Fix -Frames negative range calculation to extract last N frames correctly (off-by-one error), add validation to reject invalid '-%' and '-0' formats with exit code 1, change '%' alone to extract single last frame instead of range, remove duplicate last frame from PNG sequence concat list, update Get-LastFrame.ps1 and Get-Frame.ps1 to clamp out-of-range frame indices instead of erroring and improve error messages with inline stderr output, add -y flag and -- separator to ffprobe calls, replace deprecated

Clone-Video.ps1

@@ -36,7 +36,7 @@
     - start-end: Extract frames from start to end (e.g., "100-200")
     - positive_number: Extract frames from 0 to that number (e.g., "50")
     - -negative_number: Extract last N frames (e.g., "-10")
-    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%", "-%")
+    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%")
     - all: Extract all frames (same as "0-%")
 .PARAMETER Sequence
     Path to PNG file for extracted frame. Can be absolute or relative to current directory. .png extension is added if not provided. If EndFrame is -1, extracts the last frame and excludes it from the cloned video. If EndFrame is not -1, extracts the frame at EndFrame index and excludes it from the cloned video.
@@ -228,6 +228,14 @@ if (-not [string]::IsNullOrWhiteSpace($Frames)) {
         Write-Error '-Frames cannot be used together with -StartFrame, -EndFrame, or -Sequence'
         exit 1
     }
+    if ($Frames -match '^-.*%') {
+        Write-Error "Invalid Frames format '$Frames': '-%' is not supported. Use '%' for the last frame, or -N for the last N frames."
+        exit 1
+    }
+    if ($Frames -match '^-0+$') {
+        Write-Error "Invalid Frames format '$Frames': a negative count must be at least 1. Use -1 for the last frame."
+        exit 1
+    }
 }
 
 $AudioPath = $null
@@ -478,13 +486,13 @@ if (Test-Path -LiteralPath $SourcePath -PathType Container) {
     $maxPngIndex = $pngFiles.Count - 1
 
     if (-not [string]::IsNullOrWhiteSpace($Frames)) {
-        $framesPattern = $Frames -replace '%', $maxPngIndex
+        $framesPattern = if ($Frames -eq '%') { "$maxPngIndex-$maxPngIndex" } else { $Frames -replace '%', $maxPngIndex }
         if ($framesPattern -ieq 'all') { $framesPattern = "0-$maxPngIndex" }
         if ($framesPattern -match '^(\d+)-(\d+)$') {
             $StartFrame = [int]$Matches[1]
             $EndFrame = [int]$Matches[2]
         } elseif ($framesPattern -match '^-(\d+)$') {
-            $StartFrame = [Math]::Max(0, $maxPngIndex - [int]$Matches[1])
+            $StartFrame = [Math]::Max(0, $maxPngIndex - [int]$Matches[1] + 1)
             $EndFrame = $maxPngIndex
         } elseif ($framesPattern -match '^\d+$') {
             $StartFrame = 0
@@ -601,7 +609,6 @@ if (Test-Path -LiteralPath $SourcePath -PathType Container) {
             $concatLines += "file '$pfPath'"
             $concatLines += "duration $frameDuration"
         }
-        $concatLines += "file '$($pngFiles[-1].FullName.Replace('\', '/'))'"
         [System.IO.File]::WriteAllLines($concatTempFile, $concatLines, [System.Text.UTF8Encoding]::new($false))
 
         $seqFfmpegArgs = @(
@@ -718,13 +725,13 @@ $totalFramesInt = [int]$totalFrames
 $maxFrameIndex = $totalFramesInt - 1
 
 if (-not [string]::IsNullOrWhiteSpace($Frames)) {
-    $framesPattern = $Frames -replace '%', $maxFrameIndex
+    $framesPattern = if ($Frames -eq '%') { "$maxFrameIndex-$maxFrameIndex" } else { $Frames -replace '%', $maxFrameIndex }
     if ($framesPattern -ieq 'all') { $framesPattern = "0-$maxFrameIndex" }
     if ($framesPattern -match '^(\d+)-(\d+)$') {
         $StartFrame = [int]$Matches[1]
         $EndFrame = [int]$Matches[2]
     } elseif ($framesPattern -match '^-(\d+)$') {
-        $StartFrame = [Math]::Max(0, $maxFrameIndex - [int]$Matches[1])
+        $StartFrame = [Math]::Max(0, $maxFrameIndex - [int]$Matches[1] + 1)
         $EndFrame = $maxFrameIndex
     } elseif ($framesPattern -match '^\d+$') {
         $StartFrame = 0

