swift - AVCaptureVideoDataOutput 中的无效键 -> ProfileLevel (macOS)

Question

我正在向我的 AVCaptureVideoDataOutput 添加 key 。添加 key 时 AVVideoProfileLevelKey 系统抛出我 ->

Failed to set (contentViewController) user defined inspected property on (NSWindow): *** +[AVVideoOutputSettings videoOutputSettingsWithVideoSettingsDictionary:] Output settings dictionary contains one or more invalid keys: ProfileLevel

let captureSession = AVCaptureSession()
var videoCaptureOutput = AVCaptureVideoDataOutput()
videoCaptureOutput.videoSettings = [AVVideoCodecKey: AVVideoCodecType.h264,
                                        AVVideoWidthKey : 1280,
                                        AVVideoHeightKey : 720,
                                        AVVideoProfileLevelKey : AVVideoProfileLevelH264HighAutoLevel] as [String : Any]

key 是 AVVideoSettings.h 的一部分，AVVideoCodecKey、AVVideoWidthKey 和 AVVideoHeightKey 也是，但不清楚告诉我在哪里可以找到 AVCaptureVideoDataOutput 支持的键。

Answer 1

键及其构建方式在(键入 AVVideoCodecKey 并跳转到定​​义)中进行了描述。在你的特殊情况下 AVVideoProfileLevelKey : AVVideoProfileLevelH264HighAutoLevel 应该放在另一个字典中，这个字典应该设置为 AVVideoCompressionPropertiesKey:

let compressionSettings = [AVVideoProfileLevelKey: AVVideoProfileLevelH264HighAutoLevel]
videoCaptureOutput.videoSettings = [AVVideoCodecKey: AVVideoCodecType.h264,
                                    AVVideoWidthKey : 1280,
                                    AVVideoHeightKey : 720,
                                    AVVideoProfileLevelKey : compressionSettings]

希望对大家有帮助