Allow use of CroppingWindowCapturer via CreateWindowCapturer
Currently, apps using WebRTC for window capture only get the benefits of
using CroppingWindowCapturer on Windows (described below) after changing
calls to DesktopCapturer::CreateWindowCapturer to instead call
CroppingWindowCapturer::CreateCapturer. This change adds a new flag to
DesktopCaptureOptions to allow opting in to the faster capture-screen-
and-crop path via the older & more discoverable API.
Benefits of using CroppingWindowCapturer's capture-screen-and-crop path
when possible:
1) It's significantly faster, up to ~36ms/frame (~160x) faster than the
capture-window-contents path in my testing (more details are in the
bug). This difference increased with the recent fix for
https://crbug.com/webrtc/10734 .
2) It allows capture of menus & tooltips (plus dialogs if
https://crbug.com/webrtc/10767 is fixed), partially mitigating
https://crbug.com/980864 .
Downsides of using it:
1) It may inadvertently capture occluding windows that aren't detected
properly, e.g. some system UI: https://crbug.com/webrtc/10835 .
2) It may capture some neighboring regions when moving/resizing the
captured window.
The new flag is not enabled by default, so the default behavior is
unchanged. This could perhaps be revisited after addressing
https://crbug.com/webrtc/10835 .
Bug: webrtc:10825
Change-Id: Ib77e5facc7240c5df311fe1fe204d0d8ea22a96a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/146823
Commit-Queue: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#28695}
diff --git a/modules/desktop_capture/desktop_capture_options.h b/modules/desktop_capture/desktop_capture_options.h
index 9473547..11e5f4c 100644
--- a/modules/desktop_capture/desktop_capture_options.h
+++ b/modules/desktop_capture/desktop_capture_options.h
@@ -112,6 +112,22 @@
void set_allow_directx_capturer(bool enabled) {
allow_directx_capturer_ = enabled;
}
+
+ // Flag that may be set to allow use of the cropping window capturer (which
+ // captures the screen & crops that to the window region in some cases). An
+ // advantage of using this is significantly higher capture frame rates than
+ // capturing the window directly. A disadvantage of using this is the
+ // possibility of capturing unrelated content (e.g. overlapping windows that
+ // aren't detected properly, or neighboring regions when moving/resizing the
+ // captured window). Note: this flag influences the behavior of calls to
+ // DesktopCapturer::CreateWindowCapturer; calls to
+ // CroppingWindowCapturer::CreateCapturer ignore the flag (treat it as true).
+ bool allow_cropping_window_capturer() const {
+ return allow_cropping_window_capturer_;
+ }
+ void set_allow_cropping_window_capturer(bool allow) {
+ allow_cropping_window_capturer_ = allow;
+ }
#endif
#if defined(WEBRTC_USE_PIPEWIRE)
@@ -134,6 +150,7 @@
#if defined(WEBRTC_WIN)
bool allow_use_magnification_api_ = false;
bool allow_directx_capturer_ = false;
+ bool allow_cropping_window_capturer_ = false;
#endif
#if defined(USE_X11)
bool use_update_notifications_ = false;
diff --git a/modules/desktop_capture/desktop_capturer.cc b/modules/desktop_capture/desktop_capturer.cc
index b636611..df625e9 100644
--- a/modules/desktop_capture/desktop_capturer.cc
+++ b/modules/desktop_capture/desktop_capturer.cc
@@ -16,6 +16,7 @@
#include <cstring>
#include <utility>
+#include "modules/desktop_capture/cropping_window_capturer.h"
#include "modules/desktop_capture/desktop_capture_options.h"
#include "modules/desktop_capture/desktop_capturer_differ_wrapper.h"
@@ -47,6 +48,12 @@
// static
std::unique_ptr<DesktopCapturer> DesktopCapturer::CreateWindowCapturer(
const DesktopCaptureOptions& options) {
+#if defined(WEBRTC_WIN)
+ if (options.allow_cropping_window_capturer()) {
+ return CroppingWindowCapturer::CreateCapturer(options);
+ }
+#endif // defined(WEBRTC_WIN)
+
std::unique_ptr<DesktopCapturer> capturer = CreateRawWindowCapturer(options);
if (capturer && options.detect_updated_region()) {
capturer.reset(new DesktopCapturerDifferWrapper(std::move(capturer)));