Create-Clip.ps1

@@ -11,7 +11,7 @@
     - start-end: Extract frames from start to end (e.g., "100-200")
     - positive_number: Extract frames from 0 to that number (e.g., "50")
     - -negative_number: Extract last N frames (e.g., "-10")
-    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%", "-%")
+    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%")
     - all: Extract all frames (same as "0-%")
 .PARAMETER Suffix
     Text inserted into the derived -Target name before the file extension. Defaults to "-Clip" and cannot be empty.

Create-Scenes.ps1

@@ -161,6 +161,7 @@ function Get-SceneList {
             Frames     = $end - $start + 1
             StartTime  = [Math]::Round($start / $Info.Fps, 3)
             EndTime    = [Math]::Round($end / $Info.Fps, 3)
+            TotalTime  = [Math]::Round(($end - $start + 1) / $Info.Fps, 3)
             Suffix     = Format-SceneSuffix -Template $Template -Number ($i + 1)
         }
     }

Get-Frame.ps1

@@ -1,13 +1,14 @@
 <#
 .SYNOPSIS
-    Extracts a specific frame of a video file to a PNG image using Get-LastFrame.ps1, requiring -Video and -Frame parameters from that script.
+    Extracts a specific frame of a video file to a PNG image. The extraction is done by Get-LastFrame.ps1, which this script calls with an image path derived from -Video and -Frame.
     The image filename used for the -Image parameter is automatically derived from the -Video filename, with a "-" followed by the "-Frame" value padded with zeros (at least 4 digits, wider numbers are not truncated) inserted before the image file extension (e.g., P01.mp4 for frame 10 becomes P01-0010.png).
 .PARAMETER Video
     Path to the input video file. Can be absolute or relative to current directory.
 .PARAMETER Frame
     0-based frame index to extract. Negative values count from the end:
-    -1 extracts the last frame (default), -2 extracts second-to-last, etc.
+    -1 extracts the last frame, -2 extracts second-to-last, etc.
-    The resulting frame index is clamped to the valid range (0 to total frames - 1).
+    The resulting frame index is clamped to the valid range (0 to total frames - 1): a positive value past the last frame
+    gives the last frame, and a negative value before the first frame gives frame 0.
 #>
 [CmdletBinding(SupportsShouldProcess)]
 param(
@@ -35,8 +36,7 @@ $totalFramesOutput = & ffprobe -v error -select_streams v:0 -count_frames -show_
 $ffprobeExit = $LASTEXITCODE
 
 if ($ffprobeExit -ne 0) {
-    $totalFramesOutput | ForEach-Object { Write-Error $_ }
+    Write-Error ('ffprobe failed to read video file: {0}{1}{2}' -f $VideoPath, [Environment]::NewLine, ($totalFramesOutput -join [Environment]::NewLine))
-    Write-Error ('ffprobe failed to read video file: {0}' -f $VideoPath)
     exit 1
 }
 
@@ -48,19 +48,15 @@ if (-not $totalFrames -or ([string]$totalFrames).Trim() -notmatch '^\d+$') {
 }
 
 $totalFramesInt = [int]([string]$totalFrames).Trim()
+if ($totalFramesInt -lt 1) {
+    Write-Error ('Video has no frames: {0}' -f $VideoPath)
+    exit 1
+}
 $maxFrameIndex = $totalFramesInt - 1
 
 # Resolve frame index (handles negative values that count from the end)
-$frameToExtract = if ($Frame -lt 0) {
+$requestedFrame = if ($Frame -lt 0) { $totalFramesInt + $Frame } else { $Frame }
-    $calculatedFrame = $totalFramesInt + $Frame
+$frameToExtract = [Math]::Max(0, [Math]::Min($requestedFrame, $maxFrameIndex))
-    [Math]::Max(0, [Math]::Min($calculatedFrame, $maxFrameIndex))
-} else {
-    if ($Frame -gt $maxFrameIndex) {
-        Write-Error ('Frame index {0} is out of range. Valid range: 0 to {1}' -f $Frame, $maxFrameIndex)
-        exit 1
-    }
-    $Frame
-}
 
