PowerShell batch timelapses with FFmpeg

FFmpegBatchTimelapse.ps1

# Batch process timelapses
#
### About
#
# This script will find all .mp4 files in the given directory and create an
# ./ffmpeg directory with the outputs. You can decide speed multiplier and to
# queue all files or just a few.
#
### Setup
#
# 1. Add to profile:
#   We use this script as part of our "PowerShell profile", so we can access it
#   as 'lapse' from any powershell window. Like this:
#   https://www.howtogeek.com/50236/customizing-your-powershell-profile/
#
# 2. Add 'ffmpeg' to path
#   Also important to setup 'ffmpeg' as an enviroment variable, like this:
#   https://windowsloop.com/install-ffmpeg-windows-10/
#
### How to use
#
# In PowerShell just type "lapse" and drag in the file or directory and press enter
# Example: lapse "C:\myTimelapses\"
#

function lapse($baseDir) {
  # Validation
  if (-not (Test-Path -Path $baseDir)) { echoColor "Red" "Path does not exist."; return; }
  if (Test-Path -Path $baseDir -PathType Leaf) { $baseDir = split-path $baseDir; } # Convert file path to base dir
  if (-not (Test-Path -Path $baseDir -PathType Container)) { echoColor "Red" "This does not seem to be a directory."; return; }
  $numFiles = (Get-ChildItem $baseDir -Filter *.mp4 | measure).Count;
  if ($numFiles -Eq 0) { echoColor "Red" "Found no .mp4 files in this directory."; return; }

  $outDirName = "\ffmpeg\"

  # Set speed
  $speed = 1;
  while (-not ($speed -ge 2 -and $speed -le 500)) {
    $speed = askColor "Green" 'Speed multiplier? (2-500)';
    if (-not ($speed -ge 2 -and $speed -le 500)) {
      echoColor "Red" "Invalid speed, must be a value between 2 and 500.";
    }
  }

  # Queue all files?
  $queueAll = askColor "Green" ('Queue all ' + $numFiles + ' files at x' + $speed + '? (y/n)');
  if ($queueAll.tolower() -Eq 'y') {
    #echoColor "Green" ("Queueing " + $numFiles + " files");
  } elseif (-not ($queueAll.tolower() -Eq 'n')) {
    echoColor "Yellow" "Not a valid choice, defaulting to 'no'";
    $queueAll = 'n';
  }

  # Queue individual files
  $queue = @();
  Get-ChildItem $baseDir -Filter *.mp4 | Foreach-Object {
    $queueThis = 'y';
    if ($queueAll.tolower() -Eq 'n') {
      # Test if file exsists
      $outName = $_.BaseName + ' x' + $speed + '.mp4';
      $outFile = ($baseDir + $outDirName + $outName);
      if (Test-Path -Path $outFile -PathType Leaf) {
        $queueThis = askColor "Yellow" ('Queue file "' + $_.BaseName + '" (Warning: Output file already exists) (y/n)')
      } else {
        $queueThis = askColor "Cyan" ('Queue file "' + $_.BaseName + '" (y/n)');
      }
    }
    if ($queueThis.tolower() -Eq 'y') {
      $queue += $_.BaseName;
    } elseif (-not ($queueThis.tolower() -Eq 'n')) {
      echoColor "Yellow" "Not a valid choice, defaulting to 'no'";
    }
  }

  # Check queued files
  echoColor "Green" "Queued files:";
  foreach ($name in $queue) {
    $outName = $name + ' x' + $speed + '.mp4';
    $outFile = ($baseDir + $outDirName + $outName);
    if (Test-Path -Path $outFile -PathType Leaf) {
      echoColor "Yellow" ("." + $outDirName + $outName + " (Warning: Output file already exists, will be overwritten)");
    } else {
      echoColor "Cyan" ("." + $outDirName + $outName);
    }
  }
  askColor "Green" 'Ready to process. Press enter to continue, ctrl+c to cancel';

  # Make output directory
  mkdir ($baseDir + $outDirName) > $null

  # Process files
  echoColor "Green" "Processing files...";
  foreach ($name in $queue){
    $outName = $name + ' x' + $speed + '.mp4';
    $rawFile = ($baseDir + '\' + $name + '.mp4');
    $outFile = ($baseDir + $outDirName + $outName);
    ffmpeg -y -hide_banner -loglevel warning -stats -i $rawFile -filter:v "setpts=PTS/$speed" -an $outFile
  }
  
  echoColor "Green" "Done!";
}


# Echo in color
# Example: echoColor "Red" "This text is read"
function echoColor($color, $str) {
  $tmp = $host.ui.RawUI.ForegroundColor
  $host.ui.RawUI.ForegroundColor = $color
  Write-Output $str
  $host.ui.RawUI.ForegroundColor = $tmp
}

# Question in color
# Example: askColor "Red" "Do you want to continue? (y/n)"
function askColor($color, $str) {
  $tmp = $host.ui.RawUI.ForegroundColor
  $host.ui.RawUI.ForegroundColor = $color
  $answer = Read-Host $str
  $host.ui.RawUI.ForegroundColor = $tmp
  return $answer
}

Did a recent update to this script to simplyfiy the required folder structure, and give preemptive warnings when overwriting files.