60 fps 视频录制问题，即使它能够快速答案

【问题标题】：60 fps video recording problem even it is capable swift60 fps 视频录制问题，即使它能够快速
【发布时间】：2020-06-09 17:09:41
【问题描述】：

我正在尝试通过修改 AVCAM 应用程序来录制 60 fps 视频，该应用程序位于：

https://github.com/Lax/Learn-iOS-Swift-by-Examples/tree/master/AVCam/Swift/AVCam

因此，我的手机 (iPhone X) 通常可以达到 2-30 fps，我尝试更改它捕获视频的格式。

'''

    do {
        // Choose the back dual camera if available, otherwise default to a wide angle camera.
        if let dualCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front) {
            defaultVideoDevice = dualCameraDevice
            do{
                if let formats = defaultVideoDevice?.formats {
                    for format in formats{
                        let formatDesc = format.formatDescription
                        print(format.videoSupportedFrameRateRanges)
                        let frameRate = format.videoSupportedFrameRateRanges.first
                        print(format.formatDescription)
                        if let frameRate = frameRate, frameRate.maxFrameRate == 60.0 {
                            try defaultVideoDevice?.lockForConfiguration()
                            print(frameRate.maxFrameRate) //here prints 60.0
                            defaultVideoDevice?.activeVideoMaxFrameDuration = CMTimeMake(1,60)
                            defaultVideoDevice?.activeVideoMinFrameDuration = CMTimeMake(1,60)
                            defaultVideoDevice?.unlockForConfiguration()
                        }
                    }
                }
            }

'''

在 'defaultVideoDevice?.activeVideoMaxFrameDuration = CMTimeMake(1,60)' 行我收到此错误：

2019-11-21 09:23:50.225376+0300 AVCam[1250:667986] * 由于未捕获的异常 'NSInvalidArgumentException' 导致应用程序终止，原因：'* -[AVCaptureDevice setActiveVideoMaxFrameDuration:] 不支持帧持续时间 - 使用 -activeFormat.videoSupportedFrameRateRanges 发现有效范围'

提前致谢。

【问题讨论】：

标签： ios swift

【解决方案1】：

您应该将有效格式设置为AVCaptureDevice。

你可以这样做

// get device what you like
let device = xxxxx

// list all default formats for this device
for format in device.formats {
    var founded = false

    // check what you want and pick a perfect format. 
    let formatDesc = format.formatDescription

    // mediaType / SubType
    let mediaType = format.mediaSubType
    // if your target is above(equal) iOS 13. use formatDesc.mediaSubType
    let mediaSubType = CMFormatDescriptionGetMediaSubType(formatDesc) 

    // dimensions
    // if your target is above(equal) iOS 13. use formatDesc.dimensions
    let dimensions = CMVideoFormatDescriptionGetDimensions(formatDesc) 

    // fps
    let ranges = format.videoSupportedFrameRateRanges.first
    for supportedFPSRange in ranges {
        if supportedFPSRange.maxFrameRate == 60 {
            founded = true
        }
    }

    // support Multi cam
    let isMultiCamSupported = format.isMultiCamSupported

    ....

    if founded {
        // Set activeFormat for device! Your capture device is up and loaded.
        do {
            try device.lockForConfiguration()
            device.activeFormat = format
            device.unlockForConfiguration()
        } catch {
            // catch some locking error
        }

        // Don't forget break the loop.:p
        break
    }
}

或者你可以使用filter

【讨论】：