 # Derive the output image path: insert "-XXXX" (zero-padded resolved frame index) before .png extension
 $videoBase = [System.IO.Path]::GetFileNameWithoutExtension($VideoPath)

Get-FramesRange.ps1

@@ -11,7 +11,7 @@
     - start-end: Extract frames from start to end (e.g., "100-200")
     - positive_number: Extract frames from 0 to that number (e.g., "50")
     - -negative_number: Extract last N frames (e.g., "-10")
-    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%", "-%")
+    - %: Represents the last frame index. Can be used alone or in ranges (e.g., "%", "10-%")
     - all: Extract all frames (same as "0-%")
 .DESCRIPTION
     Extracts specific range of frames of a video file to PNG images using ffmpeg.
@@ -40,6 +40,15 @@ if (-not (Test-Path -LiteralPath $VideoPath)) {
     exit 1
 }
 
+if ($Frames -match '^-.*%') {
+    Write-Error "Invalid Frames format '$Frames': '-%' is not supported. Use '%' for the last frame, or -N for the last N frames."
+    exit 1
+}
+if ($Frames -match '^-0+$') {
+    Write-Error "Invalid Frames format '$Frames': a negative count must be at least 1. Use -1 for the last frame."
+    exit 1
+}
+
 $PSNativeCommandUseErrorActionPreference = $false
 
 $totalFramesOutput = & ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -of csv=p=0 -- $VideoPath 2>&1
@@ -65,7 +74,7 @@ $startFrame = 0
 $endFrame = 0
 
 # Replace % with actual last frame index, and handle 'all' keyword
-$framesPattern = $Frames -replace '%', $maxFrameIndex
+$framesPattern = if ($Frames -eq '%') { "$maxFrameIndex-$maxFrameIndex" } else { $Frames -replace '%', $maxFrameIndex }
 if ($framesPattern -ieq 'all') {
     $framesPattern = "0-$maxFrameIndex"
 }
@@ -76,7 +85,7 @@ if ($framesPattern -match '^(\d+)-(\d+)$') {
 }
 elseif ($framesPattern -match '^-(\d+)$') {
     $negativeCount = [int]$matches[1]
-    $startFrame = [Math]::Max(0, $maxFrameIndex - $negativeCount)
+    $startFrame = [Math]::Max(0, $maxFrameIndex - $negativeCount + 1)
     $endFrame = $maxFrameIndex
 }
 elseif ($framesPattern -match '^\d+$') {

Get-LastFrame.ps1

@@ -12,7 +12,8 @@
 .PARAMETER Frame
     0-based frame index to extract. Negative values count from the end:
     -1 extracts the last frame (default), -2 extracts second-to-last, etc.
-    The resulting frame index is clamped to the valid range (0 to total frames - 1).
+    The resulting frame index is clamped to the valid range (0 to total frames - 1): a positive value past the last frame
+    gives the last frame, and a negative value before the first frame gives frame 0.
 .DESCRIPTION
     Extracts a specific frame of a video file to a PNG image using ffmpeg.
     Supports negative frame indices to count from the end of the video.
@@ -36,14 +37,14 @@ $ErrorActionPreference = 'Stop'
 
 $VideoPath = $Video
 
-if (-not (Test-Path $VideoPath)) {
+if (-not (Test-Path -LiteralPath $VideoPath)) {
     Write-Error ('Video file not found: {0}' -f $VideoPath)
     exit 1
 }
 
 $PSNativeCommandUseErrorActionPreference = $false
 
-$totalFrames = & ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -of csv=p=0 $VideoPath 2>&1 | Select-Object -First 1
+$totalFrames = & ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -of csv=p=0 -- $VideoPath 2>&1 | Select-Object -First 1
 
 if (-not $totalFrames -or $totalFrames -notmatch '^\d+$') {
     Write-Error ('Could not determine frame count for: {0}' -f $VideoPath)
@@ -51,21 +52,15 @@ if (-not $totalFrames -or $totalFrames -notmatch '^\d+$') {
 }
 
