Add -Crop parameter to Clone-Video.ps1 for center-cropping instead of resizing when combined with -Size, implementing Get-SizeFilter function that crops only dimensions larger than requested size with even-number rounding, applying crop filter across image-to-video, PNG sequence, and standard video modes, and updating documentation and output messages to indicate cropped dimensions

Clone-Video.ps1

@@ -14,11 +14,11 @@
     from the image sequence, ordered alphabetically (or reverse alphabetically if -Reverse is specified).
     - -Sequence and -Metadata are not allowed in this mode.
     - Defaults: 24 FPS, CRF 8, no audio (unless -Audio is provided).
-    - -Size, -FPS, -CRF, -Audio, -NoAudio, -StartFrame, -EndFrame, -Frames, -Reverse and -LTX are all honoured.
+    - -Size, -FPS, -CRF, -Audio, -NoAudio, -StartFrame, -EndFrame, -Frames, -Reverse, -LTX and -Crop are all honoured.
     When Source is a supported image file (.png, .jpg, .jpeg, .webp, .bmp, .tiff, .tif, .gif) and Audio is provided, the script builds a video of the static image for the duration of the audio file.
     - -NoAudio is not allowed in this mode.
     - Defaults: 24 FPS, CRF 8, source image dimensions.
-    - -Size, -FPS, -CRF and -LTX are honoured.
+    - -Size, -FPS, -CRF, -LTX and -Crop are honoured.
     - -StartFrame, -EndFrame, -Frames, -Sequence, -Metadata and -Reverse are ignored.
 .PARAMETER Source
     Path to the input video file, or a directory containing PNG files with sequence numbers (e.g. frame_0000.png).
@@ -74,6 +74,16 @@
     - 720p:       1280x704  (16:9), 704x1280  (9:16), 1088x576 (21:9), 576x1088 (9:21)
     - 480p:       832x448   (16:9), 448x832   (9:16), 896x512  (4:3),  512x896  (3:4)
     Forces a video re-encode (same as -Size).
+.PARAMETER Crop
+    When present, the dimensions selected by -Size (including -LTX buckets) are obtained by center-cropping
+    the source instead of resizing it, so the original pixel aspect ratio is kept (no stretching or scaling).
+    Each dimension is cropped only when the source is bigger than the requested size; a dimension where the
+    source is equal or smaller is left untouched (no upscaling or padding). Cropped dimensions are rounded
+    down to an even number. Examples for a 1080x1080 source:
+    - -Size 960:1080 -Crop: cropped horizontally to 960x1080.
+    - -Size 720:720 -Crop:  cropped horizontally and vertically to 720x720.
+    Requires -Size. Without -Crop, the source is resized (default behaviour).
+    Forces a video re-encode (same as -Size).
 .DESCRIPTION
     This script uses ffmpeg to clone (copy) a video file with optional frame range and audio exclusion.
     When Sequence is provided, it extracts a specific frame to PNG and then clones the video accordingly.
@@ -123,7 +133,10 @@ param(
     [switch]$Reverse,
 
     [Parameter(Mandatory = $false)]
-    [switch]$LTX
+    [switch]$LTX,
+
+    [Parameter(Mandatory = $false)]
+    [switch]$Crop
 )
 
 Set-StrictMode -Version Latest
@@ -271,6 +284,31 @@ if (-not [string]::IsNullOrWhiteSpace($Size)) {
     }
 }
 
