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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-07 11:13:41 +02:00
FFmpeg/libavdevice/gdigrab.c
Andreas Rheinhardt 790f793844 avutil/common: Don't auto-include mem.h
There are lots of files that don't need it: The number of object
files that actually need it went down from 2011 to 884 here.

Keep it for external users in order to not cause breakages.

Also improve the other headers a bit while just at it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-31 00:08:43 +01:00

692 lines
22 KiB
C

/*
* 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/demux.h"
#include "libavformat/internal.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/time.h"
#include "libavutil/wchar_filename.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)) {
wchar_t *name_w = NULL;
name = filename + 6;
if(utf8towchar(name, &name_w)) {
ret = AVERROR(errno);
goto error;
}
if(!name_w) {
ret = AVERROR(EINVAL);
goto error;
}
hwnd = FindWindowW(NULL, name_w);
av_freep(&name_w);
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 if (!strncmp(filename, "hwnd=", 5)) {
char *p;
name = filename + 5;
hwnd = (HWND) strtoull(name, &p, 0);
if (p == NULL || p == name || p[0] == '\0')
{
av_log(s1, AV_LOG_ERROR,
"Invalid window handle '%s', must be a valid integer.\n", name);
ret = AVERROR(EINVAL);
goto error;
}
} else {
av_log(s1, AV_LOG_ERROR,
"Please use \"desktop\", \"title=<windowname>\" or \"hwnd=<hwnd>\" 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 */
const FFInputFormat ff_gdigrab_demuxer = {
.p.name = "gdigrab",
.p.long_name = NULL_IF_CONFIG_SMALL("GDI API Windows frame grabber"),
.p.flags = AVFMT_NOFILE,
.p.priv_class = &gdigrab_class,
.priv_data_size = sizeof(struct gdigrab),
.read_header = gdigrab_read_header,
.read_packet = gdigrab_read_packet,
.read_close = gdigrab_read_close,
};