Add WebM/MKV support with automatic transcoding to H.264/AAC for MP4 compatibility

Create-PillarBox.ps1

@@ -158,24 +158,28 @@ function Resolve-Size {
         throw "Invalid -Size value: $Value. Use a named preset (480p, 720p, 1080p, HD, 1440p, 2K, 2160p, 4K) or 'width:height'."
     }
 
-    # Compute the minimum 16:9 frame that fully contains the source
-    $minWidthFromHeight = [int][math]::Ceiling($SourceHeight * 16.0 / 9.0)
-    $minHeightFromWidth = [int][math]::Ceiling($SourceWidth * 9.0 / 16.0)
+    # Pick the smallest standard 16:9 preset whose longer side (width) is at least
+    # the source's longer side. The foreground is scaled down with
+    # 'force_original_aspect_ratio=decrease', so the source is allowed to shrink
+    # to fit; we only need the preset to be "big enough" relative to the source's
+    # largest dimension. This produces the documented behavior:
+    #   1080x1920 portrait  -> 1920x1080 (vertical bars on either side)
+    #   720x1280  portrait  -> 1280x720
+    #   2560x1080 landscape -> 2560x1440 (horizontal bars top/bottom)
+    $longSide = [math]::Max($SourceWidth, $SourceHeight)
 
-    $neededWidth = [math]::Max($SourceWidth, $minWidthFromHeight)
-    $neededHeight = [math]::Max($SourceHeight, $minHeightFromWidth)
-
-    # Pick the smallest standard 16:9 size that contains the source
     $unique = $standards | Sort-Object { $_.Width } -Unique
     foreach ($s in $unique) {
-        if ($s.Width -ge $neededWidth -and $s.Height -ge $neededHeight) {
+        if ($s.Width -ge $longSide) {
             return [pscustomobject]@{ Width = $s.Width; Height = $s.Height }
         }
     }
 
-    # Source larger than any standard preset: use exact computed dimensions (rounded to even)
-    $w = $neededWidth + ($neededWidth % 2)
-    $h = $neededHeight + ($neededHeight % 2)
+    # Source larger than any standard preset: build a 16:9 frame whose width
+    # matches the source's longer side (rounded to even).
+    $w = $longSide + ($longSide % 2)
+    $h = [int][math]::Ceiling($w * 9.0 / 16.0)
+    if ($h % 2) { $h++ }
     return [pscustomobject]@{ Width = $w; Height = $h }
 }
 
@@ -349,7 +353,11 @@ if ($PSCmdlet.ShouldProcess($targetFull, 'Create pillar-boxed video with ffmpeg'
             Remove-Item -LiteralPath $targetFull -Force -ErrorAction SilentlyContinue
         }
 
-        $ffmpegOutput | ForEach-Object { Write-Error $_ }
+        # Use Write-Host (not Write-Error) so the full ffmpeg output is shown;
+        # under $ErrorActionPreference = 'Stop' a piped Write-Error would terminate
+        # on the first line, swallowing the rest of the diagnostic output and the
+        # final 'throw' below.
+        $ffmpegOutput | ForEach-Object { Write-Host $_ }
         Write-Host "ffmpeg $($ffArgs -join ' ')"
         throw "ffmpeg failed while creating pillar-boxed video: $($inInfo.FileName)"
     }