Split full-disc FLAC images into frame-accurate, lossless individual tracks using EAC .cue sheets and FFmpeg

Split-FlacCue.bat

@ECHO OFF
cd /d "%~dp0"
PowerShell.exe -NoProfile -ExecutionPolicy Bypass -Command "& '%~dpn0.ps1' \"%1\" \"%2\" \"%3\" \"%4\" \"%5\" \"%6\" \"%7\" \"%8\""
@PAUSE

Split-FlacCue.ps1

param([string]$cueFile)

# Ensure strict error handling
$ErrorActionPreference = "Stop"

if (-not $cueFile -or -not (Test-Path $cueFile)) {
	Write-Host "Error: Please drag and drop a valid .cue file." -ForegroundColor Red
	pause
	return
}

$workingDir = Split-Path $cueFile
$baseName = [System.IO.Path]::GetFileNameWithoutExtension($cueFile)
$flacFile = Join-Path $workingDir "$baseName.flac"

if (-not (Test-Path $flacFile)) {
	Write-Host "Error: Could not find matching FLAC file: $flacFile" -ForegroundColor Red
	pause
	return
}

# Explicitly cast global matches to strings before parsing
function Convert-CueTime ([string]$cueTime) {
	if ($cueTime -match "(\d{2}):(\d{2}):(\d{2})") {
		[int]$mins = [int]$Matches[1]
		[int]$secs = [int]$Matches[2]
		[int]$frames = [int]$Matches[3]
        
		[int]$hours = [math]::Floor($mins / 60)
		[int]$remMins = $mins % 60
		[int]$ms = [math]::Round(($frames / 75) * 1000)
        
		return "{0:D2}:{1:D2}:{2:D2}.{3:D3}" -f $hours, $remMins, $secs, $ms
	}
	throw "Failed to parse timestamp string: $cueTime"
}

# Parse CUE file securely
try {
	$cueContent = Get-Content $cueFile
}
catch {
	Write-Host "Error: Failed to read CUE sheet layout text." -ForegroundColor Red
	pause
	return
}

$tracks = @()
$currentTrack = $null

foreach ($line in $cueContent) {
	$line = $line.Trim()
	if ($line -match '^TRACK\s+(\d+)\s+AUDIO') {
		if ($currentTrack) { $tracks += $currentTrack }
		$currentTrack = @{ Number = $Matches[1]; Title = "Track_" + $Matches[1]; Start = $null }
	}
	elseif ($line -match '^TITLE\s+"([^"]+)"' -and $currentTrack) {
		$currentTrack.Title = $Matches[1] -replace '[\/?:*""<>|]', ''
	}
	elseif ($line -match '^INDEX\s+01\s+(\d{2}:\d{2}:\d{2})' -and $currentTrack) {
		$currentTrack.Start = Convert-CueTime $Matches[1]
	}
}
if ($currentTrack) { $tracks += $currentTrack }

if ($tracks.Count -eq 0) {
	Write-Host "Error: No valid tracks found in the CUE sheet." -ForegroundColor Red
	pause
	return
}

# Execute processing loop safely
for ($i = 0; $i -lt $tracks.Count; $i++) {
	$track = $tracks[$i]
	$num = $track.Number
	$title = $track.Title
	$start = $track.Start
    
	$outputName = Join-Path $workingDir "${num} - ${title}.flac"
    
	# Accurate Stream Copy Ordering: TIMESTAMPS MUST COME BEFORE INPUT (-i)
	$ffmpegArgs = @("-ss", $start)
    
	if ($i -lt ($tracks.Count - 1)) {
		$end = $tracks[$i + 1].Start
		$ffmpegArgs += @("-to", $end)
	}
    
	#To skip re-encoding: $ffmpegArgs += @("-i", $flacFile, "-c", "copy", $outputName, "-y")
	$ffmpegArgs += @("-i", $flacFile, "-c:a", "flac", "-compression_level", "5", $outputName, "-y")

	Write-Host "Stream Copying Track ${num}: ${title} (Start: $start)..." -ForegroundColor Cyan
    
	# Run FFmpeg and capture validation exceptions
	& ffmpeg -hide_banner -loglevel error @ffmpegArgs
    
	if ($LASTEXITCODE -ne 0) {
		Write-Host "FFmpeg aborted with exit code $LASTEXITCODE processing Track ${num}." -ForegroundColor Red
		pause
		return
	}
}

Write-Host "`nProcessing complete! All tracks successfully split using direct stream copy." -ForegroundColor Green