On Sat, 6 Feb 2021, Paul B Mahol wrote:
What happens if you use non-existing window?
I added an error message for this case, but the output video is still created
(empty). Is there a value I can return to avoid this?
On Sun, 7 Feb 2021, Andriy Gelman wrote:
Also the commit title should start with avdevice/xcbgrab: or lavd/xcbgrab:
done
If you try with -show_region 1, the border gets drawn in the wrong place.
fixed
I also fixed the misalignement of draw_mouse I didn't notice last time.
+@item window_id
+Grab this window, instead of the whole screen.
+
I think it would be useful to say how to get a window id.
Probably worth adding what happens if the window size changes or it
disappears.
Done. Recording also ends when the window is iconified or reduced in size beyond
the video size.
For now I disabled follow_mouse and select_region when window_id is given.
xcb_window_t is uint32_t, so max should be UINT32_MAX?
Indeed.
@@ -825,6 +827,9 @@ static av_cold int xcbgrab_read_header(AVFormatContext
*s)
return AVERROR(EIO);
}
+ if (c->window_id == 0)
+ c->window_id = c->screen->root;
+
Can 0 be a valid window_id? Maybe it's better to use -1 for default. I saw the
function xcb_generate_id() returns -1 on error.
0 is not a valid x11 identifier, but it's better to use the XCB_NONE macro for
it (in Xlib and higher-level libraries, it's "None")
Thanks!
Thanks,
--
Andriy
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From e13c1be7abd6989b3ad80fd8086fe6a0819fd810 Mon Sep 17 00:00:00 2001
From: sgerwk <sge...@aol.com>
Date: Wed, 10 Feb 2021 17:36:00 +0100
Subject: [PATCH] libavdevice/xcbgrab: option for grabbing a window instead of
desktop
---
doc/indevs.texi | 14 +++++++-
libavdevice/xcbgrab.c | 79 ++++++++++++++++++++++++++++++++-----------
2 files changed, 72 insertions(+), 21 deletions(-)
diff --git a/doc/indevs.texi b/doc/indevs.texi
index 3924d03..48fd2b1 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -1564,8 +1564,20 @@ With @var{follow_mouse}:
ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25
-video_size cif -i :0.0 out.mpg
@end example
+@item window_id
+Grab this window, instead of the whole screen.
+
+The id of a window can be found by xwininfo(1), possibly with options -tree and
+-root.
+
+If the window is later enlarged, the new area is not recorded. Video ends when
+the window is closed, unmapped (i.e., iconified) or shrunk beyond the video
+size (which defaults to the initial window size).
+
+This option disables options @option{follow_mouse} and @option{select_region}.
+
@item video_size
-Set the video frame size. Default is the full desktop.
+Set the video frame size. Default is the full desktop or window.
@item grab_x
@item grab_y
diff --git a/libavdevice/xcbgrab.c b/libavdevice/xcbgrab.c
index be5d5ea..7697090 100644
--- a/libavdevice/xcbgrab.c
+++ b/libavdevice/xcbgrab.c
@@ -60,6 +60,8 @@ typedef struct XCBGrabContext {
AVRational time_base;
int64_t frame_duration;
+ xcb_window_t window_id;
+ int win_x, win_y;
int x, y;
int width, height;
int frame_size;
@@ -82,6 +84,7 @@ typedef struct XCBGrabContext {
#define OFFSET(x) offsetof(XCBGrabContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
+ { "window_id", "Window to capture", OFFSET(window_id), AV_OPT_TYPE_INT, {
