shell-x script for combining video files and converting them into HEVC format with GPU Encoder

07.Combine (hevc, same bitrate).c.ps1

# Combine (hevc, same bitrate unless picked by user).c.ps1
# This script combines multiple videos into a single hevc video with the same bitrate and quality.
# Author: Venipa <admin@venipa.net>
# License: MIT
# Version: 1.1.0
# - Updated missing audio fallback with silence, fixed duration of the silence triggering X buffers queued in out_X_1
# - ffprobe per file for audio and duration check
# - size down subsequent video aspect ratios to the first sequence
# Version: 1.0.0
# Date: 2026-03-06
# Usage: Combine (hevc, same bitrate).c.ps1 <input files>

function ParseFileArguments {
  param (
    [string]$inputString
  )

  # Pattern matches A:\, C:\, etc., and captures until next <drive>:\ or end of string.
  $regex = '([a-zA-Z]:\\.*?)(?=\s+[a-zA-Z]:\\|$)'
  $regexMatches = [regex]::Matches($inputString, $regex)
  $fileList = @()
  foreach ($match in $regexMatches) {
    $escapedValue = $match.Groups[1].Value.Trim() -replace '\[', '``[' -replace '\]', '``]'
    $fileList += $escapedValue
  }
  return $fileList
}

Write-Debug "Arguments:`n$args`n`n"

function getInputResolution {
  param (
    [string]$inputPath
  )
  $ffprobePath = "$env:ChocolateyInstall\bin\ffprobe.exe"
  if (-not (Test-Path $ffprobePath)) {
    $ffprobePath = "ffprobe"
  }
  $ffprobeCmd = @(
    "-v", "error"
    "-select_streams", "v:0"
    "-show_entries", "stream=width,height"
    "-of", "csv=s=x:p=0"
    "`"$inputPath`""
  )
  $ffprobeOutput = & $ffprobePath @ffprobeCmd
  if ($LASTEXITCODE -eq 0 -and $ffprobeOutput -match "^(\d+)x(\d+)$") {
    $width = $matches[1]
    $height = $matches[2]
    return $width, $height
  }
  return $null, $null
}
$args = ParseFileArguments($args -join ' ') | sort-object
if ($args.Count -eq 0 -or $args.Count -eq 1) {
  Write-Host "Please provide at least 2 input files!";

  Pause
  exit 1
}
$defaultQuality = 30
$maxQuality = 51
$minQuality = 10

$defaultWidth = 1920
$defaultHeight = 1080
# Prompt for quality
$quality = Read-Host "Quality ($minQuality-$maxQuality, default $defaultQuality)"
if ([string]::IsNullOrWhiteSpace($quality)) {
  $quality = $defaultQuality
}

# Make sure quality is an integer between 10 and 51
try {
  $quality = [int]$quality
}
catch {
  $quality = $defaultQuality
}
if ($quality -lt $minQuality) { $quality = $minQuality }
if ($quality -gt $maxQuality) { $quality = $maxQuality }

$inputs = @()

foreach ($filepath in $args) {
  if (Test-Path $filepath) {
    $file = Get-Item $filepath
    $inputs += $file
  }
}
if ($inputs.Count -eq 0) {
  Write-Host "No input files provided!"; Pause; exit 1
}
Write-Host "Converting to HEVC with quality CRF $quality and resolution $width x $height"

$cInputs = @()
$cFilters = @()
$cInputCount = 0
$firstInput = $inputs[0]
$width, $height = getInputResolution($firstInput.FullName)
if ($null -eq $width -or $null -eq $height) {
  Write-Host "Could not determine input resolution, using defaults."
  $width = $defaultWidth
  $height = $defaultHeight
}
else {
  $width = [int]$width
  $height = [int]$height
}
foreach ($inputPath in $inputs) {
  $escapedInputPath = [System.IO.Path]::GetFullPath($inputPath.FullName)
  $probe = & ffprobe -v error -select_streams a:0 -show_entries stream=codec_type:format=duration -of default=noprint_wrappers=1 "`"$escapedInputPath`""
  $hasAudio = $probe -match "audio"
  $duration = [float]($probe | Select-String "duration=(\d+\.?\d*)").Matches.Groups[1].Value

