pwsh里用ffmpeg录制屏幕

Table of Contents

有的时候不想开obs这种大软件录制视频，就用这种ffmpeg的快捷方式，录制出来效果也还不错。

全屏录制

ffmpeg录制需要提供屏幕的大小，可以通过Get-CimInstance -Namespace root\cimv2 -ClassName Win32VideoController 获取屏幕对象$Screen，然后获取x y的值，最终保存为ScreenRecording_$Timestamp.mp4文件。 

Set-Alias recorder-screen Start-ScreenRecorder
function Start-ScreenRecorder {
    param(
        [int]$ScreenIndex = 0,
        [string]$OutputDirectory = ".\",
        [string]$Name
    )

    $Timestamp = Get-Date -Format "yyyyMMdd_HHmmss"
    $OutputFileName = "ScreenRecording_$Timestamp.mp4"
    if ($Name) {
        $OutputFileName = $Name
    }
    $OutputFilePath = Join-Path -Path $OutputDirectory -ChildPath $OutputFileName

    $Screen = Get-CimInstance -Namespace root\cimv2 -ClassName Win32_VideoController | Select-Object -Index $ScreenIndex
    $ScreenWidth = $Screen.CurrentHorizontalResolution
    $ScreenHeight = $Screen.CurrentVerticalResolution

    ffmpeg -f gdigrab -framerate 30 -video_size $ScreenWidth"x"$ScreenHeight -i desktop $OutputFilePath
}

半屏幕录制

同理，录制半屏也是通过获取屏幕的x y，然后通过ffmpeg 的 -filter参数选出自己需要的部分，下面就是录制右半边屏幕的参数。 

-filter:v "crop=in_w/2:in_h:in_w/2:0"

Set-Alias recorder-screen-right-half Start-ScreenRecorder-Right-Half
function Start-ScreenRecorder-Right-Half {
    param(
        [int]$ScreenIndex = 0,
        [string]$OutputDirectory = ".\"
    )

    $Timestamp = Get-Date -Format "yyyyMMdd_HHmmss"
    $OutputFileName = "ScreenRecording_$Timestamp.mp4"
    $OutputFilePath = Join-Path -Path $OutputDirectory -ChildPath $OutputFileName

    $Screen = Get-CimInstance -Namespace root\cimv2 -ClassName Win32_VideoController | Select-Object -Index $ScreenIndex
    $ScreenWidth = $Screen.CurrentHorizontalResolution
    $ScreenHeight = $Screen.CurrentVerticalResolution

    ffmpeg -f gdigrab -framerate 30 -video_size $ScreenWidth"x"$ScreenHeight -i desktop  -filter:v "crop=in_w/2:in_h:in_w/2:0"  $OutputFilePath
}