Removes black bars from the video using ffmpeg

auto-crop.ps1

param (
    [Parameter(Mandatory=$true)]
    [string]$i,
    [Parameter(Mandatory=$false)]
    [switch]$preview
)

if (!(Test-Path $i)) {
    throw 'Input file does not exist: ' + $i
}

if (!(Test-Path $i -PathType Leaf)) {
    throw 'Input path is not a file: ' + $i
}

$ffmpegCommand = 'ffmpeg'
$ffplayCommand = 'ffplay'
$filename = Split-Path $i -leaf
$filepath = Split-Path $i

if ($filepath.Length -eq 0) {
    $filepath = Get-Location
}

# ffmpeg is ass with powershell
$process = New-Object System.Diagnostics.Process
$process.StartInfo.FileName = $ffmpegCommand
$process.StartInfo.Arguments = "-hide_banner -nostats -ss 1 -i ""$i"" -vframes 10 -vf cropdetect -f null -"
$process.StartInfo.UseShellExecute = $false
$process.StartInfo.RedirectStandardError = $true
$process.StartInfo.WorkingDirectory = Get-Location

Write-Host ($process.StartInfo.FileName + ' ' + $process.StartInfo.Arguments)

$process.Start() > $null
$output = $process.StandardError.ReadToEnd()
$process.WaitForExit()
    
if ($output.Trim()) {
    # search for pattern in multiline string
    $output = $output -split "`n" | Select-String -Pattern 'Parsed_cropdetect_' -SimpleMatch
    # return the right-most element
    $output = ($output -split " ")[-1]

    Write-Host $output

    if ($preview) {
        & $ffplayCommand -vf $output """$i"""
        Exit
    }

    $newFilename = "crop_$filename"
    $outPath = Join-Path $filepath $newFilename

    $process = New-Object System.Diagnostics.Process
    $process.StartInfo.FileName = $ffmpegCommand
    $process.StartInfo.Arguments = "-hide_banner -nostats -i ""$i"" -vf $output -acodec copy ""$outPath"""
    $process.StartInfo.UseShellExecute = $false
    $process.StartInfo.RedirectStandardError = $true
    $process.StartInfo.WorkingDirectory = Get-Location

    Write-Host ($process.StartInfo.FileName + ' ' + $process.StartInfo.Arguments)
    $process.Start() > $null
    $output = $process.StandardError.ReadToEnd()
    $process.WaitForExit()

    if ($output.Trim()) {
        Write-Host $output
    }
}