 $totalFramesInt = [int]$totalFrames
-$maxFrameIndex = $totalFramesInt - 1
+if ($totalFramesInt -lt 1) {
-
+    Write-Error ('Video has no frames: {0}' -f $VideoPath)
-$frameToExtract = if ($Frame -lt 0) {
-    # Negative values count from the end
-    $calculatedFrame = $totalFramesInt + $Frame
-    # Clamp to valid range [0, maxFrameIndex]
-    [Math]::Max(0, [Math]::Min($calculatedFrame, $maxFrameIndex))
-} else {
-    # Positive values are direct indices
-    if ($Frame -gt $maxFrameIndex) {
-        Write-Error ('Frame index {0} is out of range. Valid range: 0 to {1}' -f $Frame, $maxFrameIndex)
     exit 1
 }
-    $Frame
+$maxFrameIndex = $totalFramesInt - 1
-}
+
+# Negative values count from the end; the result is clamped to [0, maxFrameIndex]
+$requestedFrame = if ($Frame -lt 0) { $totalFramesInt + $Frame } else { $Frame }
+$frameToExtract = [Math]::Max(0, [Math]::Min($requestedFrame, $maxFrameIndex))
 
 Write-Host ('Total frames: {0} - extracting frame index {1}' -f $totalFramesInt, $frameToExtract)
 
@@ -98,7 +93,7 @@ if ($PSCmdlet.ShouldProcess($ImagePath, ('Extract frame {0} to PNG' -f $frameToE
         '-y'
         '-i', $VideoPath
         '-vf', $videoFilter
-        '-vsync', 'vfr'
+        '-fps_mode', 'vfr'
         '-frames:v', '1'
         '-q:v', '1'
         '--', $ImagePath
@@ -107,8 +102,12 @@ if ($PSCmdlet.ShouldProcess($ImagePath, ('Extract frame {0} to PNG' -f $frameToE
     $ffmpegStderr = & ffmpeg @ffmpegArgs 2>&1
 
     if ($LASTEXITCODE -ne 0) {
-        $ffmpegStderr | ForEach-Object { Write-Error $_ }
+        Write-Error ('ffmpeg failed to extract frame {0}: {1}' -f $frameToExtract, (($ffmpegStderr | Out-String).Trim()))
-        Write-Error 'ffmpeg failed to extract the last frame.'
+        exit 1
+    }
+
+    if (-not (Test-Path -LiteralPath $ImagePath)) {
+        Write-Error ('ffmpeg reported success but no image was written for frame {0}: {1}' -f $frameToExtract, $ImagePath)
         exit 1
     }
 

skill/Clone-Video.md

@@ -45,8 +45,9 @@ The output container is chosen from the `-Target` extension (`.mp4`, `.webm`, or
 - **`-Frames`** (optional): 0-based frame range to clone. Mutually exclusive with `-StartFrame`, `-EndFrame`, and `-Sequence`. Supported formats:
     - `start-end`: Clone frames from `start` to `end` (e.g., `"100-500"`)
     - `positive_number`: Clone frames from 0 to that number (e.g., `"50"`)
-    - `-N`: Clone last N frames (e.g., `"-10"`)
+    - `-N`: Clone the last N frames (e.g., `"-10"` clones frames 90 to 99 of a 100-frame video; `"-1"` clones the last frame only)
-    - `%`: Represents the last frame index; can be used alone or in ranges (e.g., `"%"`, `"10-%"`, `"-%"`)
+    - `%`: The last frame index. Alone (`"%"`) it selects only the last frame. In a range (e.g., `"10-%"`) it is the end of the range
+    - `-%` is not supported and is rejected with exit code `1`
     - `all`: Clone all frames (same as `"0-%"`)
 - **`-Sequence`** (optional): Path to PNG file for extracted frame (`.png` extension added if missing)
 - **`-Size`** (optional): Size of the output video. Uses the input video's size if not specified. Possible values: `320p`, `384p`, `480p`, `720p`, `900p`, `1080p`, `HD`, `1440p`, `2K`, `2160p`, `4K`, or custom size in format `width:height`. For standard named sizes the output **preserves the source aspect ratio**: the reference height is used as the short-side target and the other dimension is computed from the source AR — landscape/square sources use the reference as the output height (width computed), portrait sources use it as the output width (height computed). Custom sizes (`width:height`) are applied exactly as given. Forces a video re-encode, since scaling requires re-encoding.

