Remove-FFMpegVideoFileAudioStream -Dir "C:\\Media\\Movies" -VideoFile "Alien (1979).mkv" -AudioStreamIx 0

Get-ChildItem -Path "C:\\Media\\Shows\\Season 01" -Directory |
    ForEach-Object { $_.FullName } |
        Remove-FFMpegVideoFileAudioStream -AudioStreamIx 0

Get-FFProbeAudioStreams -VideoFile "C:\\Media\\Movies\\Alien (1979).mkv" |
    Where-Object { $_.index -eq 1 } |
        Remove-FFMpegVideoFileAudioStream

<#
.SYNOPSIS
Removes an audio stream from a video file by index. Outputs a copy of the input file with 'asr-' prefix on the filename. Supports pipeline input from Get-FFProbeAudioStreams.

.DESCRIPTION
Removes an audio stream from a video file by index. Outputs a copy of the input file with 'asr-' prefix on the filename. Can accept pipeline input from Get-FFProbeAudioStreams for automated processing.

.PARAMETER Dirs
Multiple directories containing files. No recurse, so only one level. Overrides Dir parameter if supplied.

.PARAMETER Dir
The directory the file is located in. Defaults to current location if not supplied.

.PARAMETER VideoFile
The video file name. Iterates every file in the directory if not supplied.

.PARAMETER VideoStreamIx
Index of the video stream. Defaults to 0.

.PARAMETER AudioStreamIx
Index of the audio stream to remove.

.PARAMETER ThrottleLimit
Degree of parallelism. Defaults to 20.

.PARAMETER File
Full path to the video file (for pipeline input).

.PARAMETER Index
Index of the audio stream to remove (for pipeline input).

.PARAMETER VideoStreamIxPipeline
Index of the video stream for pipeline input. Defaults to 0.

.EXAMPLE
Where non-english is the first audio stream:
Remove-FFMpegVideoFileAudioStream -Dir "C:\movies\Alien (1979)" -VideoFile "Alien (1979).mkv" -AudioStreamIx 0

.EXAMPLE
Where non-english is the first audio stream and all season folders in show:
Get-ChildItem -Path "Y:\complete\The Americans" -Directory |
    ForEach-Object { $_.FullName } |
        Remove-FFMpegVideoFileAudioStream -AudioStreamIx 0

.EXAMPLE
Using pipeline from Get-FFProbeAudioStreams to remove the first audio stream:
Get-FFProbeAudioStreams -VideoFile "C:\movies\Alien (1979).mkv" | Where-Object { $_.index -eq 1 } | Remove-FFMpegVideoFileAudioStream

#>
function Remove-FFMpegVideoFileAudioStream {
    [CmdletBinding(DefaultParameterSetName = 'Directory')]
    param (
        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $true, Position = 0, HelpMessage = "Multiple directories containing files. No recurse, so only one level. Overrides Dir parameter if supplied")]
        [string[]]$Dirs,

        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $false, HelpMessage = "The directory the file is located in. Defaults to current location if not supplied.")]
        [string]$Dir,

        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $false, HelpMessage = "The video file name. Iterates every file in the directory if not supplied.")]
        [string]$VideoFile,

        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $false, HelpMessage = "Index of the video stream. Defaults to 0.")]
        [int]$VideoStreamIx = 0,

        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $false, Mandatory = $true, HelpMessage = "Index of the audio stream to remove.")]
        [int]$AudioStreamIx,

        [Parameter(ParameterSetName = 'Directory', ValueFromPipeline = $false, HelpMessage = "Degree of parallelism. Defaults to 20.")]
        [int]$ThrottleLimit = 20,

        [Parameter(ParameterSetName = 'Pipeline', ValueFromPipelineByPropertyName = $true, HelpMessage = "Full path to the video file.")]
        [string]$File,

        [Parameter(ParameterSetName = 'Pipeline', ValueFromPipelineByPropertyName = $true, HelpMessage = "Index of the audio stream to remove.")]
        [int]$Index,

        [Parameter(ParameterSetName = 'Pipeline', ValueFromPipeline = $false, HelpMessage = "Index of the video stream. Defaults to 0.")]
        [int]$VideoStreamIxPipeline = 0
    )

    begin {
        $Checkpoint = Get-Location
    }

    process {
        if ($PSCmdlet.ParameterSetName -eq 'Pipeline') {
            # handle pipeline input
            $Dir = Split-Path $File
            $VideoFile = Split-Path $File -Leaf
            $AudioStreamIx = $Index
            $VideoStreamIx = $VideoStreamIxPipeline

