jQuery Unexpected token in JSON for valid input

I am getting the below error. I am not sure where I get the ' symbol in the JSON. I have double checked and sure that the json_encode function of PHP does not add the ' symbol in the first position.

I have seen other question and solutions in StackOverflow and could not find any other solution in Google for this particular scenario.

SyntaxError: Unexpected token ' in JSON at position 0
    at parse (<anonymous>)
    at e.parseJSON (jquery-migrate.min.js:2)
    at fn (jquery.min.js:6)
    at k (jquery.min.js:6)
    at XMLHttpRequest.<anonymous> (jquery.min.js:6)

Below is the PHP code which generates the JSON string.

$info = Embed\Embed::create($videoUrl);

$result = array();

$result['title'] = $info->title;
$result['desciption'] = $info->description;
$result['type'] = $info->type;
$result['tags'] = $info->tags;
$result['provider'] = $info->providerName;

echo json_encode($result,true);

Below is the jQuery used to do a post action.

$(document).ready(function () {

    $("#videoUrl").blur(function (event) {

        if ($(this).val() != '') {

            $.ajax({
                type: 'POST',
                url: '/url-here',
                dataType: 'json',
                data: {
                    "value": $(this).val()
                },
                success: function (msg) {
                    alert("Data Saved: " + msg);
                },
                error: function (XMLHttpRequest, textStatus, errorThrown) {
                    console.log(errorThrown.message);
                }
            })
        }

    });

});

The sample response as found in the Chrome console is provided for your reference.

'{"title":"Inside of big gold mine in Africa. How it works. Documentary.","desciption":"Deepest mine in Africa.","type":"video","tags":["Megastructures","mine","gold","deepest mine","documentary","Deepest","how it works"],"provider":"YouTube"}

EDIT:

As requested I am sharing the entire php code.

public function getVideoDetails() {
   OW::getResponse()->clearHeaders();
   OW::getResponse()->setHeader('Content-Type', 'application/json; charset=utf-8');

   $videoUrl = $_POST['value'];

   $info = Embed\Embed::create($videoUrl);

   $result = array();

   $result['title'] = $info->title;
   $result['description'] = $info->description;
   $result['type'] = $info->type;
   $result['tags'] = $info->tags;
   //$result['image'] = $info->image;
   $result['provider'] = $info->providerName;

   echo json_encode($result, true);

   OW::getResponse() - > sendHeaders();
   exit;
}