Question

我正在尝试使用AVAssetWriterInput创建一个带有图像输入的视频，我需要为其创建图像的像素缓冲区。

为此，我调用下面的函数，但是在创建了一些视频后，应用程序会收到内存警告并崩溃。我使用Instruments调试它，看起来我有内存泄漏here。

我曾尝试将变量pixelBufferPointer和pxData作为类变量并在创建视频后销毁/ dealloc，但这似乎没有任何区别。我应该做些什么来释放这段记忆？

func createPixelBufferFromCGImage(image: CGImageRef) -> CVPixelBufferRef {
    let options = [
        "kCVPixelBufferCGImageCompatibilityKey": true,
        "kCVPixelBufferCGBitmapContextCompatibilityKey": true
    ]

    var videoWidth = 496
    var videoHeight = 668

    let frameSize = CGSizeMake(CGFloat(videoWidth), CGFloat(videoHeight))

    var pixelBufferPointer = UnsafeMutablePointer<Unmanaged<CVPixelBuffer>?>.alloc(1)

    var status:CVReturn = CVPixelBufferCreate(
        kCFAllocatorDefault,
        Int(frameSize.width),
        Int(frameSize.height),
        OSType(kCVPixelFormatType_32ARGB),
        options,
        pixelBufferPointer
    )

    var lockStatus:CVReturn = CVPixelBufferLockBaseAddress(pixelBufferPointer.memory?.takeUnretainedValue(), 0)

    var pxData:UnsafeMutablePointer<(Void)> = CVPixelBufferGetBaseAddress(pixelBufferPointer.memory?.takeUnretainedValue())

    let bitmapinfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue)
    let rgbColorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()

    var context:CGContextRef = CGBitmapContextCreate(
        pxData,
        Int(frameSize.width),
        Int(frameSize.height),
        8,
        //4 * CGImageGetWidth(image),
        4 * Int(frameSize.width),
        rgbColorSpace,
        bitmapinfo
    )

    CGContextDrawImage(context, CGRectMake(0, 0, frameSize.width, frameSize.height), image)

    CVPixelBufferUnlockBaseAddress(pixelBufferPointer.memory?.takeUnretainedValue(), 0)

    UIGraphicsEndImageContext()

    return pixelBufferPointer.memory!.takeUnretainedValue()
}

Answer 1

查看Memory leak on CIContext createCGImage at iOS 9?

我有类似的问题，泄漏是由于以下代码

<!-- no doctype! -->
<!-- no HTML tag! we're all gonna die! -->
<head>
    <style>
        body {background:#002233;}
    </style>
</head>
<head><!-- let's twist again! -->
    <style>
        body {color:white}
    </style>
<!-- we didn't even close the second one!! -->

See this text?<br>
With the background AND color properly set?<br>
<br>
Your browser's quite a badass.

此处有更多内容相关信息：Memory Leak in CMSampleBufferGetImageBuffer

Answer 2

您不必使用UnsafeMutablePointer类型。您可能正在尝试从一些Objective-C示例转换。我做了同样的事情，但最终没有找到如何做到这一点。尝试

var pixelBufferPointer: CVPixelBuffer?
...
var status:CVReturn = CVPixelBufferCreate(
    kCFAllocatorDefault,
    Int(frameSize.width),
    Int(frameSize.height),
    OSType(kCVPixelFormatType_32ARGB),
    options,
    &pixelBufferPointer
)

和

var pxData = CVPixelBufferGetBaseAddress(pixelBufferPointer)

然后你不必做takeUnRetainedValue等。

您也可以尝试使用AVAssetWriterInputPixelBufferAdaptor和像素缓冲池。这应该更有效率。 See this example

Answer 3

Unmanaged<CVPixelBuffer>正在泄漏。

我更喜欢Russell Austin的答案，但我无法弄清楚如何将pixelBufferPointer传递给CVPixelBufferCreate而没有语法错误（swift noob）。如果做不到这一点，改变行

return pixelBufferPointer.memory!.takeUnretainedValue()

到

return pixelBufferPointer.memory!.takeRetainedValue()

修复漏洞

Answer 4

使用CVPixelBufferCreate后，UnsafeMutablePointer必须销毁后才能检索memory。

当我创建CVPixelBuffer时，我这样做：

func allocPixelBuffer() -> CVPixelBuffer {
    let pixelBufferAttributes : CFDictionary = [...]
    let pixelBufferOut = UnsafeMutablePointer<CVPixelBuffer?>.alloc(1)
    _ = CVPixelBufferCreate(kCFAllocatorDefault, 
                            Int(Width), 
                            Int(Height), 
                            OSType(kCVPixelFormatType_32ARGB),
                            pixelBufferAttributes, 
                            pixelBufferOut)

    let pixelBuffer = pixelBufferOut.memory!
    pixelBufferOut.destroy()
    return pixelBuffer
}

创建映像的像素缓冲区时内存泄漏

4 个答案: