CVPixelBuffer 到 CIImage 总是返回 nil答案

【问题标题】：CVPixelBuffer to CIImage always returning nilCVPixelBuffer 到 CIImage 总是返回 nil
【发布时间】：2013-02-25 07:52:11
【问题描述】：

我正在尝试将从 AVPlayerItemVideoOutput 提取的 pixelBuffer 转换为 CIImage 但总是为零。

守则

if([videoOutput_ hasNewPixelBufferForItemTime:player_.internalPlayer.currentItem.currentTime])
{
    CVPixelBufferRef pixelBuffer = [videoOutput_ copyPixelBufferForItemTime:player_.internalPlayer.currentItem.currentTime
                                                         itemTimeForDisplay:nil];

    CIImage *image = [CIImage imageWithCVPixelBuffer:pixelBuffer]; // Always image === nil
    CIFilter *filter = [FilterCollection filterSepiaForImage:image];
    image = filter.outputImage;

    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef cgimg = [context createCGImage:image fromRect:[image extent]];
    [pipLayer_ setContents:(id)CFBridgingRelease(cgimg)];

}

以下是用于创建 CIImage 的 pixelBuffer 的详细信息（始终导致 nil）：

$0 = 0x09b48720 <CVPixelBuffer 0x9b48720 width=624 height=352 bytesPerRow=2496 pixelFormat=BGRA iosurface=0x0 attributes=<CFBasicHash 0x98241d0 [0x1d244d8]>{type = immutable dict, count = 3,
entries =>
    0 : <CFString 0x174cf4 [0x1d244d8]>{contents = "Height"} = <CFNumber 0x9a16e70 [0x1d244d8]>{value = +352, type = kCFNumberSInt32Type}
    1 : <CFString 0x174ce4 [0x1d244d8]>{contents = "Width"} = <CFNumber 0x9a109d0 [0x1d244d8]>{value = +624, type = kCFNumberSInt32Type}
    2 : <CFString 0x1750e4 [0x1d244d8]>{contents = "PixelFormatType"} = <CFArray 0x1090ddd0 [0x1d244d8]>{type = mutable-small, count = 1, values = (
    0 : <CFNumber 0x7a28050 [0x1d244d8]>{value = +1111970369, type = kCFNumberSInt32Type}
)}
}
 propagatedAttachments=<CFBasicHash 0x9b485c0 [0x1d244d8]>{type = mutable dict, count = 6,
entries =>
    0 : <CFString 0x174ff4 [0x1d244d8]>{contents = "CVImageBufferTransferFunction"} = <CFString 0x174f84 [0x1d244d8]>{contents = "ITU_R_709_2"}
    2 : <CFString 0x174f74 [0x1d244d8]>{contents = "CVImageBufferYCbCrMatrix"} = <CFString 0x174f94 [0x1d244d8]>{contents = "ITU_R_601_4"}
    9 : <CFString 0x174f14 [0x1d244d8]>{contents = "CVPixelAspectRatio"} = <CFBasicHash 0x9b1bc30 [0x1d244d8]>{type = immutable dict, count = 2,
entries =>
    0 : <CFString 0x174f34 [0x1d244d8]>{contents = "VerticalSpacing"} = <CFNumber 0x9b0f730 [0x1d244d8]>{value = +1, type = kCFNumberSInt32Type}
    2 : <CFString 0x174f24 [0x1d244d8]>{contents = "HorizontalSpacing"} = <CFNumber 0x9b0f730 [0x1d244d8]>{value = +1, type = kCFNumberSInt32Type}
}

    10 : <CFString 0x174fb4 [0x1d244d8]>{contents = "CVImageBufferColorPrimaries"} = <CFString 0x174fd4 [0x1d244d8]>{contents = "SMPTE_C"}
    11 : <CFString 0x174e24 [0x1d244d8]>{contents = "QTMovieTime"} = <CFBasicHash 0x7a47940 [0x1d244d8]>{type = immutable dict, count = 2,
entries =>
    0 : <CFString 0x174e44 [0x1d244d8]>{contents = "TimeScale"} = <CFNumber 0x7a443d0 [0x1d244d8]>{value = +90000, type = kCFNumberSInt32Type}
    2 : <CFString 0x174e34 [0x1d244d8]>{contents = "TimeValue"} = <CFNumber 0x7a476e0 [0x1d244d8]>{value = +1047297, type = kCFNumberSInt64Type}
}

    12 : <CFString 0x174eb4 [0x1d244d8]>{contents = "CVFieldCount"} = <CFNumber 0x9b0f730 [0x1d244d8]>{value = +1, type = kCFNumberSInt32Type}
}
 nonPropagatedAttachments=<CFBasicHash 0x9b44b40 [0x1d244d8]>{type = mutable dict, count = 0,
entries =>
}
>

【问题讨论】：

标签： ios avfoundation core-image core-video

【解决方案1】：

解决了这个问题 - 我在模拟器上尝试，而它似乎只在设备上受支持。

【讨论】：

天啊...这在某处有记录吗？
这也“解决了”我的问题。在 Swift 中，我的 let inputImage = CIImage(CVPixelBuffer: pixelBuffer) 在模拟器上总是返回 nil 而在设备上返回一个对象。 :(
我什至在设备上也得到了零。谁能说出原因？
@shaun，我正在检查设备。仍然为零。你能提供任何解决方案吗？ - 普尼塔

【解决方案2】：

您似乎没有定义 iosurface 属性键。不是 100% 会解决你的问题，但试试这个：

CFDictionaryRef attrs = (CFDictionaryRef)@{
    (id)kCVPixelBufferWidthKey: @(WIDTH_OF_YOUR_VIDEO_GOES_HERE),
    (id)kCVPixelBufferHeightKey: @(HEIGHT_OF_YOUR_VIDEO_GOES_HERE),
    (id)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange;), // kCVPixelFormatType_32BGRA
    (id)kCVPixelBufferIOSurfacePropertiesKey: @{},
}

并在创建像素缓冲区期间将此字典与其他键一起传递

【讨论】：

在macos v10.10中，必须设置kCVPixelBufferPixelFormatTypeKey＝kCVPixelFormatType_32ARGB，然后+[CIImage imageWithCVPixelBuffer:]才能成功

【解决方案3】：

这不是您设置图层内容的方式；这是：

(__bridge id)uiImage.CGImage;

你不可能得到你在设备或模拟器上工作的东西。

【讨论】：