Create random screenshots out of video (requires ffmpeg and mediainfo)

random_screenshots.ps1

# Requires 'ffmpeg' and 'mediainfo' in path

# For batch:
# foreach($f in Get-ChildItem .) { .\random_screenshots.ps1 $f }

$infile = $Args[0] # Input video

# Get some video length info using Mediainfo
$length_in_ms = mediainfo --Output='General;%Duration%' "$infile" | Out-String
$length_in_secs = $length_in_ms/1000

# Create output folder
$outfolder = "./screenshots/"
If(!(test-path $outfolder)) {
md $outfolder
}

# Create this many screenshots, or base it on video length
#$how_many = 10 # maybe make this the 2nd arg in the future?
$how_many = [math]::Round($length_in_secs/100)
Write-Host "Will create $how_many screenshots"

$used_seconds = @()
$i = 1
while($i -le $how_many) {
    # Get a random second of the video that hasnt been already used
    $random_sec = get-random -maximum $length_in_secs
    $rounded = [math]::Round($random_sec)
    if ($used_seconds.Contains($rounded) -eq $True) {
        while ($used_seconds.Contains($rounded) -eq $True) {
            #Write-Host $rounded "already used"
            #Write-Host $used_seconds
            $random_sec = get-random -maximum $length_in_secs
            $rounded = [math]::Round($random_sec)
        }
        #Write-Host "Found unused" $rounded
    }
    $used_seconds += $rounded

    # Outfile that screenshot will be saved as
    $outfile = $outfolder + $infile + "_" + $rounded + ".png"

    Write-Host $i/$how_many $outfile
    ffmpeg -loglevel error -ss $rounded -i "$infile" -frames:v 1 $outfile

    $i++
}