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ffmpeg/libavdevice/x11grab.c

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/*
* X11 video grab interface
*
* This file is part of Libav.
*
* Libav integration:
* Copyright (C) 2006 Clemens Fruhwirth <clemens@endorphin.org>
* Edouard Gomez <ed.gomez@free.fr>
*
* This file contains code from grab.c:
* Copyright (c) 2000-2001 Fabrice Bellard
*
* This file contains code from the xvidcap project:
* Copyright (C) 1997-1998 Rasca, Berlin
* 2003-2004 Karl H. Beckers, Frankfurt
*
* Libav is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Libav 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* X11 frame device demuxer
* @author Clemens Fruhwirth <clemens@endorphin.org>
* @author Edouard Gomez <ed.gomez@free.fr>
*/
#include "config.h"
#include <time.h>
#include <sys/shm.h>
#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/Xlibint.h>
#include <X11/Xproto.h>
#include <X11/Xutil.h>
#include <X11/extensions/shape.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/XShm.h>
#include "libavutil/internal.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/time.h"
#include "libavformat/avformat.h"
#include "libavformat/internal.h"
/** X11 device demuxer context */
typedef struct X11GrabContext {
const AVClass *class; /**< Class for private options. */
int frame_size; /**< Size in bytes of a grabbed frame */
AVRational time_base; /**< Time base */
int64_t time_frame; /**< Current time */
char *video_size; /**< String describing video size, set by a private option. */
int height; /**< Height of the grab frame */
int width; /**< Width of the grab frame */
int x_off; /**< Horizontal top-left corner coordinate */
int y_off; /**< Vertical top-left corner coordinate */
Display *dpy; /**< X11 display from which x11grab grabs frames */
XImage *image; /**< X11 image holding the grab */
int use_shm; /**< !0 when using XShm extension */
XShmSegmentInfo shminfo; /**< When using XShm, keeps track of XShm info */
int draw_mouse; /**< Set by a private option. */
int follow_mouse; /**< Set by a private option. */
int show_region; /**< set by a private option. */
char *framerate; /**< Set by a private option. */
Window region_win; /**< This is used by show_region option. */
} X11GrabContext;
#define REGION_WIN_BORDER 3
/**
* Draw grabbing region window
*
* @param s x11grab context
*/
static void x11grab_draw_region_win(X11GrabContext *s)
{
Display *dpy = s->dpy;
Window win = s->region_win;
int screen = DefaultScreen(dpy);
GC gc = XCreateGC(dpy, win, 0, 0);
XSetForeground(dpy, gc, WhitePixel(dpy, screen));
XSetBackground(dpy, gc, BlackPixel(dpy, screen));
XSetLineAttributes(dpy, gc, REGION_WIN_BORDER, LineDoubleDash, 0, 0);
XDrawRectangle(dpy, win, gc, 1, 1,
(s->width + REGION_WIN_BORDER * 2) - 1 * 2 - 1,
(s->height + REGION_WIN_BORDER * 2) - 1 * 2 - 1);
XFreeGC(dpy, gc);
}
/**
* Initialize grabbing region window
*
* @param s x11grab context
*/
static void x11grab_region_win_init(X11GrabContext *s)
{
