标签: avassetwriter

我一直在尝试使用AVAssetWriter和AVAssetWriterInputs编写视频+音频.

我在这个论坛上看了很多人说他们能够做到这一点,但这对我不起作用.如果我只是写视频,那么代码就能很好地完成它的工作.当我添加音频时,输出文件已损坏且无法再现.

这是我的代码的一部分:

设置AVCaptureVideoDataOutput和AVCaptureAudioDataOutput:

NSError *error = nil;

// Setup the video input
AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeVideo];
// Create a device input with the device and add it to the session.
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
// Setup the video output
_videoOutput = [[AVCaptureVideoDataOutput alloc] init];
_videoOutput.alwaysDiscardsLateVideoFrames = NO;
_videoOutput.videoSettings =
[NSDictionary dictionaryWithObject:
[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];     

// Setup the audio input
AVCaptureDevice *audioDevice     = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeAudio];
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error ];     
// Setup the …

我正在尝试使用图片阵列和音频文件制作电影文件.为了制作带有图片阵列的电影,我在这里使用了zoul的大帖子.一切都很完美,我的电影和我的照片一样.但是,当我尝试添加一些音轨时,我遇到了很多问题.要理解我把我的代码:

当我调用此方法时,图片数组和歌曲文件已准备就绪:

-(void) writeImagesToMovieAtPath:(NSString *) path withSize:(CGSize) size
{
    NSString *documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSArray *dirContents = [[NSFileManager defaultManager] directoryContentsAtPath:documentsDirectoryPath];
    for (NSString *tString in dirContents) {
        if ([tString isEqualToString:@"essai.mp4"]) 
        {
            [[NSFileManager defaultManager]removeItemAtPath:[NSString stringWithFormat:@"%@/%@",documentsDirectoryPath,tString] error:nil];

        }
    }

    NSLog(@"Write Started");

    NSError *error = nil;

    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                                  [NSURL fileURLWithPath:path] fileType:AVFileTypeMPEG4
                                                              error:&error];    
    NSParameterAssert(videoWriter);

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:size.width], AVVideoWidthKey,
                                   [NSNumber numberWithInt:size.height], AVVideoHeightKey,
                                   nil];

    AudioChannelLayout channelLayout;
    memset(&channelLayout, 0, sizeof(AudioChannelLayout));
    channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;

    NSDictionary …

我必须从我的iPhone应用程序导出一部电影,其中包含来自NSArray的UIImage,并添加一些必须在预先指定的时间开始的.caf格式的音频文件.现在我已经能够使用AVAssetWriter导出包含图像的视频部分(经历就这个问题和其他网站的许多问题和答案后),但不能似乎找到一个方法来添加音频文件来完成电影.

这是我到目前为止所得到的

-(void) writeImagesToMovieAtPath:(NSString *) path withSize:(CGSize) size
{
    NSLog(@"Write Started");

    NSError *error = nil;

    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                              [NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
                                                          error:&error];    
    NSParameterAssert(videoWriter);

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:size.width], AVVideoWidthKey,
                               [NSNumber numberWithInt:size.height], AVVideoHeightKey,
                               nil];

    AVAssetWriterInput* videoWriterInput = [[AVAssetWriterInput
                                    assetWriterInputWithMediaType:AVMediaTypeVideo
                                    outputSettings:videoSettings] retain];


    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
                                            assetWriterInputPixelBufferAdaptorWithAssetWriterInput:videoWriterInput
                                                 sourcePixelBufferAttributes:nil];

    NSParameterAssert(videoWriterInput);
    NSParameterAssert([videoWriter canAddInput:videoWriterInput]);
    videoWriterInput.expectsMediaDataInRealTime = YES;
    [videoWriter addInput:videoWriterInput];

    //Start a session:
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];

    CVPixelBufferRef buffer = NULL;

    //convert uiimage to CGImage.

    int frameCount = 0; …

从Apple文档中它只是说:

当此属性的值为YES时,将以这样的方式写入输出文件,即只在下载少量文件后才能开始播放.

但究竟发生了什么？

我有一个功能,应该在iphone/ipad上将视频重新编码为可管理的比特率.这是:*更新的工作代码,现在有音频!:)*

    -(void)resizeVideo:(NSString*)pathy{
    NSString *newName = [pathy stringByAppendingString:@".down.mov"];
    NSURL *fullPath = [NSURL fileURLWithPath:newName];
    NSURL *path = [NSURL fileURLWithPath:pathy];


    NSLog(@"Write Started");

    NSError *error = nil;

    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:fullPath fileType:AVFileTypeQuickTimeMovie error:&error];    
    NSParameterAssert(videoWriter);
    AVAsset *avAsset = [[[AVURLAsset alloc] initWithURL:path options:nil] autorelease];
    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:1280], AVVideoWidthKey,
                                   [NSNumber numberWithInt:720], AVVideoHeightKey,
                                   nil];

    AVAssetWriterInput* videoWriterInput = [[AVAssetWriterInput
                                             assetWriterInputWithMediaType:AVMediaTypeVideo
                                             outputSettings:videoSettings] retain];
    NSParameterAssert(videoWriterInput);
    NSParameterAssert([videoWriter canAddInput:videoWriterInput]);
    videoWriterInput.expectsMediaDataInRealTime = YES;
    [videoWriter addInput:videoWriterInput];
    NSError *aerror = nil;
    AVAssetReader *reader = [[AVAssetReader alloc] …

我想导出一部电影,AVAssetWriter但无法弄清楚如何同步包含视频和音频轨道.仅导出视频工作正常,但是当我添加音频时,生成的电影如下所示:

首先,我看到视频(没有音频),然后视频冻结(显示最后一个图像帧直到结束),几秒钟后我听到音频.

