convert-webp.ps1

param(
  [string]$Year, # yyyy部分を引数として指定
  [int]$MaxParallel = 10 # 並列実行の最大数を指定（デフォルト10）
)

$sourceFolder = "N:\Users\tomachi\Pictures\VRChat"
$destinationFolder = "N:\Users\tomachi\Pictures\VRChat\webp"

$ffmpegPath = "ffmpeg"

function Wait-JobsAndUpdateProgress {
  param([array]$jobs, [int]$totalFiles)

  $completedInBatch = 0
  while ($jobs.Count -gt 0) {
    $readyJobs = $jobs | Where-Object { $_.State -eq 'Completed' }
    foreach ($job in $readyJobs) {
      $result = Receive-Job $job
      Write-Host $result
      Remove-Job $job
      $jobs = $jobs | Where-Object { $_.Id -ne $job.Id }
      $completedInBatch++
      $completedCount = $completedFiles + $completedInBatch
      Write-Progress -Activity "Converting PNG to WebP" -Status "Processing... ($completedCount/$totalFiles)" `
        -PercentComplete ($completedCount / $totalFiles * 100)
    }

    Start-Sleep -Milliseconds 500
  }

  return $completedInBatch
}

$folders = Get-ChildItem -Path $sourceFolder -Directory | Where-Object {
  $_.Name -match "^\d{4}-\d{2}$" -and $_.Name.StartsWith($Year)
}

$files = foreach ($folder in $folders) {
  Get-ChildItem -Path $folder.FullName -Filter "*.png"
}

$totalFiles = $files.Count
$completedFiles = 0

$jobs = @()

foreach ($file in $files) {
  $job = Start-Job -ScriptBlock {
    param($file, $sourceFolder, $destinationFolder, $ffmpegPath)

    $sourceFile = $file.FullName
    $relativePath = $file.DirectoryName.Substring($sourceFolder.Length).TrimStart('\')
    $destinationPath = Join-Path $destinationFolder $relativePath
    $destinationFile = Join-Path $destinationPath ([System.IO.Path]::ChangeExtension($file.Name, ".webp"))

    if (Test-Path $destinationFile) {
      return "Skipped: $destinationFile"
    }

    if (-not (Test-Path $destinationPath)) {
      New-Item -ItemType Directory -Path $destinationPath -Force | Out-Null
    }

    & $ffmpegPath -i $sourceFile -qscale:v 75 $destinationFile *>$null 2>&1

    return "Converted: $sourceFile -> $destinationFile"
  } -ArgumentList $file, $sourceFolder, $destinationFolder, $ffmpegPath

  $jobs += $job

  # 並列実行を制限
  if ($jobs.Count -ge $MaxParallel) {
    $completedFiles += Wait-JobsAndUpdateProgress $jobs $totalFiles
    $jobs = @()
  }
}

$completedFiles += Wait-JobsAndUpdateProgress $jobs $totalFiles
$jobs | Remove-Job

Write-Progress -Activity "Converting PNG to WebP" -Status "Done" -Completed
Write-Host "Conversion completed!"