Display *dpy = s->dpy;
XRectangle rect;
XSetWindowAttributes attribs = { .override_redirect = True };
int screen = DefaultScreen(dpy);
s->region_win = XCreateWindow(dpy, RootWindow(dpy, screen),
s->x_off - REGION_WIN_BORDER,
s->y_off - REGION_WIN_BORDER,
s->width + REGION_WIN_BORDER * 2,
s->height + REGION_WIN_BORDER * 2,
0, CopyFromParent,
InputOutput, CopyFromParent,
CWOverrideRedirect, &attribs);
rect.x = 0;
rect.y = 0;
rect.width = s->width;
rect.height = s->height;
XShapeCombineRectangles(dpy, s->region_win,
ShapeBounding, REGION_WIN_BORDER, REGION_WIN_BORDER,
&rect, 1, ShapeSubtract, 0);
XMapWindow(dpy, s->region_win);
XSelectInput(dpy, s->region_win, ExposureMask | StructureNotifyMask);
x11grab_draw_region_win(s);
}
static int setup_shm(AVFormatContext *s, Display *dpy, XImage **image)
{
X11GrabContext *g = s->priv_data;
int scr = XDefaultScreen(dpy);
XImage *img = XShmCreateImage(dpy, DefaultVisual(dpy, scr),
DefaultDepth(dpy, scr), ZPixmap, NULL,
&g->shminfo, g->width, g->height);
g->shminfo.shmid = shmget(IPC_PRIVATE, img->bytes_per_line * img->height,
IPC_CREAT | 0777);
if (g->shminfo.shmid == -1) {
av_log(s, AV_LOG_ERROR, "Cannot get shared memory!\n");
return AVERROR(ENOMEM);
}
g->shminfo.shmaddr = img->data = shmat(g->shminfo.shmid, 0, 0);
g->shminfo.readOnly = False;
if (!XShmAttach(dpy, &g->shminfo)) {
av_log(s, AV_LOG_ERROR, "Failed to attach shared memory!\n");
/* needs some better error subroutine :) */
return AVERROR(EIO);
}
*image = img;
return 0;
}
static int setup_mouse(Display *dpy, int screen)
{
int ev_ret, ev_err;
if (XFixesQueryExtension(dpy, &ev_ret, &ev_err)) {
Window root = RootWindow(dpy, screen);
XFixesSelectCursorInput(dpy, root, XFixesDisplayCursorNotifyMask);
return 0;
}
return AVERROR(ENOSYS);
}
static int pixfmt_from_image(AVFormatContext *s, XImage *image, int *pix_fmt)
{
av_log(s, AV_LOG_DEBUG,
"Image r 0x%.6lx g 0x%.6lx b 0x%.6lx and depth %i\n",
image->red_mask,
image->green_mask,
image->blue_mask,
image->bits_per_pixel);
switch (image->bits_per_pixel) {
case 8:
*pix_fmt = AV_PIX_FMT_PAL8;
break;
case 16:
if (image->red_mask == 0xf800 &&
image->green_mask == 0x07e0 &&
image->blue_mask == 0x001f) {
*pix_fmt = AV_PIX_FMT_RGB565;
} else if (image->red_mask == 0x7c00 &&
image->green_mask == 0x03e0 &&
image->blue_mask == 0x001f) {
*pix_fmt = AV_PIX_FMT_RGB555;
}
break;
case 24:
if (image->red_mask == 0xff0000 &&
image->green_mask == 0x00ff00 &&
image->blue_mask == 0x0000ff) {
*pix_fmt = AV_PIX_FMT_BGR24;
} else if (image->red_mask == 0x0000ff &&
image->green_mask == 0x00ff00 &&
image->blue_mask == 0xff0000) {
*pix_fmt = AV_PIX_FMT_RGB24;
}
break;
case 32:
*pix_fmt = AV_PIX_FMT_RGB32;
break;
default:
av_log(s, AV_LOG_ERROR,
"XImages with RGB mask 0x%.6lx 0x%.6lx 0x%.6lx and depth %i "
"are currently not supported.\n",
image->red_mask,
image->green_mask,
image->blue_mask,
image->bits_per_pixel);
return AVERROR_PATCHWELCOME;
}
return 0;
}
/**
* Initialize the x11 grab device demuxer (public device demuxer API).