我尝试了一些事情CMSampleBufferSetOutputPresentationTimeStamp(CMSampleBufferGetPresentationTimeStamp从当前减去第一个)用于音频,但这一切都不起作用,我认为这不是正确的方向,因为源电影中的视频和音频应该是同步的. ..

我的设置简单:我创建一个AVAssetReader和2 AVAssetReaderTrackOutput(一个用于视频,一个用于音频)并将它们添加到AVAssetReader,然后我创建一个AVAssetWriter和2 AVAssetWriterInput(视频和音频)并将它们添加到AVAssetWriter...我开始一切:

[assetReader startReading];
[assetWriter startWriting];
[assetWriter startSessionAtSourceTime:kCMTimeZero];

然后我运行2个队列来做样本缓冲区的东西:

dispatch_queue_t queueVideo=dispatch_queue_create("assetVideoWriterQueue", NULL);
[assetWriterVideoInput requestMediaDataWhenReadyOnQueue:queueVideo usingBlock:^
{
     while([assetWriterVideoInput isReadyForMoreMediaData])
     {
         CMSampleBufferRef sampleBuffer=[assetReaderVideoOutput copyNextSampleBuffer];
         if(sampleBuffer)
         {
             [assetWriterVideoInput appendSampleBuffer:sampleBuffer];
             CFRelease(sampleBuffer);
         } else
         {
             [assetWriterVideoInput markAsFinished];
             dispatch_release(queueVideo);
             videoFinished=YES;
             break;
         }
     }
}];

dispatch_queue_t queueAudio=dispatch_queue_create("assetAudioWriterQueue", NULL);
[assetWriterAudioInput requestMediaDataWhenReadyOnQueue:queueAudio usingBlock:^
{
    while([assetWriterAudioInput isReadyForMoreMediaData])
    {
        CMSampleBufferRef sampleBuffer=[assetReaderAudioOutput copyNextSampleBuffer];
        if(sampleBuffer)
        {
            [assetWriterAudioInput appendSampleBuffer:sampleBuffer];
            CFRelease(sampleBuffer);
        } else
        { …

我有一个奇怪的记忆"泄漏" AVAssetWriterInput appendSampleBuffer.我正在同时写视频和音频,所以我有一个AVAssetWriter有两个输入,一个用于视频,一个用于音频:

self.videoWriter = [[[AVAssetWriter alloc] initWithURL:[self.currentVideo currentVideoClipLocalURL]
                                              fileType:AVFileTypeMPEG4
                                                 error:&error] autorelease];
...
self.videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo
                                                           outputSettings:videoSettings];
self.videoWriterInput.expectsMediaDataInRealTime = YES;
[self.videoWriter addInput:self.videoWriterInput];
...
self.audioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio
                                                           outputSettings:audioSettings];
self.audioWriterInput.expectsMediaDataInRealTime = YES;
[self.videoWriter addInput:self.audioWriterInput];

我开始写作,表面上的一切都很好.视频和音频被写入并对齐等等.但是,我将我的代码放入分配工具并注意到以下内容:

音频字节将保留在内存中,我将在一秒钟内证明.这是内存中的增长.音频字节仅在我调用后才会释放[self.videoWriter endSessionAtSourceTime:...],您会看到内存使用量急剧下降.这是我的音频编写代码,它作为一个块被分派到一个串行队列:

@autoreleasepool
{
    // The objects that will hold the audio data
    CMSampleBufferRef sampleBuffer;
    CMBlockBufferRef  blockBuffer1;
    CMBlockBufferRef  blockBuffer2;

    size_t nbytes = numSamples * asbd_.mBytesPerPacket;

    OSStatus status = noErr;
    status = CMBlockBufferCreateWithMemoryBlock(kCFAllocatorDefault,
                                                data,
                                                nbytes,
                                                kCFAllocatorNull,
                                                NULL,
                                                0,
                                                nbytes,
                                                kCMBlockBufferAssureMemoryNowFlag,
                                                &blockBuffer1); …

我正在使用AVAssetWriter,它完全适用于iOS6.

问题是,当我打电话时finishWritingWithCompletionHandler,iOS7 GM上没有调用完成处理程序.

我打电话markAsFinished,甚至endSessionAtSourceTime在我调用finishWritingWithCompletionHandler之前.

它在iOS6上运行良好.

甚至更多,在iOS7上,它可以工作一段时间,然后它再也不起作用了.

我不知道为什么,但如果我使用警报视图调用该方法,它就可以工作.于是,我就performSelectorOnMainThread和inBackground,但它并没有帮助.

有任何想法吗？

我想拍摄一些视频帧并将它们编码成视频.看起来这正是它的AVAssetWriter意思,但无论我如何看待文档和谷歌我都找不到任何方法来实际使用它.从文档中看起来我需要一个input(AVAssetWriterInput)来从中提供编写器.精细.但是这个AVAssetWriterInput类是抽象的,我在4.1中知道的唯一子类是AVAssetWriterInputPixelBufferAdaptor它AVAssetWriterInput在初始化器中需要一个......？我错过了一些明显的东西吗？

一直试图弄明白这一点,但没有成功.

我可以写视频输出没问题...但是一旦我尝试引入第二个AVAssetWriterInput来包含音频,最后的quicktime电影是跳跃的,帧左右丢失,音频不断进出.

谢谢 - wg