skill/Create-Clip.md

@@ -10,8 +10,9 @@ Sources carrying a `.skip` marker keep that marker last: `P01.skip.mp4` becomes
 - **`-Frames`** (required): 0-based frame range to clip. Supported formats:
     - `start-end`: Clip frames from `start` to `end` (e.g., `"100-200"`)
     - `positive_number`: Clip frames from 0 to that number (e.g., `"50"`)
-    - `-N`: Clip last N frames (e.g., `"-10"`)
+    - `-N`: Clip the last N frames (e.g., `"-10"` clips frames 90 to 99 of a 100-frame video; `"-1"` clips the last frame only)
-    - `%`: Represents the last frame index; can be used alone or in ranges (e.g., `"%"`, `"10-%"`, `"-%"`)
+    - `%`: The last frame index. Alone (`"%"`) it selects only the last frame. In a range (e.g., `"10-%"`) it is the end of the range
+    - `-%` is not supported and is rejected with exit code `1`
     - `all`: Clip all frames (same as `"0-%"`)
 - **`-Suffix`** (optional): Text inserted into the derived target name before the file extension. Defaults to `-Clip`, so `P01.mp4` becomes `P01-Clip.mp4`. Include any separator you want, such as the leading `-`. Must not be empty, because an empty suffix would produce a target with the same name as the source. For example, `-Suffix "-Clip-Shot-1"` turns `P01.mp4` into `P01-Clip-Shot-1.mp4`.
 - **Extra parameters**: Any additional parameters accepted by `Clone-Video.ps1` (e.g. `-Size`, `-FPS`, `-NoAudio`, `-Audio`, `-CRF`, `-Metadata`, `-Reverse`, `-LTX`) are forwarded directly. The parameters `-Video`, `-Frames`, `-Suffix` and `-Target` are handled by this script and must not be repeated.

skill/Create-Scenes.md

@@ -31,14 +31,14 @@ Refer to [Clone-Video.ps1](Clone-Video.md) for a full description of the encodin
 Example scene list for a video with two hard cuts at frames 30 and 60:
 
 ```text
-Index StartFrame EndFrame Frames StartTime EndTime Suffix
+Index StartFrame EndFrame Frames StartTime EndTime TotalTime Suffix
------ ---------- -------- ------ --------- ------- ------
+----- ---------- -------- ------ --------- ------- --------- ------
-    1          0       29     30      0.00    0.97 -Scene-01
+    1          0       29     30      0.00    0.97      1.00 -Scene-01
-    2         30       59     30      1.00    1.97 -Scene-02
+    2         30       59     30      1.00    1.97      1.00 -Scene-02
-    3         60       89     30      2.00    2.97 -Scene-03
+    3         60       89     30      2.00    2.97      1.00 -Scene-03
 ```
 
-`StartTime` and `EndTime` are in seconds, computed as frame index divided by frame rate.
+`StartTime` and `EndTime` are in seconds, computed as frame index divided by frame rate. `EndTime` is the time of the last frame of the scene, so it is one frame before the next scene starts. `TotalTime` is the scene's duration in seconds: `Frames` divided by frame rate.
 
 ## Scene Threshold
 

skill/Get-Frame.md

@@ -8,7 +8,7 @@ Extracts a specific frame of a video file to a PNG image by calling [Get-LastFra
 - **`-Frame`** (required): 0-based frame index to extract.
     - Positive values: Direct frame index (e.g., `0` = first frame, `100` = frame 100)
     - Negative values: Count from the end (e.g., `-1` = last frame, `-2` = second-to-last)
-    - Values are automatically clamped to the valid range (0 to total frames − 1)
+    - Values are automatically clamped to the valid range (0 to total frames − 1): a positive value past the last frame gives the last frame, and a negative value before the first frame gives frame 0
 
 ## Image Filename Derivation
 

skill/Get-FramesRange.md

@@ -12,11 +12,11 @@ Extracts a specific range of frames from a video file to PNG images.
 
