Video-Processing-Scripts/skill/Get-LastFrame.md

Get-LastFrame.ps1

Extracts a specific frame of a video file to a PNG image.

Parameters

• -Video (required): Path to input video file
• -Image (required): Path to output PNG image file. Supports a printf-style numbering token like Get-FramesRange.ps1 — see Filename Pattern. The output directory is created when it does not exist.
• -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)

Filename Pattern

-Image may contain a printf-style numbering token, which is replaced with the actual 0-based frame index that was extracted — after -Frame has been resolved, so negative indices produce the real frame number:

Token	Meaning	Frame 99	Frame 7
%d	No padding	99	7
%04d	Zero-padded to 4 digits	0099	0007
%06d	Zero-padded to 6 digits	000099	000007

A path without a token is used literally, so existing commands such as -Image last_frame.png are unaffected (only one frame is produced, so no numbering is needed).

.\Get-LastFrame.ps1 -Video video.mp4 -Image "frame_%04d.png"
# 100-frame video -> frame_0099.png

When the pattern resolves, the script reports the final name:

Total frames: 100 - extracting frame index 99
Output pattern resolved to: frame_0099.png
Frame saved to: frame_0099.png

Note: the token is expanded by the script, not by ffmpeg. ffmpeg would treat %04d in an output path as an image-sequence counter starting at 1 (writing frame_0001.png regardless of which frame was selected); expanding it here guarantees the number is the real video frame index, matching Get-FramesRange.ps1.

Examples

Extract last frame:

.\Get-LastFrame.ps1 -Video video.mp4 -Image last_frame.png

Extract specific frame:

.\Get-LastFrame.ps1 -Video video.mp4 -Image frame_100.png -Frame 100

Extract first frame:

.\Get-LastFrame.ps1 -Video video.mp4 -Image first_frame.png -Frame 0

Extract second-to-last frame:

.\Get-LastFrame.ps1 -Video video.mp4 -Image second_last.png -Frame -2

Extract 10th frame from the end:

.\Get-LastFrame.ps1 -Video video.mp4 -Image frame_minus_10.png -Frame -10

Using absolute paths:

.\Get-LastFrame.ps1 -Video "C:\Videos\input.mp4" -Image "C:\Frames\output.png" -Frame 50

Filename pattern with the frame number:

.\Get-LastFrame.ps1 -Video video.mp4 -Image "frame_%04d.png"
# If video has 100 frames, creates: frame_0099.png

Full output path with a pattern (directory is created if missing):

.\Get-LastFrame.ps1 -Video video.mp4 -Image "C:\Output\frame_%04d.png" -Frame 50
# Creates: C:\Output\frame_0050.png

Pattern with a negative frame index:

.\Get-LastFrame.ps1 -Video video.mp4 -Image "p_%06d.png" -Frame -2
# If video has 100 frames, creates: p_000098.png

Pattern without padding:

.\Get-LastFrame.ps1 -Video video.mp4 -Image "f_%d.png" -Frame 7
# Creates: f_7.png

Safe Execution

This script supports -WhatIf and -Confirm for safe execution:

• -WhatIf: Simulate the operation without actually extracting the frame. Shows the resolved output name and what would be extracted; no output directory is created.
• -Confirm: Prompt for confirmation before extracting the frame.

Simulate without extracting:

.\Get-LastFrame.ps1 -Video video.mp4 -Image frame.png -WhatIf

Prompt before extraction:

.\Get-LastFrame.ps1 -Video video.mp4 -Image frame.png -Frame 100 -Confirm