*
* @param s1 Context from avformat core
* @return <ul>
* <li>AVERROR(ENOMEM) no memory left</li>
* <li>AVERROR(EIO) other failure case</li>
* <li>0 success</li>
* </ul>
*/
static int x11grab_read_header(AVFormatContext *s1)
{
X11GrabContext *x11grab = s1->priv_data;
Display *dpy;
AVStream *st = NULL;
XImage *image;
int x_off = 0, y_off = 0, ret = 0, screen, use_shm;
char *param, *offset;
AVRational framerate;
param = av_strdup(s1->filename);
if (!param)
goto out;
offset = strchr(param, '+');
if (offset) {
sscanf(offset, "%d,%d", &x_off, &y_off);
x11grab->draw_mouse = !strstr(offset, "nomouse");
*offset = 0;
}
ret = av_parse_video_size(&x11grab->width, &x11grab->height,
x11grab->video_size);
if (ret < 0) {
av_log(s1, AV_LOG_ERROR, "Couldn't parse video size.\n");
goto out;
}
ret = av_parse_video_rate(&framerate, x11grab->framerate);
if (ret < 0) {
av_log(s1, AV_LOG_ERROR, "Could not parse framerate: %s.\n",
x11grab->framerate);
goto out;
}
av_log(s1, AV_LOG_INFO,
"device: %s -> display: %s x: %d y: %d width: %d height: %d\n",
s1->filename, param, x_off, y_off, x11grab->width, x11grab->height);
dpy = XOpenDisplay(param);
if (!dpy) {
av_log(s1, AV_LOG_ERROR, "Could not open X display.\n");
ret = AVERROR(EIO);
goto out;
}
st = avformat_new_stream(s1, NULL);
if (!st) {
ret = AVERROR(ENOMEM);
goto out;
}
avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
screen = DefaultScreen(dpy);
if (x11grab->follow_mouse) {
int screen_w, screen_h;
Window w;
screen_w = DisplayWidth(dpy, screen);
screen_h = DisplayHeight(dpy, screen);
XQueryPointer(dpy, RootWindow(dpy, screen), &w, &w, &x_off, &y_off,
&ret, &ret, &ret);
x_off -= x11grab->width / 2;
y_off -= x11grab->height / 2;
x_off = FFMIN(FFMAX(x_off, 0), screen_w - x11grab->width);
y_off = FFMIN(FFMAX(y_off, 0), screen_h - x11grab->height);
av_log(s1, AV_LOG_INFO,
"followmouse is enabled, resetting grabbing region to x: %d y: %d\n",
x_off, y_off);
}
use_shm = XShmQueryExtension(dpy);
av_log(s1, AV_LOG_INFO,
"shared memory extension %sfound\n", use_shm ? "" : "not ");
if (use_shm && setup_shm(s1, dpy, &image) < 0) {
av_log(s1, AV_LOG_WARNING, "Falling back to XGetImage\n");
use_shm = 0;
}
if (!use_shm) {
image = XGetImage(dpy, RootWindow(dpy, screen),
x_off, y_off,
x11grab->width, x11grab->height,
AllPlanes, ZPixmap);
}
if (x11grab->draw_mouse && setup_mouse(dpy, screen) < 0) {
av_log(s1, AV_LOG_WARNING,
"XFixes not available, cannot draw the mouse cursor\n");
x11grab->draw_mouse = 0;
}
x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel / 8;
x11grab->dpy = dpy;
x11grab->time_base = (AVRational) { framerate.den, framerate.num };
x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
x11grab->x_off = x_off;
x11grab->y_off = y_off;
x11grab->image = image;
x11grab->use_shm = use_shm;
ret = pixfmt_from_image(s1, image, &st->codecpar->format);
if (ret < 0)
goto out;
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
st->codecpar->width = x11grab->width;
st->codecpar->height = x11grab->height;
st->codecpar->bit_rate = x11grab->frame_size * 1 / av_q2d(x11grab->time_base) * 8;
st->avg_frame_rate = av_inv_q(x11grab->time_base);
out:
av_free(param);
return ret;
}
/**
* Paint a mouse pointer in an X11 image.
*
* @param image image to paint the mouse pointer to
* @param s context used to retrieve original grabbing rectangle
* coordinates
*/
static void paint_mouse_pointer(XImage *image, X11GrabContext *s)
{
int x_off = s->x_off;
int y_off = s->y_off;
int width = s->width;
int height = s->height;
Display *dpy = s->dpy;
XFixesCursorImage *xcim;
int x, y;
int line, column;
int to_line, to_column;
int pixstride = image->bits_per_pixel >> 3;
/* Warning: in its insanity, xlib provides unsigned image data through a
* char* pointer, so we have to make it uint8_t to make things not break.
