We are having issues with ScreenCaptureKit. Our use case is the following:
We have multiple applications that each starts a stream capture, using ScreenCaptureKit. It works fine when just one application is streaming, but when starting multiple streams continuesly, all streams stops or crashes, without ScreenCaptureKit reporting an error back.
Restarting replayd for the user will allow us to start streaming again, if the streaming applications are restartet too.
We have build a small test program that we have tested on different Macs, running different versions of macOS, with identical results. The test program just calls the 'getShareableContentExcludingDesktopWindows' function multiple times, since this was the simplest way to show the problem.
Our test setup is the following:
Mac Mini M2 macOS 13.6
MacBook Pro M3 macOS 14.4
MacBook Pro M3 macOS 15.1
Code main.m
#import <Foundation/Foundation.h>
#import <ScreenCaptureKit/ScreenCaptureKit.h>
@interface Runner : NSObject
@property(atomic, assign) BOOL keepRunning;
@property(atomic, retain) SCShareableContent* availableWindows;
-(void) updateAvailableWindows;
-(void) notif:(NSNotification*) aNotif;
@end
int main(int argc, const char * argv[]) {
@autoreleasepool {
NSRunLoop* loo = [NSRunLoop mainRunLoop];
Runner* r = [[Runner alloc] init];
[r updateAvailableWindows];
while (r.keepRunning)
[loo runUntilDate:[NSDate distantFuture]];
NSLog(@"Program exit");
}
return 0;
}
@implementation Runner
-(instancetype) init
{
self = [super init];
if(self){
_keepRunning = YES;
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notif:) name:@"windowWasNotFound" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notif:) name:@"windowWasFound" object:nil];
}
return self;
}
-(void) updateAvailableWindows
{
@autoreleasepool {
NSLog(@"begin");
[SCShareableContent getShareableContentExcludingDesktopWindows:NO onScreenWindowsOnly:YES completionHandler:^(SCShareableContent* content, NSError* error){
NSLog(@"running");
if(!error){
self.availableWindows = content;
for (__unused SCWindow* aWin in self.availableWindows.windows) {
[NSThread sleepForTimeInterval:0.01];
}
[[NSNotificationCenter defaultCenter] postNotificationName:@"windowWasFound" object:self.availableWindows];
}
else{
[[NSNotificationCenter defaultCenter] postNotificationName:@"windowWasNotFound" object:nil];
}
}];
}
}
-(void) notif:(NSNotification*) aNotif
{
if(aNotif.object)
[self performSelectorOnMainThread:@selector(updateAvailableWindows) withObject:nil waitUntilDone:NO];
else{
NSLog(@"Not Found");
self.keepRunning = NO;
}
}
@end
How to replicate:
Compile and run the program from multiple terminal windows (terminal must be granted screen recording permission) and notice that the output stops, when the replayd stops responding (our assumption). Restarting the application does nothing, before the replayd also is restarted.
Running th application in Xcode gives the following error:
[ERROR] -[RPDaemonProxy fetchShareableContentWithOption:windowID:currentProcess:withCompletionHandler:]_block_invoke:902 error: 4097
This error is not something we have been able to detect in our applications - and since the only workaround is restarting replayd and the applications, catching the error would help us.
