使用AVFoundation框架进行视频录制

Question

我正在使用AVFoundation框架进行视频录制项目。我正在录制640x480分辨率的视频。但录制后尺寸会发生变化。

我在做什么错？请任何人帮助我？

Answer 1

这里是我的代码 -

Here is my code :-  
#pragma mark - Configure Video Recorder method 
-(void)configureVideoRecorder{ 
    //--------------------------------- 
    //----- SETUP CAPTURE SESSION ----- 
    //--------------------------------- 
    NSLog(@"Setting up capture session"); 
    CaptureSession = [[AVCaptureSession alloc] init]; 

    [CaptureSession beginConfiguration]; 
    //----- 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 = [[[self view] layer] bounds]; 
    [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]; 

    [CaptureSession commitConfiguration]; 
    //----- START THE CAPTURE SESSION RUNNING ----- 
    [CaptureSession startRunning]; 
} 
#pragma mark - CAMERA SET OUTPUT PROPERTIES method 
- (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); 
} 

#pragma mark - GET CAMERA IN SPECIFIED POSITION IF IT EXISTS method 
- (AVCaptureDevice *) CameraWithPosition:(AVCaptureDevicePosition) Position 
{ 
    NSArray *Devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
    for (AVCaptureDevice *Device in Devices) 
    { 
     if ([Device position] == Position) 
     { 
      return Device; 
     } 
    } 
    return nil; 
} 

#pragma mark - START STOP RECORDING method 
- (void)recordVideo 
{ 
    if (!WeAreRecording) 
    { 
     //----- START RECORDING ----- 
     NSLog(@"START RECORDING"); 
     WeAreRecording = YES; 

     //Create temporary URL to record to 
     NSString *outputPath; 
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
     NSString *documentsDirectory = [paths objectAtIndex:0]; 

     outputPath = [documentsDirectory stringByAppendingFormat:@"/firstVideo.mp4"]; 

     NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outputPath]; 
     NSFileManager *fileManager = [NSFileManager defaultManager]; 
     if ([fileManager fileExistsAtPath:outputPath]) 
     { 
      NSError *error; 
      if ([fileManager removeItemAtPath:outputPath error:&error] == NO) 
      { 
       //Error - handle if requried 
      } 
     } 
     //Start recording 
     [MovieFileOutput startRecordingToOutputFileURL:outputURL recordingDelegate:self]; 
    } 
    else 
    { 
     //----- STOP RECORDING ----- 
     NSLog(@"STOP RECORDING"); 
     WeAreRecording = NO; 
     [audioPlayer stop]; 
     [MovieFileOutput stopRecording]; 
    } 
} 

#pragma mark - AVCaptureFileOutput didStartRecordingToOutputFileAtURL method 
-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections{ 
    [self playSound:selectedMp3]; 
} 

#pragma mark - DID FINISH RECORDING TO OUTPUT FILE AT URL method 
- (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"); 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:@"Video recorded successfully" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil]; 
      alert.tag = 1; 
      [alert show]; 
    } 
} 

Answer 2

试试这个

[self.avcSession setSessionPreset:AVCaptureSessionPreset640x480];