FFmpeg: convert video to .mp4 (PowerShell script)

ffmpeg_2mp4.ps1

# convert video to .mp4 (x264)
# copies audio stream

param(
  [Parameter(Mandatory=$true)][string]$InputPath,
  [string]$OutputPath,
  [int]$Height=0, # 0 for input height
  [switch]$Fast=$false
)

if(-not $OutputPath) {
  $OutputPath = [System.IO.Path]::ChangeExtension($InputPath, "mp4")
}

$filters = "scale=-1:${Height}:flags=lanczos"
$preset = if($Fast) { 'faster' } else { 'slow' }

ffmpeg -y -v warning -i $InputPath -vf $filters -c:v libx264 -preset $preset -crf 18 -c:a copy $OutputPath