.i64 = XCB_NONE }, 0, UINT32_MAX, D },
{ "x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 = 0 },
0, INT_MAX, D },
{ "y", "Initial y coordinate.", OFFSET(y), AV_OPT_TYPE_INT, { .i64 = 0 },
0, INT_MAX, D },
{ "grab_x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 =
0 }, 0, INT_MAX, D },
@@ -157,7 +160,7 @@ static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
XCBGrabContext *c = s->priv_data;
xcb_get_image_cookie_t iq;
xcb_get_image_reply_t *img;
- xcb_drawable_t drawable = c->screen->root;
+ xcb_drawable_t drawable = c->window_id;
xcb_generic_error_t *e = NULL;
uint8_t *data;
int length;
@@ -267,7 +270,7 @@ static int xcbgrab_frame_shm(AVFormatContext *s, AVPacket
*pkt)
XCBGrabContext *c = s->priv_data;
xcb_shm_get_image_cookie_t iq;
xcb_shm_get_image_reply_t *img;
- xcb_drawable_t drawable = c->screen->root;
+ xcb_drawable_t drawable = c->window_id;
xcb_generic_error_t *e = NULL;
AVBufferRef *buf;
xcb_shm_seg_t segment;
@@ -355,17 +358,17 @@ static void xcbgrab_draw_mouse(AVFormatContext *s,
AVPacket *pkt,
cx = ci->x - ci->xhot;
cy = ci->y - ci->yhot;
- x = FFMAX(cx, gr->x);
- y = FFMAX(cy, gr->y);
+ x = FFMAX(cx, gr->win_x + gr->x);
+ y = FFMAX(cy, gr->win_y + gr->y);
- w = FFMIN(cx + ci->width, gr->x + gr->width) - x;
- h = FFMIN(cy + ci->height, gr->y + gr->height) - y;
+ w = FFMIN(cx + ci->width, gr->win_x + gr->x + gr->width) - x;
+ h = FFMIN(cy + ci->height, gr->win_y + gr->y + gr->height) - y;
c_off = x - cx;
- i_off = x - gr->x;
+ i_off = x - gr->x - gr->win_x;
cursor += (y - cy) * ci->width;
- image += (y - gr->y) * gr->width * stride;
+ image += (y - gr->y - gr->win_y) * gr->width * stride;
for (y = 0; y < h; y++) {
cursor += c_off;
@@ -403,8 +406,8 @@ static void xcbgrab_draw_mouse(AVFormatContext *s, AVPacket
*pkt,
static void xcbgrab_update_region(AVFormatContext *s)
{
XCBGrabContext *c = s->priv_data;
- const uint32_t args[] = { c->x - c->region_border,
- c->y - c->region_border };
+ const uint32_t args[] = { c->win_x + c->x - c->region_border,
+ c->win_y + c->y - c->region_border };
xcb_configure_window(c->conn,
c->window,
@@ -417,16 +420,22 @@ static int xcbgrab_read_packet(AVFormatContext *s,
AVPacket *pkt)
XCBGrabContext *c = s->priv_data;
xcb_query_pointer_cookie_t pc;
xcb_get_geometry_cookie_t gc;
+ xcb_translate_coordinates_cookie_t tc;
xcb_query_pointer_reply_t *p = NULL;
xcb_get_geometry_reply_t *geo = NULL;
+ xcb_translate_coordinates_reply_t *translate = NULL;
int ret = 0;
int64_t pts;
pts = wait_frame(s, pkt);
- if (c->follow_mouse || c->draw_mouse) {
- pc = xcb_query_pointer(c->conn, c->screen->root);
- gc = xcb_get_geometry(c->conn, c->screen->root);
+ if (c->window_id == c->screen->root) {
+ c->win_x = 0;
+ c->win_y = 0;
+ }
+ if (c->follow_mouse || c->draw_mouse || c->window_id != c->screen->root) {
+ pc = xcb_query_pointer(c->conn, c->window_id);
+ gc = xcb_get_geometry(c->conn, c->window_id);
p = xcb_query_pointer_reply(c->conn, pc, NULL);
if (!p) {
av_log(s, AV_LOG_ERROR, "Failed to query xcb pointer\n");
@@ -438,6 +447,12 @@ static int xcbgrab_read_packet(AVFormatContext *s,
AVPacket *pkt)
free(p);
return AVERROR_EXTERNAL;
}
+ tc = xcb_translate_coordinates(c->conn, c->window_id, c->screen->root,
