AVCaptureSession指定捕获图像的分辨率和质量obj-c iPhone应用程序

您应更改的参数为captureSession.sessionPreset Hi I want to setup AV capture session to capture images with specific resolution (and, if possible, with specific quality) using iphone camera. here's setupping AV session code// Create and configure a capture session and start it running- (void)setupCaptureSession{ NSError *error = nil; // Create the session self.captureSession = [[AVCaptureSession alloc] init]; // Configure the session to produce lower resolution video frames, if your // processing algorithm can cope. We'll specify medium quality for the // chosen device. captureSession.sessionPreset = AVCaptureSessionPresetMedium; // Find a suitable AVCaptureDevice NSArray *cameras=[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; AVCaptureDevice *device; if ([UserDefaults camera]==UIImagePickerControllerCameraDeviceFront) { device =[cameras objectAtIndex:1]; } else { device = [cameras objectAtIndex:0]; }; // Create a device input with the device and add it to the session. AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error]; if (!input) { NSLog(@"PANIC: no media input"); } [captureSession addInput:input]; // Create a VideoDataOutput and add it to the session AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init]; [captureSession addOutput:output]; NSLog(@"connections: %@", output.connections); // Configure your output. dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL); [output setSampleBufferDelegate:self queue:queue]; dispatch_release(queue); // Specify the pixel format output.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey]; // If you wish to cap the frame rate to a known value, such as 15 fps, set // minFrameDuration. // Assign session to an ivar. [self setSession:captureSession]; [self.captureSession startRunning];}and setSession:-(void)setSession:(AVCaptureSession *)session{ NSLog(@"setting session..."); self.captureSession=session; NSLog(@"setting camera view"); self.previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session]; //UIView *aView = self.view; CGRect videoRect = CGRectMake(20.0, 20.0, 280.0, 255.0); previewLayer.frame = videoRect; // Assume you want the preview layer to fill the view. [previewLayer setBackgroundColor:[[UIColor grayColor] CGColor]]; [self.view.layer addSublayer:previewLayer]; //[aView.layer addSublayer:previewLayer];}and output methods:// Delegate routine that is called when a sample buffer was written- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{ //NSLog(@"captureOutput: didOutputSampleBufferFromConnection"); // Create a UIImage from the sample buffer data self.currentImage = [self imageFromSampleBuffer:sampleBuffer]; //< Add your code here that uses the image >}// Create a UIImage from sample buffer data- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer{ //NSLog(@"imageFromSampleBuffer: called"); // Get a CMSampleBuffer's Core Video image buffer for the media data CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); // Lock the base address of the pixel buffer CVPixelBufferLockBaseAddress(imageBuffer, 0); // Get the number of bytes per row for the pixel buffer void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); // Get the number of bytes per row for the pixel buffer size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); // Get the pixel buffer width and height size_t width = CVPixelBufferGetWidth(imageBuffer); size_t height = CVPixelBufferGetHeight(imageBuffer); // Create a device-dependent RGB color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // Create a bitmap graphics context with the sample buffer data CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); // Create a Quartz image from the pixel data in the bitmap graphics context CGImageRef quartzImage = CGBitmapContextCreateImage(context); // Unlock the pixel buffer CVPixelBufferUnlockBaseAddress(imageBuffer,0); // Free up the context and color space CGContextRelease(context); CGColorSpaceRelease(colorSpace); // Create an image object from the Quartz image UIImage *image = [UIImage imageWithCGImage:quartzImage]; // Release the Quartz image CGImageRelease(quartzImage); return (image);}Everything is quite standard. But where and what should I change to specify the resolution of captured image and it's quality. Help me please 解决方案 Refer to Apple's guide Capturing Still Images section regarding which sizes you'll get if you set one or another preset.The parameter you should change is captureSession.sessionPreset 这篇关于AVCaptureSession指定捕获图像的分辨率和质量obj-c iPhone应用程序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！