相关疑难解决方法(0)

当我使用AVCaptureVideoDataOutput和AVCaptureAudioDataOutput录制音频+视频时,我遇到了延迟问题.有时视频会阻塞几毫秒,有时音频与视频不同步.

我插入了一些日志并观察到我首先在captureOutput回调中获得了大量视频缓冲区,并且在一段时间后我得到了音频缓冲区(有时我根本没有收到音频缓冲区,结果视频没有声音).如果我评论处理视频缓冲区的代码,我会毫无问题地获得音频缓冲区.

这是我正在使用的代码:

-(void)initMovieOutput:(AVCaptureSession *)captureSessionLocal
{   
    AVCaptureVideoDataOutput *dataOutput = [[AVCaptureVideoDataOutput alloc] init];
    self._videoOutput = dataOutput;
    [dataOutput release];

    self._videoOutput.alwaysDiscardsLateVideoFrames = NO;
    self._videoOutput.videoSettings = [NSDictionary dictionaryWithObject: [NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange]
                                                             forKey:(id)kCVPixelBufferPixelFormatTypeKey
                                  ];     
    AVCaptureAudioDataOutput *audioOutput =  [[AVCaptureAudioDataOutput alloc] init];
    self._audioOutput = audioOutput;
    [audioOutput release];

    [captureSessionLocal addOutput:self._videoOutput];
    [captureSessionLocal addOutput:self._audioOutput];


    // Setup the queue
    dispatch_queue_t queue = dispatch_queue_create("MyQueue", NULL);
    [self._videoOutput setSampleBufferDelegate:self queue:queue];
    [self._audioOutput setSampleBufferDelegate:self queue:queue];
    dispatch_release(queue);
}

在这里我设置了作者:

-(BOOL) setupWriter:(NSURL *)videoURL session:(AVCaptureSession *)captureSessionLocal
{
    NSError *error = nil;
    self._videoWriter = [[AVAssetWriter alloc] initWithURL:videoURL fileType:AVFileTypeQuickTimeMovie
                                                         error:&error];
    NSParameterAssert(self._videoWriter);


    // …

#import "VTM_AViPodReaderViewController.h"
#import <AudioToolbox/AudioToolbox.h> // for the core audio constants


#define EXPORT_NAME @"exported.caf"

@implementation VTM_AViPodReaderViewController

@synthesize songLabel;
@synthesize artistLabel;
@synthesize sizeLabel;
@synthesize coverArtView;
@synthesize conversionProgress;


#pragma mark init/dealloc
- (void)dealloc {
    [super dealloc];
}

#pragma mark vc lifecycle

-(void) viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
}

#pragma mark event handlers

-(IBAction) convertTapped: (id) sender {
    // set up an AVAssetReader to read from the iPod Library
    NSURL *assetURL = [song valueForProperty:MPMediaItemPropertyAssetURL];
    AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL options:nil];

    NSError *assetError = nil;
    AVAssetReader …