geo->x, geo->y);
+ translate = xcb_translate_coordinates_reply(c->conn, tc, NULL);
+ if (!translate)
+ return AVERROR_EXTERNAL;
+ c->win_x = translate->dst_x;
+ c->win_y = translate->dst_y;
}
if (c->follow_mouse && p->same_screen)
@@ -447,7 +462,7 @@ static int xcbgrab_read_packet(AVFormatContext *s, AVPacket
*pkt)
xcbgrab_update_region(s);
#if CONFIG_LIBXCB_SHM
- if (c->has_shm && xcbgrab_frame_shm(s, pkt) < 0) {
+ if (c->has_shm && (ret = xcbgrab_frame_shm(s, pkt)) == AVERROR(ENOMEM)) {
av_log(s, AV_LOG_WARNING, "Continuing without shared memory.\n");
c->has_shm = 0;
}
@@ -558,7 +573,9 @@ static int create_stream(AVFormatContext *s)
XCBGrabContext *c = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
xcb_get_geometry_cookie_t gc;
+ xcb_translate_coordinates_cookie_t tc;
xcb_get_geometry_reply_t *geo;
+ xcb_translate_coordinates_reply_t *translate;
int64_t frame_size_bits;
int ret;
@@ -571,11 +588,20 @@ static int create_stream(AVFormatContext *s)
avpriv_set_pts_info(st, 64, 1, 1000000);
- gc = xcb_get_geometry(c->conn, c->screen->root);
+ gc = xcb_get_geometry(c->conn, c->window_id);
geo = xcb_get_geometry_reply(c->conn, gc, NULL);
- if (!geo)
+ if (!geo) {
+ av_log(s, AV_LOG_ERROR, "Can't find window '0x%x', aborting.\n",
c->window_id);
+ return AVERROR_EXTERNAL;
+ }
+
+ tc = xcb_translate_coordinates(c->conn, c->window_id, c->screen->root,
geo->x, geo->y);
+ translate = xcb_translate_coordinates_reply(c->conn, tc, NULL);
+ if (!translate)
return AVERROR_EXTERNAL;
+ c->win_x = translate->dst_x;
+ c->win_y = translate->dst_y;
if (!c->width || !c->height) {
c->width = geo->width;
c->height = geo->height;
@@ -750,7 +776,7 @@ static int select_region(AVFormatContext *s)
press_position = (xcb_point_t){ press->event_x, press->event_y };
rectangle.x = press_position.x;
rectangle.y = press_position.y;
- xcb_poly_rectangle(conn, root_window, gc, 1, &rectangle);
+ xcb_poly_rectangle(conn, c->window_id, gc, 1, &rectangle);
was_pressed = 1;
break;
}
@@ -759,14 +785,14 @@ static int select_region(AVFormatContext *s)
xcb_motion_notify_event_t *motion =
(xcb_motion_notify_event_t *)event;
xcb_point_t cursor_position = { motion->event_x,
motion->event_y };
- xcb_poly_rectangle(conn, root_window, gc, 1, &rectangle);
+ xcb_poly_rectangle(conn, c->window_id, gc, 1, &rectangle);
rectangle = rectangle_from_corners(&press_position,
&cursor_position);
- xcb_poly_rectangle(conn, root_window, gc, 1, &rectangle);
+ xcb_poly_rectangle(conn, c->window_id, gc, 1, &rectangle);
}
break;
}
case XCB_BUTTON_RELEASE: {
- xcb_poly_rectangle(conn, root_window, gc, 1, &rectangle);
+ xcb_poly_rectangle(conn, c->window_id, gc, 1, &rectangle);
done = 1;
break;
}
@@ -830,6 +856,19 @@ static av_cold int xcbgrab_read_header(AVFormatContext *s)
return AVERROR(EIO);
}
+ if (c->window_id == XCB_NONE)
+ c->window_id = c->screen->root;
+ else {
+ if (c->select_region) {
+ av_log(s, AV_LOG_WARNING, "select_region ignored with
window_id.\n");
+ c->select_region = 0;
+ }
+ if (c->follow_mouse) {
+ av_log(s, AV_LOG_WARNING, "follow_mouse ignored with
window_id.\n");
+ c->follow_mouse = 0;
+ }
+ }
+
if (c->select_region) {
ret = select_region(s);
if (ret < 0) {
--
2.30.0
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