+if ($Crop -and [string]::IsNullOrWhiteSpace($Size)) {
+    Write-Error '-Crop requires -Size'
+    exit 1
+}
+
+# Builds the ffmpeg size filter for the requested output dimensions.
+# Without -Crop the source is resized (scale). With -Crop the source is center-cropped,
+# only on the dimensions where it is bigger than the requested size.
+function Get-SizeFilter {
+    param([int]$SrcWidth, [int]$SrcHeight, [int]$OutWidth, [int]$OutHeight)
+    if (-not $Crop) {
+        return @{ Filter = ('scale={0}:{1}' -f $OutWidth, $OutHeight); Width = $OutWidth; Height = $OutHeight }
+    }
+    if ($SrcWidth -le 0 -or $SrcHeight -le 0) {
+        Write-Error 'Could not determine source dimensions; -Crop cannot compute the crop area.'
+        exit 1
+    }
+    $cropWidth  = [Math]::Min($OutWidth, $SrcWidth)
+    $cropHeight = [Math]::Min($OutHeight, $SrcHeight)
+    $cropWidth  -= $cropWidth % 2
+    $cropHeight -= $cropHeight % 2
+    return @{ Filter = ('crop={0}:{1}' -f $cropWidth, $cropHeight); Width = $cropWidth; Height = $cropHeight }
+}
+$cropNote = if ($Crop) { ' (cropped)' } else { '' }
+
 $PSNativeCommandUseErrorActionPreference = $false
 
 # Image-to-video mode: when $Source is a supported image file and $Audio is provided.
@@ -356,6 +394,12 @@ if (($supportedImageExts -contains $sourceExt) -and $AudioPath) {
     if ($imgOutWidth % 2)  { $imgOutWidth++ }
     if ($imgOutHeight % 2) { $imgOutHeight++ }
 
+    if ($imgOutWidth -gt 0) {
+        $imgSizeFilter = Get-SizeFilter $imgSrcWidth $imgSrcHeight $imgOutWidth $imgOutHeight
+        $imgOutWidth  = $imgSizeFilter.Width
+        $imgOutHeight = $imgSizeFilter.Height
+    }
+
     $imgFfmpegArgs = @(
         '-y'
         '-loop', '1'
@@ -365,7 +409,7 @@ if (($supportedImageExts -contains $sourceExt) -and $AudioPath) {
     )
 
     if ($imgOutWidth -gt 0) {
-        $imgFfmpegArgs += @('-vf', ('scale={0}:{1}' -f $imgOutWidth, $imgOutHeight))
+        $imgFfmpegArgs += @('-vf', $imgSizeFilter.Filter)
     }
 
     $imgFfmpegArgs += $targetVideoEncodeArgs
@@ -391,9 +435,9 @@ if (($supportedImageExts -contains $sourceExt) -and $AudioPath) {
     Write-Host ('  FPS: {0}' -f $imgFPS)
     if ($imgOutWidth -gt 0) {
         if ($LTX) {
-            Write-Host ('  Size: {0}x{1} (LTX-2)' -f $imgOutWidth, $imgOutHeight)
+            Write-Host ('  Size: {0}x{1} (LTX-2){2}' -f $imgOutWidth, $imgOutHeight, $cropNote)
         } else {
-            Write-Host ('  Size: {0}x{1}' -f $imgOutWidth, $imgOutHeight)
+            Write-Host ('  Size: {0}x{1}{2}' -f $imgOutWidth, $imgOutHeight, $cropNote)
         }
     }
     Write-Host ('  CRF: {0}' -f $imgCRF)
@@ -542,6 +586,12 @@ if (Test-Path -LiteralPath $SourcePath -PathType Container) {
     if ($seqOutWidth % 2)  { $seqOutWidth++ }
     if ($seqOutHeight % 2) { $seqOutHeight++ }
 
+    if ($seqOutWidth -gt 0) {
+        $seqSizeFilter = Get-SizeFilter $seqSrcWidth $seqSrcHeight $seqOutWidth $seqOutHeight
+        $seqOutWidth  = $seqSizeFilter.Width
+        $seqOutHeight = $seqSizeFilter.Height
+    }
+
     $concatTempFile = [System.IO.Path]::GetTempFileName()
     try {
         $frameDuration = (1.0 / $seqFPS).ToString('0.######', [System.Globalization.CultureInfo]::InvariantCulture)
@@ -568,7 +618,7 @@ if (Test-Path -LiteralPath $SourcePath -PathType Container) {
         $seqFfmpegArgs += @('-r', $seqFPS.ToString('0.######', [System.Globalization.CultureInfo]::InvariantCulture))
 
         if ($seqOutWidth -gt 0) {
-            $seqFfmpegArgs += @('-vf', ('scale={0}:{1}' -f $seqOutWidth, $seqOutHeight))
+            $seqFfmpegArgs += @('-vf', $seqSizeFilter.Filter)
         }
 
