我目前的方法是:CGImageRef訪問像素數據的更快方式?
CGDataProviderRef provider = CGImageGetDataProvider(imageRef);
imageData.rawData = CGDataProviderCopyData(provider);
imageData.imageData = (UInt8 *) CFDataGetBytePtr(imageData.rawData);
我只得到約每秒30幀。我知道性能命中的一部分是複製數據,如果我可以訪問字節流並且不會自動爲我創建副本,那將會很好。
我試圖讓它儘快處理CGImageRefs,有沒有更快的方法?
這是我的工作方案片段:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
// Insert code here to initialize your application
//timer = [NSTimer scheduledTimerWithTimeInterval:1.0/60.0 //2000.0
// target:self
// selector:@selector(timerLogic)
// userInfo:nil
// repeats:YES];
leagueGameState = [LeagueGameState new];
[self updateWindowList];
lastTime = CACurrentMediaTime();
// Create a capture session
mSession = [[AVCaptureSession alloc] init];
// Set the session preset as you wish
mSession.sessionPreset = AVCaptureSessionPresetMedium;
// If you're on a multi-display system and you want to capture a secondary display,
// you can call CGGetActiveDisplayList() to get the list of all active displays.
// For this example, we just specify the main display.
// To capture both a main and secondary display at the same time, use two active
// capture sessions, one for each display. On Mac OS X, AVCaptureMovieFileOutput
// only supports writing to a single video track.
CGDirectDisplayID displayId = kCGDirectMainDisplay;
// Create a ScreenInput with the display and add it to the session
AVCaptureScreenInput *input = [[AVCaptureScreenInput alloc] initWithDisplayID:displayId];
input.minFrameDuration = CMTimeMake(1, 60);
//if (!input) {
// [mSession release];
// mSession = nil;
// return;
//}
if ([mSession canAddInput:input]) {
NSLog(@"Added screen capture input");
[mSession addInput:input];
} else {
NSLog(@"Couldn't add screen capture input");
}
//**********************Add output here
//dispatch_queue_t _videoDataOutputQueue;
//_videoDataOutputQueue = dispatch_queue_create("com.apple.sample.capturepipeline.video", DISPATCH_QUEUE_SERIAL);
//dispatch_set_target_queue(_videoDataOutputQueue, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0));
AVCaptureVideoDataOutput *videoOut = [[AVCaptureVideoDataOutput alloc] init];
videoOut.videoSettings = @{ (id)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_32BGRA) };
[videoOut setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
// RosyWriter records videos and we prefer not to have any dropped frames in the video recording.
// By setting alwaysDiscardsLateVideoFrames to NO we ensure that minor fluctuations in system load or in our processing time for a given frame won't cause framedrops.
// We do however need to ensure that on average we can process frames in realtime.
// If we were doing preview only we would probably want to set alwaysDiscardsLateVideoFrames to YES.
videoOut.alwaysDiscardsLateVideoFrames = YES;
if ([mSession canAddOutput:videoOut]) {
NSLog(@"Added output video");
[mSession addOutput:videoOut];
} else {NSLog(@"Couldn't add output video");}
// Start running the session
[mSession startRunning];
NSLog(@"Set up session");
}
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
//NSLog(@"Captures output from sample buffer");
//CMFormatDescriptionRef formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer);
/*
if (self.outputVideoFormatDescription == nil) {
// Don't render the first sample buffer.
// This gives us one frame interval (33ms at 30fps) for setupVideoPipelineWithInputFormatDescription: to complete.
// Ideally this would be done asynchronously to ensure frames don't back up on slower devices.
[self setupVideoPipelineWithInputFormatDescription:formatDescription];
}
else {*/
[self renderVideoSampleBuffer:sampleBuffer];
//}
}
- (void)renderVideoSampleBuffer:(CMSampleBufferRef)sampleBuffer
{
//CVPixelBufferRef renderedPixelBuffer = NULL;
//CMTime timestamp = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
//[self calculateFramerateAtTimestamp:timestamp];
// We must not use the GPU while running in the background.
// setRenderingEnabled: takes the same lock so the caller can guarantee no GPU usage once the setter returns.
//@synchronized(_renderer)
//{
// if (_renderingEnabled) {
CVPixelBufferRef sourcePixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
const int kBytesPerPixel = 4;
CVPixelBufferLockBaseAddress(sourcePixelBuffer, 0);
int bufferWidth = (int)CVPixelBufferGetWidth(sourcePixelBuffer);
int bufferHeight = (int)CVPixelBufferGetHeight(sourcePixelBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(sourcePixelBuffer);
uint8_t *baseAddress = CVPixelBufferGetBaseAddress(sourcePixelBuffer);
int count = 0;
for (int row = 0; row < bufferHeight; row++)
{
uint8_t *pixel = baseAddress + row * bytesPerRow;
for (int column = 0; column < bufferWidth; column++)
{
count ++;
pixel[1] = 0; // De-green (second pixel in BGRA is green)
pixel += kBytesPerPixel;
}
}
CVPixelBufferUnlockBaseAddress(sourcePixelBuffer, 0);
//NSLog(@"Test Looped %d times", count);
CIImage *ciImage = [CIImage imageWithCVImageBuffer:sourcePixelBuffer];
/*
CIContext *temporaryContext = [CIContext contextWithCGContext:
[[NSGraphicsContext currentContext] graphicsPort]
options: nil];
CGImageRef videoImage = [temporaryContext
createCGImage:ciImage
fromRect:CGRectMake(0, 0,
CVPixelBufferGetWidth(sourcePixelBuffer),
CVPixelBufferGetHeight(sourcePixelBuffer))];
*/
//UIImage *uiImage = [UIImage imageWithCGImage:videoImage];
// Create a bitmap rep from the image...
NSBitmapImageRep *bitmapRep = [[NSBitmapImageRep alloc] initWithCIImage:ciImage];
// Create an NSImage and add the bitmap rep to it...
NSImage *image = [[NSImage alloc] init];
[image addRepresentation:bitmapRep];
// Set the output view to the new NSImage.
[imageView setImage:image];
//CGImageRelease(videoImage);
//renderedPixelBuffer = [_renderer copyRenderedPixelBuffer:sourcePixelBuffer];
// }
// else {
// return;
// }
//}
//Profile code? See how fast it's running?
if (CACurrentMediaTime() - lastTime > 3) //10 seconds
{
float time = CACurrentMediaTime() - lastTime;
[fpsText setStringValue:[NSString stringWithFormat:@"Elapsed Time: %f ms, %f fps", time * 1000/loopsTaken, (1000.0)/(time * 1000.0/loopsTaken)]];
lastTime = CACurrentMediaTime();
loopsTaken = 0;
[self updateWindowList];
if (leagueGameState.leaguePID == -1) {
[statusText setStringValue:@"No League Instance Found"];
}
}
else
{
loopsTaken++;
}
}
我甚至通過數據循環後得到每秒的一個非常漂亮的60幀。
它捕獲屏幕,我得到的數據,我修改數據,我重新顯示數據。
我從CGWindowListCreateImage中檢索CGImageRef。這是我的程序正在閱讀的屏幕截圖。我從CGImageRef獲取像素數據以循環播放。 沒有任何實際循環數據的過程讓我下降到30fps。 – Gan
這個通常的工具是AV Foundation,它可以更好地處理它。 https://developer.apple.com/library/mac/qa/qa1740/_index.html –
你是對的!即使在循環顯示像素並修改它們之後,我仍可以使用AV Foundation獲得60 fps! – Gan