我正在开发一个应用程序，用户可以在其中放大和缩小视频。我正在使用 AV Foundation 录制视频，但是当用户录制视频时，我无法放大和缩小视频。
我正在使用以下代码录制视频
- (void) startCamera
NSLog(@"Setting up capture session");
CaptureSession = [[AVCaptureSession alloc] init];
//----- ADD INPUTS -----
NSLog(@"Adding video input");
//ADD VIDEO INPUT
AVCaptureDevice *VideoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (VideoDevice)
{
NSError *error;
VideoInputDevice = [AVCaptureDeviceInput deviceInputWithDevice:VideoDevice error:&error];
if (!error)
{
if ([CaptureSession canAddInput:VideoInputDevice])
[CaptureSession addInput:VideoInputDevice];
else
NSLog(@"Couldn't add video input");
}
else
{
NSLog(@"Couldn't create video input");
}
}
else
{
NSLog(@"Couldn't create video capture device");
}
//ADD AUDIO INPUT
NSLog(@"Adding audio input");
AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
NSError *error = nil;
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevice error:&error];
if (audioInput)
{
[CaptureSession addInput:audioInput];
}
//----- ADD OUTPUTS -----
//ADD VIDEO PREVIEW LAYER
NSLog(@"Adding video preview layer");
[self setPreviewLayer:[[AVCaptureVideoPreviewLayer alloc] initWithSession:CaptureSession]];
PreviewLayer.orientation = AVCaptureVideoOrientationPortrait; //<<SET ORIENTATION. You can deliberatly set this wrong to flip the image and may actually need to set it wrong to get the right image
[[self PreviewLayer] setVideoGravity:AVLayerVideoGravityResizeAspectFill];
//ADD MOVIE FILE OUTPUT
NSLog(@"Adding movie file output");
MovieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
Float64 TotalSeconds = 60; //Total seconds
int32_t preferredTimeScale = 30; //Frames per second
CMTime maxDuration = CMTimeMakeWithSeconds(TotalSeconds, preferredTimeScale); //<<SET MAX DURATION
MovieFileOutput.maxRecordedDuration = maxDuration;
MovieFileOutput.minFreeDiskSpaceLimit = 1024 * 1024; //<<SET MIN FREE SPACE IN BYTES FOR RECORDING TO CONTINUE ON A VOLUME
if ([CaptureSession canAddOutput:MovieFileOutput])
[CaptureSession addOutput:MovieFileOutput];
//SET THE CONNECTION PROPERTIES (output properties)
[self CameraSetOutputProperties]; //(We call a method as it also has to be done after changing camera)
//----- SET THE IMAGE QUALITY / RESOLUTION -----
//Options:
// AVCaptureSessionPresetHigh - Highest recording quality (varies per device)
// AVCaptureSessionPresetMedium - Suitable for WiFi sharing (actual values may change)
// AVCaptureSessionPresetLow - Suitable for 3G sharing (actual values may change)
// AVCaptureSessionPreset640x480 - 640x480 VGA (check its supported before setting it)
// AVCaptureSessionPreset1280x720 - 1280x720 720p HD (check its supported before setting it)
// AVCaptureSessionPresetPhoto - Full photo resolution (not supported for video output)
NSLog(@"Setting image quality");
[CaptureSession setSessionPreset:AVCaptureSessionPresetMedium];
if ([CaptureSession canSetSessionPreset:AVCaptureSessionPreset640x480]) //Check size based configs are supported before setting them
[CaptureSession setSessionPreset:AVCaptureSessionPreset640x480];
//----- DISPLAY THE PREVIEW LAYER -----
//Display it full screen under out view controller existing controls
NSLog(@"Display the preview layer");
CGRect layerRect;
layerRect = CGRectMake(284, 0, 200, 200);
[PreviewLayer setBounds:layerRect];
[PreviewLayer setPosition:CGPointMake(CGRectGetMidX(layerRect),
CGRectGetMidY(layerRect))];
//[[[self view] layer] addSublayer:[[self CaptureManager] previewLayer]];
//We use this instead so it goes on a layer behind our UI controls (avoids us having to manually bring each control to the front):
UIView *CameraView = [[UIView alloc] init];
[[self view] addSubview:CameraView];
[self.view sendSubviewToBack:CameraView];
[[CameraView layer] addSublayer:PreviewLayer];
//----- START THE CAPTURE SESSION RUNNING -----
[CaptureSession startRunning];
}
//********** CAMERA SET OUTPUT PROPERTIES **********
- (void) CameraSetOutputProperties
{
//SET THE CONNECTION PROPERTIES (output properties)
AVCaptureConnection *CaptureConnection = [MovieFileOutput connectionWithMediaType:AVMediaTypeVideo];
//Set landscape (if required)
if ([CaptureConnection isVideoOrientationSupported])
{
AVCaptureVideoOrientation orientation = AVCaptureVideoOrientationPortrait; //<<<<<SET VIDEO ORIENTATION IF LANDSCAPE
[CaptureConnection setVideoOrientation:orientation];
}
//Set frame rate (if requried)
CMTimeShow(CaptureConnection.videoMinFrameDuration);
CMTimeShow(CaptureConnection.videoMaxFrameDuration);
if (CaptureConnection.supportsVideoMinFrameDuration)
CaptureConnection.videoMinFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND);
if (CaptureConnection.supportsVideoMaxFrameDuration)
CaptureConnection.videoMaxFrameDuration = CMTimeMake(1, CAPTURE_FRAMES_PER_SECOND);
CMTimeShow(CaptureConnection.videoMinFrameDuration);
CMTimeShow(CaptureConnection.videoMaxFrameDuration);
}
//********** DID FINISH RECORDING TO OUTPUT FILE AT URL **********
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput
didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL
fromConnections:(NSArray *)connections
error:(NSError *)error
{
NSLog(@"didFinishRecordingToOutputFileAtURL - enter");
BOOL RecordedSuccessfully = YES;
if ([error code] != noErr)
{
// A problem occurred: Find out if the recording was successful.
id value = [[error userInfo] objectForKey:AVErrorRecordingSuccessfullyFinishedKey];
if (value)
{
RecordedSuccessfully = [value boolValue];
}
}
if (RecordedSuccessfully)
{
//----- RECORDED SUCESSFULLY -----
NSLog(@"didFinishRecordingToOutputFileAtURL - success");
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:outputFileURL])
{
[library writeVideoAtPathToSavedPhotosAlbum:outputFileURL
completionBlock:^(NSURL *assetURL, NSError *error)
{
if (error)
{
}
}];
}
}
}
任何帮助都会很棒