Here is some code:
AVCaptureDeviceInput *captureInput = [AVCaptureDeviceInput
deviceInputWithDevice:[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]
error:nil];
/*We setupt the output*/
AVCaptureVideoDataOutput *captureOutput = [[AVCaptureVideoDataOutput alloc] init];
captureOutput.alwaysDiscardsLateVideoFrames = YES;
captureOutput.minFrameDuration = CMTimeMake(1.0, 24.0); //Uncomment it to specify a minimum duration for each video frame
[captureOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
// Set the video output to store frame in BGRA (It is supposed to be faster)
NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
NSDictionary* videoSettings = [NSDictionary dictionaryWithObject:value forKey:key];
[captureOutput setVideoSettings:videoSettings];
/*And we create a capture session*/
self.captureSession = [[AVCaptureSession alloc] init];
self.captureSession.sessionPreset = AVCaptureSessionPresetLow;
/*We add input and output*/
if ([self.captureSession canAddInput:captureInput])
{
[self.captureSessi开发者_开发知识库on addInput:captureInput];
}
if ([self.captureSession canAddOutput:captureOutput])
{
[self.captureSession addOutput:captureOutput];
}
/*We add the preview layer*/
self.prevLayer = [AVCaptureVideoPreviewLayer layerWithSession: self.captureSession];
if ([self.prevLayer isOrientationSupported])
{
[self.prevLayer setOrientation:AVCaptureVideoOrientationLandscapeLeft];
}
self.prevLayer.frame = self.view.bounds;
self.prevLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.view.layer addSublayer: self.prevLayer];
AVCaptureConnection *videoConnection = NULL;
[self.captureSession beginConfiguration];
for ( AVCaptureConnection *connection in [captureOutput connections] )
{
for ( AVCaptureInputPort *port in [connection inputPorts] )
{
if ( [[port mediaType] isEqual:AVMediaTypeVideo] )
{
videoConnection = connection;
}
}
}
if([videoConnection isVideoOrientationSupported]) // **Here it is, its always false**
{
[videoConnection setVideoOrientation:AVCaptureVideoOrientationLandscapeLeft];
}
[self.captureSession commitConfiguration];
[self.captureSession startRunning];
Upd: figured that when exporting video, the AVAssetExportSession loses preferredTransform info.
I ran into the same problem and poked around the AVCamDemo from WWDC. I don't know why (yet) but if you query your videoConnection right after you create all the inputs/outputs/connections then both isVideoOrientationSupported and supportsVideoOrientation return NO.
However, if you query supportsVideoOrientation or isVideoOrientationSupported at some later point (after the GUI is setup for instance) then it will return YES. For instance I query it right after the user clicks the record button just before I call [[self movieFileOutput] startRecordingToOutputFileURL...]
Give it a try, works for me.
From here: http://developer.apple.com/library/ios/#qa/qa1744/_index.html#//apple_ref/doc/uid/DTS40011134
Currently, the capture outputs for a movie file (AVCaptureMovieFileOutput) and still image (AVCaptureStillImageOutput) support setting the orientation, but the data output for processing video frames (AVCaptureVideoDataOutput) does not.
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