Add support for silver, gray, charcoal, and custom hex color pillarbox effects with color:RRGGBB syntax

Create-PillarBox.ps1

@@ -9,8 +9,12 @@
     saved alongside the source (e.g. video.mp4 + -Effect black -> video-black.mp4).
 .PARAMETER Effect
     The effect to apply to the side bars. Possible values are:
-    black: The side bars will be black.
-    white: The side bars will be white.
+    black: The side bars will be solid black (#000000).
+    white: The side bars will be solid white (#FFFFFF).
+    silver: The side bars will be solid silver (#C0C0C0), a light neutral gray.
+    gray: The side bars will be solid mid gray (#808080).
+    charcoal: The side bars will be solid charcoal (#36454F), a very dark blue-gray.
+    color:RRGGBB: The side bars will be filled with the given hex color (case-insensitive). Example: -Effect color:FFFF00 yields yellow bars.
     standard: Creates softly blurred side bars generated from the video itself, with a subtle zoom to fill the 16:9 frame.
     dark: Produces blurred side bars with reduced brightness, creating a darker, more contrasted background that enhances focus on the main video.
     gaussian: Generates smooth, high‑quality Gaussian‑blurred side bars for a clean, professional broadcast-style background.
@@ -186,10 +190,30 @@ function Resolve-Size {
 }
 
 # Validate -Effect first so it can be used in the default -Target name.
-$validEffects = @('black', 'white', 'standard', 'dark', 'gaussian')
+# Solid-color effects map an effect name to the ffmpeg color string used in the pad filter.
+# Named SVG colors (black, white, silver, gray) are passed through directly; custom shades
+# (e.g. charcoal) use an explicit 0xRRGGBB value since ffmpeg does not recognise the name.
+$solidColorMap = @{
+    'black'    = 'black'
+    'white'    = 'white'
+    'silver'   = 'silver'
+    'gray'     = 'gray'
+    'charcoal' = '0x36454F'
+}
+$blurEffects = @('standard', 'dark', 'gaussian')
+$validEffects = @($solidColorMap.Keys) + $blurEffects
 $effectLower = $Effect.ToLower()
-if ($effectLower -notin $validEffects) {
-    throw "Invalid -Effect value: $Effect. Must be one of: $($validEffects -join ', ')"
+
+# Ad-hoc solid color via 'color:RRGGBB' syntax (case-insensitive on the hex value).
+# The hex string is normalised to lowercase and the effect is treated like the
+# built-in solid-color effects (simple pad filter, no blur).
+$customColorHex = $null
+if ($effectLower -match '^color:([0-9a-f]{6})$') {
+    $customColorHex = $Matches[1]
+    $effectLower = "color:$customColorHex"
+}
+elseif ($effectLower -notin $validEffects) {
+    throw "Invalid -Effect value: $Effect. Must be one of: $($validEffects -join ', '), or 'color:RRGGBB' (6 hex digits)."
 }
 
 # Append .mp4 extension if missing on -Source
@@ -205,10 +229,13 @@ $sourceFull = (Resolve-Path -LiteralPath $Source).Path
 
 # Default -Target: same directory and base name as -Source, with the effect appended
 # (e.g. C:\clips\video.mp4 + -Effect Black -> C:\clips\video-black.mp4).
+# For 'color:RRGGBB', the colon is replaced with a dash to keep the filename valid
+# (e.g. -Effect color:FFFF00 -> video-color-ffff00.mp4).
 if ([string]::IsNullOrWhiteSpace($Target)) {
     $srcDir = [System.IO.Path]::GetDirectoryName($sourceFull)
     $srcBase = [System.IO.Path]::GetFileNameWithoutExtension($sourceFull)
-    $Target = Join-Path $srcDir "$srcBase-$effectLower.mp4"
+    $effectForName = $effectLower -replace ':', '-'
+    $Target = Join-Path $srcDir "$srcBase-$effectForName.mp4"
 }
 elseif (-not [System.IO.Path]::GetExtension($Target)) {
     $Target = "$Target.mp4"
@@ -256,14 +283,21 @@ if ($outHeight % 2) { $outHeight++ }
 $scaleFg = "scale=w=${outWidth}:h=${outHeight}:force_original_aspect_ratio=decrease"
 
 # Build the video filter graph depending on the requested -Effect.
-#   black/white   : simple pad with the solid color (uses -vf)
+#   solid colors  : simple pad with the chosen color (uses -vf)
+#                   black, white, silver, gray, charcoal, color:RRGGBB
 #   standard      : softly blurred background with a subtle zoom (uses -filter_complex)
 #   dark          : blurred background with reduced brightness/saturation (uses -filter_complex)
 #   gaussian      : high-quality Gaussian-blurred background (uses -filter_complex)
-$useFilterComplex = $effectLower -in @('standard', 'dark', 'gaussian')
+$useFilterComplex = $effectLower -in $blurEffects
 
 if (-not $useFilterComplex) {
-    $padExpr = "pad=${outWidth}:${outHeight}:(ow-iw)/2:(oh-ih)/2:${effectLower}"
+    if ($customColorHex) {
+        $padColor = "0x$customColorHex"
+    }
+    else {
+        $padColor = $solidColorMap[$effectLower]
+    }
+    $padExpr = "pad=${outWidth}:${outHeight}:(ow-iw)/2:(oh-ih)/2:${padColor}"
     $vf = "${scaleFg},${padExpr},setsar=1"
 }
 else {