更改摄像头和设备方向

Question

我有一个基本上是视图的应用程序，当用户单击按钮时，摄像头可视化开始。

我想允许当相机不能显示所有方向，但是当相机表现，我需要强制应用到肖像模式，因为如果它不是肖像，视频旋转。当相机关闭时，应用程序可能会再次旋转。

你知道，如果我能解决视频定位的问题？

或者我该如何强制应用程序进入肖像模式？我知道在早期的ios版本中，您可以使用[UIDevice setOrientation:]，但它已被最近的ios所弃用。

我怎样才能为iOS 5和iOS 6做到这一点？

我已经试过：

[self presentViewController:[UIViewController new] animated:NO 
completion:^{ [self dismissViewControllerAnimated:NO completion:nil]; }]; 

而且在shouldAutorotateToInterfaceOrientation方法：

if (state == CAMERA) { 
     return (interfaceOrientation == UIInterfaceOrientationPortrait); 
    }else{ 
     return YES; 
} 

它工作正常，并迫使应用肖像。但是当相机关闭时，它不能正常工作，它不能很好地旋转。

我的意思是，当相机被关闭，这是发生了什么：

• 应用程序是在人像
• 如果我尝试旋转应用程序，设备旋转而不是应用程序。我可以看到有关时间，电池等信息的ipad状态栏被旋转，但该应用程序没有。
• 如果我再次去肖像，然后旋转设备，它工作正常。

你知道可能是什么问题呢？

在此先感谢。

Answer 1

我想我找到了在同一时间与变化相机和设备方向的问题的解决方案。

我把这个代码时，我初始化摄像头，并且还shouldAutorotateToInterfaceOrientation方法，在这里我允许所有的方位。

AVCaptureVideoOrientation newOrientation; 

    UIInterfaceOrientation deviceOrientation = [UIApplication sharedApplication].statusBarOrientation; 

    NSLog(@"deviceOrientation %c",deviceOrientation); 

    switch (deviceOrientation) 
    { 
     case UIInterfaceOrientationPortrait: 
      NSLog(@"UIInterfaceOrientationPortrait"); 
      newOrientation = AVCaptureVideoOrientationPortrait; 
      break; 
     case UIInterfaceOrientationLandscapeRight: 
      NSLog(@"UIInterfaceOrientationLandscapeRight"); 
      newOrientation = AVCaptureVideoOrientationLandscapeRight; 
      break; 
     case UIInterfaceOrientationLandscapeLeft: 
      NSLog(@"UIInterfaceOrientationLandscapeLeft"); 
      newOrientation = AVCaptureVideoOrientationLandscapeLeft; 
      break; 
     default: 
      NSLog(@"default"); 
      newOrientation = AVCaptureVideoOrientationPortrait; 
      break; 
    } 

    if ([self.prevLayer respondsToSelector:@selector(connection)]){ 
     if ([self.prevLayer.connection isVideoOrientationSupported]){ 
      self.prevLayer.connection.videoOrientation = newOrientation; 
     }else{ 
      NSLog(@"NO respond to selector connection"); 
     } 
    }else{ 


if ([self.prevLayer isOrientationSupported]){ 
     self.prevLayer.orientation = newOrientation; 
    }else{ 
     NSLog(@"NO isOrientationSupported"); 
    } 

} 

Answer 2

请尝试以下为方向代码，所以我认为你的问题可以得到解决。

- (void)encodeVideoOrientation:(NSURL *)anOutputFileURL 
    { 
    CGAffineTransform rotationTransform; 
    CGAffineTransform rotateTranslate; 
    CGSize renderSize; 

    switch (self.recordingOrientation) 
    { 
     // set these 3 values based on orientation 

    } 


    AVURLAsset * videoAsset = [[AVURLAsset alloc]initWithURL:anOutputFileURL options:nil]; 

    AVAssetTrack *sourceVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]; 
    AVAssetTrack *sourceAudioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; 

    AVMutableComposition* composition = [AVMutableComposition composition]; 

    AVMutableCompositionTrack *compositionVideoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid]; 
    [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) 
            ofTrack:sourceVideoTrack 
            atTime:kCMTimeZero error:nil]; 
    [compositionVideoTrack setPreferredTransform:sourceVideoTrack.preferredTransform]; 

    AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio 
                       preferredTrackID:kCMPersistentTrackID_Invalid]; 
    [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) 
            ofTrack:sourceAudioTrack 
            atTime:kCMTimeZero error:nil]; 



    AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction]; 
    AVMutableVideoCompositionLayerInstruction *layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:compositionVideoTrack]; 
    [layerInstruction setTransform:rotateTranslate atTime:kCMTimeZero]; 

    AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition]; 
    videoComposition.frameDuration = CMTimeMake(1,30); 
    videoComposition.renderScale = 1.0; 
    videoComposition.renderSize = renderSize; 
    instruction.layerInstructions = [NSArray arrayWithObject: layerInstruction]; 
    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration); 
    videoComposition.instructions = [NSArray arrayWithObject: instruction]; 

    AVAssetExportSession * assetExport = [[AVAssetExportSession alloc] initWithAsset:composition 
                      presetName:AVAssetExportPresetMediumQuality]; 

    NSString* videoName = @"export.mov"; 
    NSString *exportPath = [NSTemporaryDirectory() stringByAppendingPathComponent:videoName]; 

    NSURL * exportUrl = [NSURL fileURLWithPath:exportPath]; 

    if ([[NSFileManager defaultManager] fileExistsAtPath:exportPath]) 
    { 
     [[NSFileManager defaultManager] removeItemAtPath:exportPath error:nil]; 
    } 

    assetExport.outputFileType = AVFileTypeMPEG4; 
    assetExport.outputURL = exportUrl; 
    assetExport.shouldOptimizeForNetworkUse = YES; 
    assetExport.videoComposition = videoComposition; 

    [assetExport exportAsynchronouslyWithCompletionHandler: 
    ^(void) { 
     switch (assetExport.status) 
     { 
      case AVAssetExportSessionStatusCompleted: 
       //    export complete 
       NSLog(@"Export Complete"); 
       break; 
      case AVAssetExportSessionStatusFailed: 
       NSLog(@"Export Failed"); 
       NSLog(@"ExportSessionError: %@", [assetExport.error localizedDescription]); 
       //    export error (see exportSession.error) 
       break; 
      case AVAssetExportSessionStatusCancelled: 
       NSLog(@"Export Failed"); 
       NSLog(@"ExportSessionError: %@", [assetExport.error localizedDescription]); 
       //    export cancelled 
       break; 
     } 
    }]; 

    } 

希望这可以帮助你。