* Anyone who performs further investigation of the xlib API likely risks
* permanent brain damage. */
uint8_t *pix = image->data;
/* Code doesn't currently support 16-bit or PAL8 */
if (image->bits_per_pixel != 24 && image->bits_per_pixel != 32)
return;
xcim = XFixesGetCursorImage(dpy);
if (!xcim)
return;
x = xcim->x - xcim->xhot;
y = xcim->y - xcim->yhot;
to_line = FFMIN((y + xcim->height), (height + y_off));
to_column = FFMIN((x + xcim->width), (width + x_off));
for (line = FFMAX(y, y_off); line < to_line; line++) {
for (column = FFMAX(x, x_off); column < to_column; column++) {
int xcim_addr = (line - y) * xcim->width + column - x;
int image_addr = ((line - y_off) * width + column - x_off) * pixstride;
int r = (uint8_t)(xcim->pixels[xcim_addr] >> 0);
int g = (uint8_t)(xcim->pixels[xcim_addr] >> 8);
int b = (uint8_t)(xcim->pixels[xcim_addr] >> 16);
int a = (uint8_t)(xcim->pixels[xcim_addr] >> 24);
if (a == 255) {
pix[image_addr + 0] = r;
pix[image_addr + 1] = g;
pix[image_addr + 2] = b;
} else if (a) {
/* pixel values from XFixesGetCursorImage come premultiplied by alpha */
pix[image_addr + 0] = r + (pix[image_addr + 0] * (255 - a) + 255 / 2) / 255;
pix[image_addr + 1] = g + (pix[image_addr + 1] * (255 - a) + 255 / 2) / 255;
pix[image_addr + 2] = b + (pix[image_addr + 2] * (255 - a) + 255 / 2) / 255;
}
}
}
XFree(xcim);
xcim = NULL;
}
/**
* Read new data in the image structure.
*
* @param dpy X11 display to grab from
* @param d
* @param image Image where the grab will be put
* @param x Top-Left grabbing rectangle horizontal coordinate
* @param y Top-Left grabbing rectangle vertical coordinate
* @return 0 if error, !0 if successful
*/
static int xget_zpixmap(Display *dpy, Drawable d, XImage *image, int x, int y)
{
xGetImageReply rep;
xGetImageReq *req;
long nbytes;
if (!image)
return 0;
LockDisplay(dpy);
GetReq(GetImage, req);
/* First set up the standard stuff in the request */
req->drawable = d;
req->x = x;
req->y = y;
req->width = image->width;
req->height = image->height;
req->planeMask = (unsigned int)AllPlanes;
req->format = ZPixmap;
if (!_XReply(dpy, (xReply *)&rep, 0, xFalse) || !rep.length) {
UnlockDisplay(dpy);
SyncHandle();
return 0;
}
nbytes = (long)rep.length << 2;
_XReadPad(dpy, image->data, nbytes);
UnlockDisplay(dpy);
SyncHandle();
return 1;
}
/**
* Grab a frame from x11 (public device demuxer API).
*
* @param s1 Context from avformat core
* @param pkt Packet holding the brabbed frame
* @return frame size in bytes
*/
static int x11grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
{
X11GrabContext *s = s1->priv_data;
Display *dpy = s->dpy;
XImage *image = s->image;
int x_off = s->x_off;
int y_off = s->y_off;
int follow_mouse = s->follow_mouse;
int screen, pointer_x, pointer_y, _, same_screen = 1;
Window w, root;
int64_t curtime, delay;
struct timespec ts;
/* Calculate the time of the next frame */
s->time_frame += INT64_C(1000000);
/* wait based on the frame rate */
for (;;) {
curtime = av_gettime();
delay = s->time_frame * av_q2d(s->time_base) - curtime;
if (delay <= 0) {
if (delay < INT64_C(-1000000) * av_q2d(s->time_base))
s->time_frame += INT64_C(1000000);
break;
}
ts.tv_sec = delay / 1000000;
ts.tv_nsec = (delay % 1000000) * 1000;
nanosleep(&ts, NULL);
}
pkt->data = image->data;
pkt->size = s->frame_size;
pkt->pts = curtime;
screen = DefaultScreen(dpy);
root = RootWindow(dpy, screen);
if (follow_mouse || s->draw_mouse)
same_screen = XQueryPointer(dpy, root, &w, &w,
&pointer_x, &pointer_y, &_, &_, &_);
if (follow_mouse && same_screen) {
int screen_w, screen_h;
screen_w = DisplayWidth(dpy, screen);
screen_h = DisplayHeight(dpy, screen);
if (follow_mouse == -1) {
// follow the mouse, put it at center of grabbing region
x_off += pointer_x - s->width / 2 - x_off;
y_off += pointer_y - s->height / 2 - y_off;
} else {
// follow the mouse, but only move the grabbing region when mouse
// reaches within certain pixels to the edge.