 - **`start-end`**: Extract frames from start to end index (e.g., `100-200`)
 - **`positive_number`**: Extract frames from 0 to that number (e.g., `50` extracts frames 0-50)
-- **`-negative_number`**: Extract last N frames (e.g., `-10` extracts last 10 frames)
+- **`-negative_number`**: Extract the last N frames (e.g., `-10` extracts frames 90 to 99 of a 100-frame video; `-1` extracts the last frame only)
-- **`%`**: Represents the last frame index. Can be used alone or in ranges:
+- **`%`**: The last frame index. Alone (`%`) it extracts only the last frame. In a range it is the end of the range:
     - `%` - Extract only the last frame
     - `10-%` - Extract from frame 10 to the last frame
-    - `-%` - Extract only the first frame (frame 0)
+- `-%` is not supported and is rejected with exit code `1`
 - **`all`**: Extract all frames (same as `0-%`)
 
 ## Examples
@@ -24,63 +24,56 @@ Extracts a specific range of frames from a video file to PNG images.
 **Extract specific range:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "100-200"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "100-200"
 # Creates: Frames/video_0100.png, Frames/video_0101.png, ..., Frames/video_0200.png
 ```
 
 **Extract first 50 frames:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "50"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "50"
 # Creates: Frames/video_0000.png through Frames/video_0050.png
 ```
 
 **Extract last 10 frames:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "-10"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "-10"
 # If video has 500 frames, creates: Frames/video_0490.png through Frames/video_0499.png
 ```
 
 **Extract only the last frame:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "%"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "%"
 # If video has 500 frames, creates: Frames/video_0499.png
 ```
 
 **Extract from frame 10 to the last frame:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "10-%"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "10-%"
 # If video has 500 frames, creates: Frames/video_0010.png through Frames/video_0499.png
 ```
 
-**Extract only the first frame:**
-
-```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "-%"
-# Creates: Frames/video_0000.png
-```
-
 **Extract all frames:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "all"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "all"
 # If video has 500 frames, creates: Frames/video_0000.png through Frames/video_0499.png
 ```
 
 **Custom output pattern:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "0-100" -Images "output_frame"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "0-100" -Images "output_frame"
 # Creates: output_frame_0000.png through output_frame_0100.png
 ```
 
 **Full output path:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "50-150" -Images "C:\Output\frame_%04d.png"
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "50-150" -Images "C:\Output\frame_%04d.png"
 ```
 
 **Note:** Frame numbers in output filenames reflect the actual video frame index (0-based).
@@ -99,11 +92,11 @@ This script supports `-WhatIf` and `-Confirm` for safe execution:
 **Simulate without extracting:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "100-200" -WhatIf
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "100-200" -WhatIf
 ```
 
 **Prompt before each frame:**
 
 ```powershell
-.\Get-Frames.ps1 -Video video.mp4 -Frames "0-10" -Confirm
+.\Get-FramesRange.ps1 -Video video.mp4 -Frames "0-10" -Confirm
 ```

skill/Get-LastFrame.md

@@ -9,7 +9,7 @@ Extracts a specific frame of a video file to a PNG image.
 - **`-Frame`** (optional): 0-based frame index to extract (default: -1)
     - Positive values: Direct frame index (e.g., 0 = first frame, 100 = frame 100)
     - Negative values: Count from the end (e.g., -1 = last frame, -2 = second-to-last)
-    - Values are automatically clamped to valid range (0 to total frames - 1)
+    - Values are automatically clamped to valid range (0 to total frames - 1): a positive value past the last frame gives the last frame, and a negative value before the first frame gives frame 0
 
 ## Filename Pattern
 

skill/SKILL.md

@@ -11,7 +11,7 @@ The per-script pages sit in the same folder as this file. Load a page only when
 
 ## Prerequisites
 
-- **Platform**: Windows 11 only. The scripts are tested on Windows 11 and nowhere else. Linux and WSL are not supported. Run them with Windows PowerShell 7 (`pwsh.exe`).
+- **Platform**: Windows 11 only. The scripts are tested on Windows 11 and nowhere else. Linux and WSL are not supported. Run them with PowerShell 7 for Windows (`pwsh.exe`).
 - **PowerShell 7+** (`pwsh`). Required by every script.
 - **Core tools**: **ffmpeg** and **ffprobe** on `PATH`. Most scripts need both. [Stitch-InBetween.ps1](Stitch-InBetween.md) needs only ffmpeg. [Get-FramesCount.ps1](Get-FramesCount.md), [Get-VideoInfo.ps1](Get-VideoInfo.md) and [Create-FullSubtitle.ps1](Create-FullSubtitle.md) need only ffprobe.
 - **Optional tools**, needed only by specific scripts:
@@ -49,7 +49,7 @@ If a core check fails, or a check needed by the current task fails, **stop**. Te
 
 - Git: `git clone https://git.gurusushi.dyndns.org/guru/Video-Processing-Scripts.git` (repository `guru/Video-Processing-Scripts`).
 - SVN: `public-svn`, project `Video Processing Scripts`.
-- The script folder must be on `PATH` so scripts can be called from any directory.
+- The script folder should be on `PATH` so that `Get-Command` finds the scripts and the `.cmd` wrappers work. This does not make `pwsh -File <bare name>` work. See [How to Run the Scripts](#how-to-run-the-scripts).
 - `Update-Video-Processing-Scripts.cmd` updates a Git copy to the latest version. Run it only with the user's approval.
 
 ## How to Run the Scripts
@@ -64,6 +64,12 @@ If a core check fails, or a check needed by the current task fails, **stop**. Te
 pwsh -NoProfile -File .\Create-Clip.ps1 -Video "My Video.mp4" -Frames "100-200"
 ```
 
