AVAssetWriterInputPixelBufferAdaptor返回空像素缓冲池

Question

我确定我的缓冲区属性出了问题,但是我不清楚它是什么 - 它没有很好地记录应该去那里的东西,所以我猜是基于CVPixelBufferPoolCreate- 而Core Foundation对我来说几乎是一本封闭的书.

    // "width" and "height" are const ints
    CFNumberRef cfWidth = CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &width);
    CFNumberRef cfHeight = CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &height);

    CFStringRef keys[] = {
        kCVPixelBufferWidthKey,
        kCVPixelBufferHeightKey,
        kCVPixelBufferCGImageCompatibilityKey
    };
    CFTypeRef values[] = {
        cfWidth,
        cfHeight,
        kCFBooleanTrue
    };
    int numValues = sizeof(keys) / sizeof(keys[0]);

    CFDictionaryRef bufferAttributes = CFDictionaryCreate(kCFAllocatorDefault, 
                                                          (const void **)&keys, 
                                                          (const void **)&values,
                                                          numValues,
                                                          &kCFTypeDictionaryKeyCallBacks,
                                                          &kCFTypeDictionaryValueCallBacks
                                                          );

    AVAssetWriterInputPixelBufferAdaptor *adaptor = [[AVAssetWriterInputPixelBufferAdaptor 
                                                      assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
                                                      sourcePixelBufferAttributes:(NSDictionary*)bufferAttributes] retain];
    CVPixelBufferPoolRef bufferPool = adaptor.pixelBufferPool;
    NSParameterAssert(bufferPool != NULL); // fails

Answer 1

当pixelBufferPool返回null时,请检查以下内容:

1. AVAssetsWriter的输出文件不存在.

2.在AVAssetsWriter上调用startSessionAtTime后使用pixelbuffer.

3. AVAssetWriterInput和AVAssetWriterInputPixelBufferAdaptor的设置是正确的.

4. appendPixelBuffer使用的当前时间不一样.