if (pointer_x > x_off + s->width - follow_mouse)
x_off += pointer_x - (x_off + s->width - follow_mouse);
else if (pointer_x < x_off + follow_mouse)
x_off -= (x_off + follow_mouse) - pointer_x;
if (pointer_y > y_off + s->height - follow_mouse)
y_off += pointer_y - (y_off + s->height - follow_mouse);
else if (pointer_y < y_off + follow_mouse)
y_off -= (y_off + follow_mouse) - pointer_y;
}
// adjust grabbing region position if it goes out of screen.
s->x_off = x_off = FFMIN(FFMAX(x_off, 0), screen_w - s->width);
s->y_off = y_off = FFMIN(FFMAX(y_off, 0), screen_h - s->height);
if (s->show_region && s->region_win)
XMoveWindow(dpy, s->region_win,
s->x_off - REGION_WIN_BORDER,
s->y_off - REGION_WIN_BORDER);
}
if (s->show_region && same_screen) {
if (s->region_win) {
XEvent evt = { .type = NoEventMask };
// Clean up the events, and do the initial draw or redraw.
while (XCheckMaskEvent(dpy, ExposureMask | StructureNotifyMask,
&evt))
;
if (evt.type)
x11grab_draw_region_win(s);
} else {
x11grab_region_win_init(s);
}
}
if (s->use_shm) {
if (!XShmGetImage(dpy, root, image, x_off, y_off, AllPlanes))
av_log(s1, AV_LOG_INFO, "XShmGetImage() failed\n");
} else {
if (!xget_zpixmap(dpy, root, image, x_off, y_off))
av_log(s1, AV_LOG_INFO, "XGetZPixmap() failed\n");
}
if (s->draw_mouse && same_screen)
paint_mouse_pointer(image, s);
return s->frame_size;
}
/**
* Close x11 frame grabber (public device demuxer API).
*
* @param s1 Context from avformat core
* @return 0 success, !0 failure
*/
static int x11grab_read_close(AVFormatContext *s1)
{
X11GrabContext *x11grab = s1->priv_data;
/* Detach cleanly from shared mem */
if (x11grab->use_shm) {
XShmDetach(x11grab->dpy, &x11grab->shminfo);
shmdt(x11grab->shminfo.shmaddr);
shmctl(x11grab->shminfo.shmid, IPC_RMID, NULL);
}
/* Destroy X11 image */
if (x11grab->image) {
XDestroyImage(x11grab->image);
x11grab->image = NULL;
}
if (x11grab->region_win)
XDestroyWindow(x11grab->dpy, x11grab->region_win);
/* Free X11 display */
XCloseDisplay(x11grab->dpy);
return 0;
}
#define OFFSET(x) offsetof(X11GrabContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "grab_x", "Initial x coordinate.", OFFSET(x_off), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
{ "grab_y", "Initial y coordinate.", OFFSET(y_off), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, DEC },
{ "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), AV_OPT_TYPE_STRING, {.str = "vga"}, 0, 0, DEC },
{ "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc"}, 0, 0, DEC },
{ "draw_mouse", "Draw the mouse pointer.", OFFSET(draw_mouse), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, DEC },
{ "follow_mouse", "Move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region.",
OFFSET(follow_mouse), AV_OPT_TYPE_INT, { .i64 = 0 }, -1, INT_MAX, DEC, "follow_mouse" },
{ "centered", "Keep the mouse pointer at the center of grabbing region when following.", 0, AV_OPT_TYPE_CONST, { .i64 = -1 }, INT_MIN, INT_MAX, DEC, "follow_mouse" },
{ "show_region", "Show the grabbing region.", OFFSET(show_region), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, DEC },
{ NULL },
};
static const AVClass x11_class = {
.class_name = "X11grab indev",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
/** x11 grabber device demuxer declaration */
AVInputFormat ff_x11grab_demuxer = {
.name = "x11grab",
.long_name = NULL_IF_CONFIG_SMALL("X11grab"),
.priv_data_size = sizeof(X11GrabContext),
.read_header = x11grab_read_header,
.read_packet = x11grab_read_packet,
.read_close = x11grab_read_close,
.flags = AVFMT_NOFILE,
.priv_class = &x11_class,
};
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