All 5 readers of this blog may recall my recent explorations into image formats: [1] , [2], [3], [4]. In the middle of all this, I needed to perform some batch conversion from my original screenshots into other formats or into the same format but using a different encoder.
Below is the PowerShell script I've been using. It's pretty simple. It takes one folder of images and mirrors that folder recursively with the converted format.
# ----------------------------------------
# Configuration
$srcfolder = "D:\Screenshot-Analysis\ScreenShots-PNG-Original"
$destfolder = "D:\Screenshot-Analysis\ScreenShots-WEBP-Lossless2"
$im_convert_exe = "D:\Screenshot-Analysis\ImageMagick-6.7.4-4\convert.exe"
$src_filter = "*.png"
$dest_ext = "jpeg"
$options = "-quality 90"
$logfile = "D:\convert_data.txt"
# ----------------------------------------
$fp = New-Item -ItemType file $logfile -force
$count=0
foreach ($srcitem in $(Get-ChildItem $srcfolder -include $src_filter -recurse))
{
$srcname = $srcitem.fullname
# Construct the filename and filepath for the output
$partial = $srcitem.FullName.Substring( $srcfolder.Length )
$destname = $destfolder + $partial
$destname= [System.IO.Path]::ChangeExtension( $destname , $dest_ext )
$destpath = [System.IO.Path]::GetDirectoryName( $destname )
# Create the destination path if it does not exist
if (-not (test-path $destpath))
{
New-Item $destpath -type directory | Out-Null
}
# Perform the conversion by calling an external tool
$cmdline = $im_convert_exe + " `"" + $srcname + "`"" + $options + " `"" + $destname + "`" "
#echo $cmdline
invoke-expression -command $cmdline
# Get information about the output file
$destitem = Get-item $destname
# Show and record information comparing the input and output files
$info = [string]::Format( "{0} `t {1} `t {2} `t {3} `t {4} `t {5}", $count,
$partial, $srcname, $destname, $srcitem.Length , $destitem.Length)
echo $info
Add-Content $fp $info
$count=$count+1
}