Burn in srt subtitles into a mkv-file

HandbrakeCLI-Hardsub-SRT.ps1

#COPYRIGHT: Gabriel Smoljar (2012)
#WEBSITE: http://twitter.com/gabbsmo
#DESCRIPTION: This PowerShell script process all mkv- and srt-files in a directory by
#             first converting the srt subtitles to ssa and then muxing them with their
#             corresponding mkv container in a tmp directory. The muxed mkv-files are then
#             reencoded with the subtitles burned in.
#
#NOTES: HandbrakeCLI, FFMPEG and MKVMerge must be added to PATH for this script to work.
#       Apply all parameters according to the HandbrakeCLI docs: https://trac.handbrake.fr/wiki/CLIGuide
#DEPENDENCIES: HanbrakeCLI, http://handbrake.fr; FFMPEG, http://www.ffmpeg.org; 
#              MKVMerge (included in MKVToolNix) http://www.bunkus.org/videotools/mkvtoolnix/

Param(
    [parameter(Mandatory=$true)]
    [alias("i")]
    $InputDir,
    [parameter(Mandatory=$true)]
    [alias("o")]
    $OutputDir,)
    
$items = Get-ChildItem -Path $InputDir

#Convert SRT subs to SSA
foreach ($item in $items)
{
    if ($items.Attributes -ne "Directory")
    {
        $InputFile = $InputDir + "\" + $item.name
        $OutputFile = $InputDir + "\" + $item.BaseName + ".ssa"
        
        if ($item.Extension -ieq ".srt")
        {
            ffmpeg -i $InputFile $OutputFile
        }
    }
}

#Mux SSA into MKV
foreach ($item in $items)
{
    if ($items.Attributes -ne "Directory")
    {
        $InputFile = $InputDir + "\" + $item.name
        $SubtitleFile = $InputDir + "\" +$item.BaseName + ".ssa"
        $OutputFile = $OutputDir + "\tmp\" + $item.BaseName + ".mkv"
        
        if ($item.Extension -ieq ".mkv")
        {
           mkvmerge -o $OutputFile $InputFile --language "0:eng" $SubtitleFile -s "0" -D -A
        }
    }
}

#Burn subs
$TmpDir = $OutputDir + "\tmp"
$tmp = Get-ChildItem -Path $TmpDir
foreach ($item in $tmp)
{
    if ($tmp.Attributes -ne "Directory")
    {
        $InputFile = $TmpDir + "\" + $item.name
        $OutputFile = $OutputDir + "\" + $item.BaseName + " - SD.m4v"
        
        Write-Host $InputFile
        
        if ($item.Extension -ieq ".mkv")
        {
            handbrakecli --preset "Normal" --input $InputFile --output $OutputFile --audio "1" --mixdown "stereo" --width "720" --loose-anamorphic --subtitle "1" --subtitle-burned "1"
        }
    }
}