$JSON = @"
[{
    "Subtitle": {
        "Search": {
            "Burn": false,
            "Default": false,
            "Enable": false,
            "Forced": false
        },
        "SubtitleList": [{
            "Burn": false,
            "Default": false,
            "Forced": false,
            "ID": 1,
            "Offset": 0,
            "Track": 0
        }]
    }
}]
"@

$JSON = ($JSON | ConvertFrom-Json);

$JSON | % {
    If(($_.Subtitle.SubtitleList[0].ID -eq 1) -and ($_.Subtitle.SubtitleList[0].Track -eq 0))
    {
        If (!($_.Subtitle.SubtitleList[0].Default = "true"))
        {
            $_.Subtitle.SubtitleList[0].Default = "true";
        }
    }
};
$x = $JSON | ConvertTo-Json -depth 32;