            $asrDir = Join-Path $Dir 'ASR'
            New-Item -ItemType Directory -Path $asrDir -Force | Out-Null

            $inputPath = Join-Path $Dir $VideoFile
            $outputPath = Join-Path $asrDir $VideoFile

            $command = "ffmpeg -i `"$inputPath`" -map $VideoStreamIx -map -$VideoStreamIx`:a:$AudioStreamIx -c copy `"$outputPath`""
            Write-Host $command
            Start-Process -FilePath 'powershell' -ArgumentList "-command $command" -Wait -NoNewWindow -PassThru
            return
        }

        Function EscapeSingleQuotes {
            [CmdletBinding()]
            param (
                [Parameter(ValueFromPipeline = $true, Position = 0, HelpMessage = "String to escape single quotes in.")]
                [string]$String
            )

            Process {
                return $String.Replace("'", "``'")
            }
        }

        if ($null -eq $Dirs) {
            # perform processing on a single directory

            if ([String]::IsNullOrWhiteSpace($Dir)) {
                $Dir = Get-Location
            }
            else {
                Set-Location $Dir
            }

            Write-Host "Processing files in $($Dir)..."

            $asrDir = $(Join-Path -Path $Dir -ChildPath 'ASR')

            mkdir $asrDir -Force

            # perform processing on single video file
            if (-Not [String]::IsNullOrWhiteSpace($VideoFile)) {
                ffmpeg -i $(Join-Path -Path $Dir -ChildPath $VideoFile) -map $VideoStreamIx -map -$VideoStreamIx:a:$AudioStreamIx -c copy $(Join-Path -Path $asrDir -ChildPath $VideoFile)

                return
            }

            # perform processing on all files in directory
            #Get-ChildItem -Path $Dir -File | ForEach-Object -ThrottleLimit $ThrottleLimit -Parallel {
            Get-ChildItem -Path $Dir -File | ForEach-Object {
                $cleanFullName = EscapeSingleQuotes -String $_.FullName

                $asrFile = $($cleanFullName).Replace($($_.Name), $(Join-Path -Path 'ASR' -ChildPath $($_.Name)))

                $command = "ffmpeg -i `"$($cleanFullName)`" -map $VideoStreamIx -map -$($VideoStreamIx):a:$($AudioStreamIx) -c copy `"$asrFile`""

                Write-Host $command

                Start-Process -FilePath 'powershell' -ArgumentList "-command $command" -Wait -NoNewWindow -PassThru
            }

            return
        }

        # perform processing on multiple directories
        $Dirs | ForEach-Object {
            Write-Host "Processing files in $($_)..."

            Set-Location $_

            $asrDir = $(Join-Path -Path $_ -ChildPath 'ASR')

            mkdir $asrDir -Force -InformationAction SilentlyContinue

            Get-ChildItem -Path $_ -File |
            ForEach-Object {
                $asrFile = $($_.FullName).Replace($($_.Name), $(Join-Path -Path 'ASR' -ChildPath $($_.Name)))

                $command = "ffmpeg -i `"$($($_.FullName))`" -map $VideoStreamIx -map -$($VideoStreamIx):a:$($AudioStreamIx) -c copy `"$asrFile`""

                Start-Process -FilePath 'powershell' -ArgumentList "-command $command" -Wait -NoNewWindow -PassThru

                #ffmpeg -i $($_.FullName) -map $VideoStreamIx -map -$($VideoStreamIx):a:$($AudioStreamIx) -c copy ($asrFile)
            }

            # ffmpeg doesn't like working in parallel threads, investigate at a time you can be arsed to work out why

            # Get-ChildItem -Path $_ -File |
            #     ForEach-Object -ThrottleLimit $ThrottleLimit -Parallel {
            #         $asrFile = $($PSItem.FullName).Replace($($PSItem.Name), $(Join-Path -Path 'ASR' -ChildPath $($PSItem.Name)))

            #         ffmpeg -i $($PSItem.FullName) -map $VideoStreamIx -map -$VideoStreamIx:a:$AudioStreamIx -c copy $asrFile
            #     }
        }
    }

    end {
        Set-Location $Checkpoint
    }
}