+From any other folder, use the full script path and an absolute video path:
+
+```powershell
+pwsh -NoProfile -File "C:\path\to\Video Processing Scripts\Create-Clip.ps1" -Video "D:\clips\P01.mp4" -Frames "100-200"
+```
+
 ## Conventions
 
 - Frame indices are **0-based**: the first frame is `0`.
@@ -73,18 +79,19 @@ pwsh -NoProfile -File .\Create-Clip.ps1 -Video "My Video.mp4" -Frames "100-200"
     | --- | --- |
     | `start-end` | Frames from `start` to `end`, e.g. `100-200` |
     | `N` | Frames 0 to `N`, not only frame `N` |
-    | `-N` | The last `N` frames |
+    | `-N` | The last `N` frames. `-1` is the last frame. |
-    | `%` | The last frame index, alone or in a range, e.g. `10-%` |
+    | `%` | The last frame index. Alone it selects only the last frame. In a range, e.g. `10-%`, it is the end of the range. |
+    | `-%` | Not supported. Rejected with exit code `1`. |
     | `all` | All frames, same as `0-%` |
 
-- **`-Frame` syntax** for [Get-Frame.ps1](Get-Frame.md) and [Get-LastFrame.ps1](Get-LastFrame.md): a single frame index. Negative values count from the end (`-1` is the last frame). Out-of-range values are clamped.
+- [Create-Scenes.ps1](Create-Scenes.md) takes no frame range. It finds scene boundaries itself.
+- **`-Frame` syntax** for [Get-Frame.ps1](Get-Frame.md) and [Get-LastFrame.ps1](Get-LastFrame.md): a single frame index. Negative values count from the end (`-1` is the last frame). [Get-Frame.ps1](Get-Frame.md) clamps values to the valid range: a positive value past the last frame gives the last frame, and a negative value before the first frame gives frame 0. [Get-LastFrame.ps1](Get-LastFrame.md) clamps the same way.
 - If the extension is omitted, `.mp4`, `.webm` and `.mkv` are tried in that order by [Clone-Video.ps1](Clone-Video.md), [Create-Clip.ps1](Create-Clip.md) and [Create-Scenes.ps1](Create-Scenes.md).
 - **`.skip` marker**: a file named `<name>.skip.<ext>` is excluded from batch processing, and the marker stays last in derived names.
     - [Create-Clip.ps1](Create-Clip.md) accepts `.mp4`, `.webm` and `.mkv`, case-insensitive. `P01.skip.mp4` gives `P01-Clip.skip.mp4`.
     - [Crop-Clips.ps1](Crop-Clips.md) processes only `.mp4` files and skips `*.skip.mp4` and `*.bak.mp4`.
     - [Create-Scenes.ps1](Create-Scenes.md) gives `P01-Scene-01.skip.mp4` for `P01.skip.mp4`.
-- Batch operations skip `.bak.mp4` backup files.
+- On failure, scripts exit with `1`, print an error message to the error stream, and create no files. Check `$LASTEXITCODE` after each call.
-- Scripts exit with `0` on success and `1` on failure. Check `$LASTEXITCODE` after each call.
 - **Forwarded parameters**: [Create-Clip.ps1](Create-Clip.md) and [Create-Scenes.ps1](Create-Scenes.md) accept the extra parameters of [Clone-Video.ps1](Clone-Video.md) and forward them, for example `-Size`, `-FPS`, `-NoAudio`, `-Audio`, `-CRF`, `-Metadata`, `-Reverse` and `-LTX`. Each reserves `-Video`, `-Frames`, `-Suffix` and `-Target` for itself, so do not repeat them in the extra parameters.
 
