1

我正在尝试从视频中获取一组帧。这是我的代码：

        var frames = [UIImage]()

        let url    = NSBundle.mainBundle().URLForResource(name, withExtension: ext, subdirectory: "Assets")!
        let asset  = AVAsset(URL: url)
        let reader = try AVAssetReader(asset: asset)
        let output = AVAssetReaderVideoCompositionOutput(videoTracks: asset.tracksWithMediaType(AVMediaTypeVideo), videoSettings: nil)
        output.videoComposition = AVVideoComposition(propertiesOfAsset: asset)
        reader.addOutput(output)
        reader.startReading()

        let frameCount = Int(asset.duration.seconds*23.973)
        let context    = CIContext()

        print("Asset reader: \(reader.error)")
        for _ in 0..<frameCount{
            let buff        = output.copyNextSampleBuffer()
            if buff == nil{

                continue
            }
            let pixelBuffer = CMSampleBufferGetImageBuffer(buff!)! as CVPixelBuffer
            let ciImage     = CIImage(CVPixelBuffer: pixelBuffer)
            let cgImgRef    = context.createCGImage(ciImage, fromRect: CGRectMake(0, 0, CGFloat(CVPixelBufferGetWidth(pixelBuffer)), CGFloat(CVPixelBufferGetHeight(pixelBuffer))))
            frames.append(UIImage(CGImage: cgImgRef))
        }

当我尝试使用.mp4时，它可以正常工作，但是当我想使用.mov（我需要 alpha 通道）时，它会说：

Error Domain=AVFoundationErrorDomain Code=-11833 "Cannot Decode" UserInfo={NSLocalizedFailureReason=The decoder required for this media cannot be found., NSUnderlyingError=0x15e77fb90 {Error Domain=NSOSStatusErrorDomain Code=-12906 "(null)"}, AVErrorMediaTypeKey=vide, NSLocalizedDescription=Cannot Decode})

我已尝试使用 Premiere Pro 中支持透明度和像素格式kCVPixelFormatType_32RGBA、kCVPixelFormatType_32BGRA、kCVPixelFormatType_32ARG 和 kCVPixelFormatType_32ABGR的所有编解码器，但仍然出现相同的错误。有什么建议吗？

4

0 回答 0