
DeleteDC(s->dest_hdc);
if (s->hbmp)
DeleteObject(s->hbmp);
if (s->source_hdc)
DeleteDC(s->source_hdc);
return 0;
}
#define OFFSET(x) offsetof(struct gdigrab, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "draw_mouse", "draw the mouse pointer", OFFSET(draw_mouse), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, DEC },
{ "show_region", "draw border around capture area", OFFSET(show_region), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
{ "framerate", "set video frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "ntsc"}, 0, INT_MAX, DEC },
{ "video_size", "set video frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
{ "offset_x", "capture area x offset", OFFSET(offset_x), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
{ "offset_y", "capture area y offset", OFFSET(offset_y), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, DEC },
{ NULL },
};
static const AVClass gdigrab_class = {
.class_name = "GDIgrab indev",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
.category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
};
/** gdi grabber device demuxer declaration */
AVInputFormat ff_gdigrab_demuxer = {
.name = "gdigrab",
.long_name = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
.priv_data_size = sizeof(struct gdigrab),
.read_header = gdigrab_read_header,
.read_packet = gdigrab_read_packet,
.read_close = gdigrab_read_close,
.flags = AVFMT_NOFILE,
.priv_class = &gdigrab_class,
};
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