  $cInputs += "-hwaccel", "cuda", "-i", "`"$escapedInputPath`""
  $cFilters += "[$($cInputCount):v]format=yuv420p,scale=${width}:${height}:force_original_aspect_ratio=decrease,pad=${width}:${height}:(ow-iw)/2:(oh-ih)/2,setsar=1[v$($cInputCount)];"

  if ($hasAudio -match "audio") {
    $cFilters += "[$($cInputCount):a]atrim=duration=${duration},asetpts=PTS-STARTPTS[a$($cInputCount)];"
  }
  else {
    $cFilters += "anullsrc=channel_layout=stereo:sample_rate=48000,atrim=duration=${duration},asetpts=PTS-STARTPTS[a$($cInputCount)];"
  }
  $cInputCount++
}
$cFormatCount = 0
foreach ($inputPath in $inputs) {
  $cFormats += "`[v$($cFormatCount)`]`[a$($cFormatCount)`]"
  $cFormatCount++
}
$cFormatsJoined = ([string]::Join("", $cFormats))


# Output filename (based on first input)
$firstInput = $inputs[0]
$firstInputBase = [System.IO.Path]::Combine(
  [System.IO.Path]::GetDirectoryName($firstInput),
  ([System.IO.Path]::GetFileNameWithoutExtension($firstInput) + "-combined-hevc.mp4")
)
$oFilename = $firstInputBase

# Compose filter_complex
$cFiltersJoined = ([string]::Join("", $cFilters)) + $cFormatsJoined + "concat=n=$($cInputCount):v=1:a=1[v][a]"

Write-Host "`n`nConverting $cInputCount inputs to HEVC with quality CRF $quality"
Write-Host "Inputs: $([string]::Join(" ", $cInputs))"
Write-Host "Filters: $([string]::Join(" ", $cFiltersJoined))"
Write-Host "Output: $oFilename`n`n"

# Find ffmpeg
$ffmpegPath = "$env:ChocolateyInstall\bin\ffmpeg.exe"
if (-not (Test-Path $ffmpegPath)) {
  $ffmpegPath = "ffmpeg"
}




# Construct argument list
$ffmpegArgs = @(
  "-hide_banner",
  "-y"
)
foreach ($ffmpegInput in $cInputs) {
  $ffmpegArgs += $ffmpegInput
}
$ffmpegArgs += @(
  "-filter_complex", "`"$($cFiltersJoined)`""
  "-map", "`"[v]`""
  "-map", "`"[a]`""
  "-noautoscale",
  "-c:v", "hevc_nvenc"
  "-preset:v", "p7"
  "-tune:v", "hq"
  "-rc:v", "vbr"
  "-cq:v", "$quality"
  "-b:v", "0"
  "-maxrate:v", "10M"
  "-b:a", "128k"
  "-ac", "2"
  "`"$oFilename`""
)
try {
  # write-Host "FFmpeg Command:`n $ffmpegPath $([string]::Join(" ", $ffmpegArgs))"
  # Run ffmpeg
  Invoke-Expression "$ffmpegPath $([string]::Join(" ", $ffmpegArgs))"

  if ($LASTEXITCODE -ne 0) {
    Write-Host "Error occurred during ffmpeg execution."
    pause
    exit 1
  }
}
catch {
  Write-Error "Error occurred during ffmpeg execution: `n`n$_`n`n"
  pause
  exit 1
}
Write-Host "Conversion completed successfully."
Pause
exit 0

Combined 27 video files.
Example:
https://up.venipa.net/view/ragged-babyish-bat.mp4