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在过去的几天里，我遇到了一个让我发疯的问题。这是关于 AVAssetWriterInputPixelBufferAdaptor appendPixelBuffer 方法的。无论我做什么，它总是在这条线上导致 EXC_BAD_ACCESS。我知道有几个帖子在谈论它，但没有一个可以帮助我。

这是我的情况：我正在使用 OpenGLES 渲染到纹理中，并且我想从这些纹理中创建视频。这是我的代码：

创建 FBO，附加纹理和像素缓冲区来填充渲染：

    glGenFramebuffers(1, &_secondFrameBuffer);
glGenRenderbuffers(1, &_depthRenderBuffer);

CVPixelBufferPoolCreatePixelBuffer(NULL, [_videoWriter.pixelBufferInput pixelBufferPool], &_fboTexturePixelBuffer);
CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                             _textureCache,
                                             _fboTexturePixelBuffer,
                                             NULL,
                                             GL_TEXTURE_2D,
                                             GL_RGBA,
                                             (int)size.width,
                                             (int)size.height,
                                             GL_BGRA,
                                             GL_UNSIGNED_BYTE,
                                             0,
                                             &_fboTexture);

glBindTexture(CVOpenGLESTextureGetTarget(_fboTexture), CVOpenGLESTextureGetName(_fboTexture));
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);


glBindRenderbuffer(GL_RENDERBUFFER, _depthRenderBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, size.width, size.height);

glBindFramebuffer(GL_FRAMEBUFFER, _secondFrameBuffer);

glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, CVOpenGLESTextureGetName(_fboTexture), 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _depthRenderBuffer);

glBindFramebuffer(GL_FRAMEBUFFER, _secondFrameBuffer);

AVAssetWriter 创建：

    _dataQueue = dispatch_queue_create("data_queue", NULL);
    _assetWriter = [[AVAssetWriter alloc] initWithURL:outputURL fileType:AVFileTypeQuickTimeMovie error:nil];

    int width = [UIScreen mainScreen].applicationFrame.size.width * [UIScreen mainScreen].scale;
    int height = [UIScreen mainScreen].applicationFrame.size.height * [UIScreen mainScreen].scale;

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

    _assetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
    _assetWriterInput.expectsMediaDataInRealTime = YES;

    NSDictionary *bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                      [NSNumber numberWithInt:kCVPixelFormatType_32BGRA], kCVPixelBufferPixelFormatTypeKey,
                                      [NSNumber numberWithBool:YES], kCVPixelBufferOpenGLESCompatibilityKey,
                                      nil];

    _assetWriterInputPixelBufferAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_assetWriterInput sourcePixelBufferAttributes:bufferAttributes];


    [_assetWriter addInput:_assetWriterInput];

    _presentationTime = kCMTimeZero;
    [_assetWriter startWriting];
    [_assetWriter startSessionAtSourceTime:_presentationTime];

然后，我只是尝试附加像素缓冲区...

- (void)appendPixelBuffer:(CVPixelBufferRef)pixelBuffer
{
dispatch_async(_dataQueue, ^{

    if (pixelBuffer != NULL) {
        [_assetWriterInputPixelBufferAdaptor appendPixelBuffer:pixelBuffer    withPresentationTime:_presentationTime];
        CMTime frameTime = CMTimeMake(1, 30);
        _presentationTime = CMTimeAdd(_presentationTime, frameTime);

    } else {
        NSLog(@"NULL PixelBuffer !");
    }
});
}

崩溃 -> EXC_BAD_ACCESS

任何人都可以帮助我吗？

谢谢 ！

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1 回答 1

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我在方法中看到了您的问题- (void)appendPixelBuffer:(CVPixelBufferRef)pixelBuffer。如果您使用 ARC，请确保您的 pixelBuffer 未在异步队列上释放，以确保请尝试此代码。

- (void)appendPixelBuffer:(CVPixelBufferRef)pixelBuffer
{
   CVPixelBufferRetain(pixelBuffer);
   dispatch_async(_dataQueue, ^{
      if (pixelBuffer != NULL) {
        [_assetWriterInputPixelBufferAdaptor appendPixelBuffer:pixelBuffer    withPresentationTime:_presentationTime];
        CMTime frameTime = CMTimeMake(1, 30);
        _presentationTime = CMTimeAdd(_presentationTime, frameTime);
        CVPixelBufferRelease(pixelBuffer);
      } else {
        NSLog(@"NULL PixelBuffer !");
      }
   });
}
于 2014-06-23T09:02:45.857 回答