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。我正在录制分辨率为 640x480 的视频。但是在记录之后尺寸发生了变化。

我做错了什么？请任何人帮助我？

Answer 1

试试这个

[self.avcSession setSessionPreset:AVCaptureSessionPreset640x480];

Answer 2

这是我的代码 -

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];
    }
}

使用 AVFoundation 框架进行视频录制

Video recording using AVFoundation framework

video-capture

objective-c

avfoundation

ios