         $seqFfmpegArgs += $targetVideoEncodeArgs
@@ -593,9 +643,9 @@ if (Test-Path -LiteralPath $SourcePath -PathType Container) {
         Write-Host ('  FPS: {0}' -f $seqFPS)
         if ($seqOutWidth -gt 0) {
             if ($LTX) {
-                Write-Host ('  Size: {0}x{1} (LTX-2)' -f $seqOutWidth, $seqOutHeight)
+                Write-Host ('  Size: {0}x{1} (LTX-2){2}' -f $seqOutWidth, $seqOutHeight, $cropNote)
             } else {
-                Write-Host ('  Size: {0}x{1}' -f $seqOutWidth, $seqOutHeight)
+                Write-Host ('  Size: {0}x{1}{2}' -f $seqOutWidth, $seqOutHeight, $cropNote)
             }
         }
         Write-Host ('  CRF: {0}' -f $seqCRF)
@@ -758,6 +808,12 @@ if ($LTX) {
     $scaleHeight = $best.H
 }
 
+if ($scaleWidth -gt 0) {
+    $sizeFilter  = Get-SizeFilter $sourceWidth $sourceHeight $scaleWidth $scaleHeight
+    $scaleWidth  = $sizeFilter.Width
+    $scaleHeight = $sizeFilter.Height
+}
+
 $ffprobeBitrateOutput = & ffprobe -v error -select_streams v:0 -show_entries stream=bit_rate -of default=noprint_wrappers=1:nokey=1 -- $SourcePath 2>&1
 $ffprobeExit = $LASTEXITCODE
 
@@ -882,9 +938,9 @@ if ($AudioPath -and $externalAudioCodec) {
 Write-Host ('  Frame range: {0} to {1} ({2} frames)' -f $StartFrame, $actualEndFrame, $frameCount)
 if ($scaleWidth -gt 0) {
     if ($LTX) {
-        Write-Host ('  Size: {0}x{1} (LTX-2)' -f $scaleWidth, $scaleHeight)
+        Write-Host ('  Size: {0}x{1} (LTX-2){2}' -f $scaleWidth, $scaleHeight, $cropNote)
     } else {
-        Write-Host ('  Size: {0}x{1}' -f $scaleWidth, $scaleHeight)
+        Write-Host ('  Size: {0}x{1}{2}' -f $scaleWidth, $scaleHeight, $cropNote)
     }
 }
 if ($FPS -gt 0) {
@@ -910,7 +966,7 @@ if ($StartFrame -gt 0 -or $actualEndFrame -lt $maxFrameIndex) {
     $filterParts = @('select=between(n\,{0}\,{1})' -f $StartFrame, $actualEndFrame)
     $filterParts += 'setpts=PTS-STARTPTS'
     if ($scaleWidth -gt 0) {
-        $filterParts += ('scale={0}:{1}' -f $scaleWidth, $scaleHeight)
+        $filterParts += $sizeFilter.Filter
     }
     if ($FPS -gt 0) {
         $filterParts += ('fps={0}' -f $FPS)
@@ -937,7 +993,7 @@ if ($StartFrame -gt 0 -or $actualEndFrame -lt $maxFrameIndex) {
 } elseif ($needsReencode) {
     $filterParts = @()
     if ($scaleWidth -gt 0) {
-        $filterParts += ('scale={0}:{1}' -f $scaleWidth, $scaleHeight)
+        $filterParts += $sizeFilter.Filter
     }
     if ($FPS -gt 0) {
         $filterParts += ('fps={0}' -f $FPS)