 ## Safety Rules
@@ -102,7 +109,7 @@ pwsh -NoProfile -File .\Create-Clip.ps1 -Video "My Video.mp4" -Frames "100-200"
     | [Create-Clip.ps1](Create-Clip.md) | An existing derived clip is replaced without a prompt. The clip is written by Clone-Video.ps1, with the `.skip` marker kept last in the name. |
     | [Create-FullSubtitle.ps1](Create-FullSubtitle.md) | Overwrites `-Output` without a prompt. |
     | [Create-PillarBox.ps1](Create-PillarBox.md) | An existing `-Target` video is replaced without a prompt. If ffmpeg fails, the target is removed, including a file that existed before the run. |
-    | [Create-Scenes.ps1](Create-Scenes.md) | Only when `-List` is not given. Deletes earlier clips of the same source in the source folder, then creates the new ones, which replace the old ones. |
+    | [Create-Scenes.ps1](Create-Scenes.md) | Without `-List`, deletes the earlier scene clips of the same source in the source folder, then creates the new ones. `-List` creates and deletes nothing. |
     | [Create-ShortClip.ps1](Create-ShortClip.md) | Overwrites the output video. With the default `-Images` and without `-Render`, clears the `Frames` folder. With explicit `-Images`, deletes only matching frames. Removes its temporary folders, and the `Frames` folder unless `-Keep` is given. |
     | [Create-Turnaround.ps1](Create-Turnaround.md) | An existing `-Target` image is replaced without a prompt. The folder of `-Target` must exist. |
     | [Crop-Clips.ps1](Crop-Clips.md) | Works in place when `-Source` and `-Target` are omitted or equal. See the in-place rule below. |
@@ -114,8 +121,8 @@ pwsh -NoProfile -File .\Create-Clip.ps1 -Video "My Video.mp4" -Frames "100-200"
     | [Get-VideoInfo.ps1](Get-VideoInfo.md) | Reads only. Creates and deletes nothing. |
     | [Stitch-InBetween.ps1](Stitch-InBetween.md) | Deletes an existing `-Video` before generating. Deletes everything inside an existing `-TempDir`. |
 
-- **Crop-Clips in-place rule.** Crop-Clips works on the current folder when `-Source` and `-Target` are omitted, and it backs up each file it crops to `<name>.bak.mp4`, replacing any existing backup without a prompt. Skipped files are not backed up and keep their backup. A re-run with a different `-Size` crops the already cropped files again, so the backup then holds the previous cropped output and the true original is lost. So:
+- **Crop-Clips in-place rule.** Crop-Clips works on the current folder when `-Source` and `-Target` are omitted or equal, and it backs up each file it crops to `<name>.bak.mp4`, replacing any existing backup without a prompt. Skipped files are not backed up and keep their backup. A re-run with a different `-Size` crops the already cropped files again, so the backup then holds the previous cropped output and the true original is lost. So:
-    - Always pass explicit `-Source` and `-Target`, and prefer a separate `-Target` folder.
+    - Always pass explicit `-Source` and `-Target`, and prefer a separate `-Target` folder. Never pass the same folder for both.
     - Use in-place mode only when the user asks for it.
     - Warn the user before re-running in place with a different `-Size` on files that already have a `.bak.mp4`.
     - Never delete `.bak.mp4` files yourself unless the user asks.