Hello friends. Please pardon this short reprise, but I really need help - maybe
someone can shed some light on my problem.
I’m capturing video using AVFoundation APIs for preview only (OS-X app)
following an old sample-code from Apple (AVRecorder). My view hierarchy is
simple. An NSView (WantsLayer=YES) with a AVCaptureVideoPreviewLayer as
sublayer. This worked for several years now.
Recently I added modest CoreImage CIFilter (CISharpenLuminance) to the video
preview like so:
1. I call setLayerUsesCoreImageFilters:YES on the NSView hosting the video
capture.
2. I programmatically create and apply the filter to the
AVCaptureVideoPreviewLayer.
From that moment on - I see strange warnings in the console: "Fallingback to
pbuffer. FBO status is 36054” for every captured video frame (30 a sec…).
In other mailing list, someone claims the problem only happens with OS-X.11,
and only with YUV pixel formats. He found the problem in another Apple sample
code -AVGreenScreenPlayer.
Unfortunately the video devices I use only provide YUV pixel formats, and my
client Macs only run OS-X 10.11.
Can someone tell me what is the source of this error line? what is FBO, and
what has fallen-back? where is a documentation of the error, and is there a
workaround the problem?
Any hint will be greatly appreciated. Here’s my code with the new additions
marked with // <— new code
// Get our videoView and its CALayer, to draw video and other stuff on it.
CALayer *videoViewLayer = [[delegate videoView] layer]; // here the
delegate is an NSWindowController.
NSRect bounds = [videoViewLayer bounds];
[[delegate videoView] setLayerUsesCoreImageFilters:YES];
// <— new code
// Create and Add videoCapture layer to our videoView.
AVCaptureVideoPreviewLayer *videoPreviewLayer = [[AVCaptureVideoPreviewLayer
alloc] initWithSession:[self session]];
[videoPreviewLayer
setBackgroundColor:CGColorGetConstantColor(kCGColorClear)];
[videoPreviewLayer setVideoGravity:AVLayerVideoGravityResize];
[videoPreviewLayer setFrame:bounds];
[videoPreviewLayer setAutoresizingMask:kCALayerWidthSizable |
kCALayerHeightSizable];
CIFilter *sharpenLuminance = [CIFilter
filterWithName:@"CISharpenLuminance"]; // <— new code
[sharpenLuminance setValue:@0.5 forKey:kCIInputSharpnessKey];
// <—new code
[videoPreviewLayer setFilters:@[sharpenLuminance]];
// <— new code
[videoViewLayer addSublayer:videoPreviewLayer];
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