Convert MP4 to Animated WebP Using FFmpeg in PowerShell

This document provides a PowerShell command to batch convert all MP4 files in the current directory to animated WebP format using FFmpeg.

Prerequisites

• FFmpeg installed and added to your system PATH
• PowerShell

Command

Get-ChildItem -Filter *.mp4 | ForEach-Object {
    ffmpeg -i $_.FullName -vf "fps=15,scale=800:-1:flags=lanczos" -c:v libwebp -lossless 0 -compression_level 6 -q:v 80 -loop 0 -preset picture -an -vsync 0 "$($_.BaseName).webp"
}

Parameters Explained

• Get-ChildItem -Filter *.mp4: Finds all MP4 files in the current directory
• $_.FullName: The full path to the current MP4 file
• -vf "fps=15,scale=800:-1:flags=lanczos":
• Sets the frame rate to 15 fps
• Resizes width to 800px while maintaining aspect ratio
• Uses the lanczos scaling algorithm for better quality
• -c:v libwebp: Uses the WebP codec
• -lossless 0: Disables lossless compression
• -compression_level 6: Sets compression level (0-6)
• -q:v 80: Sets quality (0-100, where higher is better quality but larger file size)
• -loop 0: Makes the WebP loop infinitely
• -preset picture: Uses the picture preset for encoding
• -an: Removes audio
• -vsync 0: Prevents frame duplication or dropping
• "$($_.BaseName).webp": Names the output file with the same base name as the input but with .webp extension

Customization Options

You can adjust these parameters to meet your specific needs:

• Frame rate: Change fps=15 to your desired frame rate (higher values create smoother animation but larger files)
• Resolution: Modify scale=800:-1 to change the output size (e.g., scale=400:-1 for smaller files)
• Quality: Adjust -q:v 80 to balance quality vs file size:
• Lower values (e.g., 50-70): Smaller files, lower quality
• Higher values (e.g., 90-95): Larger files, higher quality
• Animation speed: Add setpts=0.5*PTS to the -vf parameter to make the animation play at 2x speed (adjust the multiplier as needed)

Example With Additional Options

Get-ChildItem -Filter *.mp4 | ForEach-Object {
    # Create a directory for the output if it doesn't exist
    if (-not (Test-Path -Path ".\webp_output")) {
        New-Item -ItemType Directory -Path ".\webp_output"
    }

    # Convert with custom settings
    ffmpeg -i $_.FullName -vf "fps=10,scale=400:-1:flags=lanczos" -c:v libwebp -lossless 0 -compression_level 6 -q:v 70 -loop 0 -preset picture -an -vsync 0 ".\webp_output\$($_.BaseName).webp"

    Write-Host "Converted $($_.Name) to WebP format"
}