我的目标是实时在相机输入上应用一些过滤器。为了逐步做到这一点，我试图从带有 AVFoundation 的相机中获取输入，录制视频并将其保存在相机胶卷中。我试过了，但由于某种原因， AVAssetWriter 总是在 AVAssetWriterStatusFailed 中，所以 appendSampleBuffer: 方法总是失败。我的错误在哪里？有人可以帮助我吗？
谢谢！
视图控制器.h
#import <UIKit/UIKit.h>
#import <AssetsLibrary/AssetsLibrary.h>
#import <AVFoundation/AVFoundation.h>
@interface ViewController : UIViewController <AVCaptureVideoDataOutputSampleBufferDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@property (weak, nonatomic) IBOutlet UIButton *startRecButton;
@property (weak, nonatomic) IBOutlet UIButton *stopRecButton;
@property (weak, nonatomic) IBOutlet UIButton *startVideocamera;
- (IBAction)startRecordingButtonPressed:(UIButton *)sender;
- (IBAction)stopRecordingButtonPressed:(UIButton *)sender;
- (IBAction)startVideocameraButtonPressed:(UIButton *)sender;
@end
视图控制器.m
#import "ViewController.h"
@interface ViewController ()
@property (strong, nonatomic) AVAssetWriter* videoAssetWriter;
@property (strong, nonatomic) AVAssetWriterInput* videoAssetWriterInput;
@property (strong, nonatomic) NSURL* temporaryVideoURL;
@end
@implementation ViewController
#pragma mark - Variables
@synthesize imageView;
@synthesize videoAssetWriter;
@synthesize videoAssetWriterInput;
@synthesize temporaryVideoURL;
//initCaptureSession Method
AVCaptureSession* captureSession;
AVCaptureDevice* videoCaptureDevice;
AVCaptureDeviceInput* videoCaptureDeviceInput;
AVCaptureVideoDataOutput* videoDataOutput;
dispatch_queue_t videoQueue;
//captureOutput:didOutputSampleBuffer Method
CMSampleBufferRef currentSampleBuffer;
BOOL isRecording;
//newPixelBufferFromCGImage Method
CGAffineTransform frameTransform;
CGSize frameSize;
#pragma mark - User Interface
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)startRecordingButtonPressed:(UIButton *)sender {
[self initWriter];
}
- (IBAction)stopRecordingButtonPressed:(UIButton *)sender {
[self stopWriter];
}
- (IBAction)startVideocameraButtonPressed:(UIButton *)sender {
[self initCaptureSession];
}
#pragma mark - Capture Utils
-(void) initCaptureSession{
captureSession = [[AVCaptureSession alloc] init];
[captureSession setSessionPreset:AVCaptureSessionPreset1280x720];
videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError* error;
videoCaptureDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];
if([captureSession canAddInput:videoCaptureDeviceInput]){
[captureSession addInput:videoCaptureDeviceInput];
}
videoDataOutput = [[AVCaptureVideoDataOutput alloc]init];
[captureSession addOutput:videoDataOutput];
videoQueue = dispatch_queue_create("videoQueue", NULL);
[videoDataOutput setAlwaysDiscardsLateVideoFrames:NO];
[videoDataOutput setSampleBufferDelegate:self queue:videoQueue];
NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
NSDictionary* videoSettings = [NSDictionary dictionaryWithObject:value forKey:key];
[videoDataOutput setVideoSettings:videoSettings];
[captureSession startRunning];
}
-(void) captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer: (CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
currentSampleBuffer = sampleBuffer;
CGImageRef image = [self imageFromSampleBuffer:currentSampleBuffer];
dispatch_sync(dispatch_get_main_queue(),
^{
if(!isRecording){
imageView.image = [UIImage imageWithCGImage: image scale:1.0 orientation:UIImageOrientationRight];
}
else{
imageView.image = [UIImage imageWithCGImage: image scale:1.0 orientation:UIImageOrientationRight];
// [videoAssetWriterInput appendSampleBuffer:currentSampleBuffer];
if (![videoAssetWriterInput appendSampleBuffer:sampleBuffer]) {
[self showError:[videoAssetWriter error]];
}
NSLog(@"%ld", (long)[videoAssetWriter status]);
}
});
CGImageRelease(image);
}
-(void)captureOutput:(AVCaptureOutput *)captureOutput didDropSampleBuffer: (CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
NSLog(@"didDropSampleBuffer CALLED");
}
#pragma mark - Writer Utils
-(void) initWriter{
temporaryVideoURL = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@%@", NSTemporaryDirectory(), @"Movie.MOV"]];
NSLog(@"%@", temporaryVideoURL);
NSError* error;
videoAssetWriter = [[AVAssetWriter alloc] initWithURL:temporaryVideoURL fileType:AVFileTypeQuickTimeMovie error:&error];
NSParameterAssert(videoAssetWriter);
NSLog(@"%ld", (long)[videoAssetWriter status]);
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:1280], AVVideoWidthKey,
[NSNumber numberWithInt:720], AVVideoHeightKey,
nil];
videoAssetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
NSParameterAssert(videoAssetWriterInput);
NSLog(@"%ld", (long)[videoAssetWriter status]);
if([videoAssetWriter canAddInput:videoAssetWriterInput]){
[videoAssetWriter addInput:videoAssetWriterInput];
}
isRecording = YES;
[videoAssetWriter startWriting];
NSLog(@"%ld", (long)[videoAssetWriter status]);
}
-(void) stopWriter{
[videoAssetWriterInput markAsFinished];
[videoAssetWriter finishWritingWithCompletionHandler:^{
NSLog(@"finishWritingWithCompletionHandler CALLED");
isRecording = NO;
[self saveVideoToCameraRoll];
videoAssetWriter =nil;
videoAssetWriterInput= nil;
}];
// [videoAssetWriter finishWriting];
// isRecording = NO;
// [self saveVideoToCameraRoll];
}
-(void) saveVideoToCameraRoll{
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:temporaryVideoURL completionBlock:^(NSURL *assetURL, NSError *error){
NSLog(@"ASSET URL: %@", [assetURL path]);
if(error) {
NSLog(@"CameraViewController: Error on saving movie : %@ {imagePickerController}", error);
}
else {
NSLog(@"Video salvato correttamente in URL: %@", assetURL);
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:[temporaryVideoURL path]];
NSLog(@"IL FILE ESISTE: %hhd", fileExists);
NSLog(@"E PESA: %@", [[[NSFileManager defaultManager] attributesOfItemAtPath: [temporaryVideoURL path] error:&error] objectForKey:NSFileSize]);
}
}];
}