code:

#Requires -Version 7.1

[CmdletBinding()]
Param(
    [Parameter(Mandatory=$true,ValueFromPipeline=$true)]
    [ValidateScript({ Test-Path -Path $_ -PathType Leaf })]
    [String]$Path
)

[System.Collections.ArrayList]$Content = (Get-Content -Path $Path | Out-String).Trim().Split("`r`n`r`n")

if (!$Content) {
    throw "Insufficient content found in input file [$Path]!"
}

[System.Collections.ArrayList]$ReturnCollecton = @()

foreach ($Sub in $Content) {
    $SubContent = $Sub.Split("`r`n")

    # Each sub requires an ID, time code and text
    if ($SubContent.Count -lt 3) {
        Write-Error -Message "Subtitle element is malformed: $Sub"
        continue
    }

    $SubTimeCode = $SubContent[1].Split(' --> ')

    # Time code requires start and finish time
    if ($SubTimeCode.Count -lt 2) {
        Write-Error -Message "Subtitle time code is malformed: $Sub"
        continue
    }

    $SubObject = New-Object -TypeName 'System.Object'

    $SubObject | Add-Member -NotePropertyName 'Id' -NotePropertyValue $SubContent[0]
    $SubObject | Add-Member -NotePropertyName 'Start' -NotePropertyValue $SubTimeCode[0]
    $SubObject | Add-Member -NotePropertyName 'End' -NotePropertyValue $SubTimeCode[1]
    $SubObject | Add-Member -NotePropertyName 'Text' -NotePropertyValue ($SubContent | Select-Object -Skip 2 | Out-String).Trim("`r`n")

    $ReturnCollecton.Add($SubObject) | Out-Null
}

if (!$ReturnCollecton) {
    throw "No subtitle elements successfully parsed in input file [$Path]!"
}

return $ReturnCollecton