Tcpdf issue with display hindi language font

I am using Tcpdf PHP library to generate PDF. I got issue with display in Hindi language fonts in generated PDF. I have all things like fonts characters standards etc.. properly but my generated PDF contains ?????? instead of Hindi fonts. please have a look I have included my code here.

<?php
//============================================================+
// File name   : example_001.php
// Begin       : 2008-03-04
// Last Update : 2013-05-14
//
// Description : Example 001 for TCPDF class
//               Default Header and Footer
//
// Author: Nicola Asuni
//
// (c) Copyright:
//               Nicola Asuni
//               Tecnick.com LTD
//               www.tecnick.com
//               info@tecnick.com
//============================================================+

/**
 * Creates an example PDF TEST document using TCPDF
 * @package com.tecnick.tcpdf
 * @abstract TCPDF - Example: Default Header and Footer
 * @author Nicola Asuni
 * @since 2008-03-04
 */

// Include the main TCPDF library (search for installation path).
require_once('tcpdf_include.php');

// create new PDF document
$pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);

// set document information
$pdf->SetCreator(PDF_CREATOR);
$pdf->SetAuthor('Nicola Asuni');
$pdf->SetTitle('TCPDF Example 001');
$pdf->SetSubject('TCPDF Tutorial');
$pdf->SetKeywords('TCPDF, PDF, example, test, guide');

// set default header data
$pdf->SetHeaderData(PDF_HEADER_LOGO, PDF_HEADER_LOGO_WIDTH, PDF_HEADER_TITLE.' 001', PDF_HEADER_STRING, array(0,64,255), array(0,64,128));
$pdf->setFooterData(array(0,64,0), array(0,64,128));

// set header and footer fonts
$pdf->setHeaderFont(Array(PDF_FONT_NAME_MAIN, '', PDF_FONT_SIZE_MAIN));
$pdf->setFooterFont(Array(PDF_FONT_NAME_DATA, '', PDF_FONT_SIZE_DATA));

// set default monospaced font
//$pdf->SetDefaultMonospacedFont(PDF_FONT_MONOSPACED);

// set margins
$pdf->SetMargins(PDF_MARGIN_LEFT, PDF_MARGIN_TOP, PDF_MARGIN_RIGHT);
$pdf->SetHeaderMargin(PDF_MARGIN_HEADER);
$pdf->SetFooterMargin(PDF_MARGIN_FOOTER);

// set auto page breaks
$pdf->SetAutoPageBreak(TRUE, PDF_MARGIN_BOTTOM);

// set image scale factor
$pdf->setImageScale(PDF_IMAGE_SCALE_RATIO);



TCPDF_FONTS::addTTFfont('../fonts/Devanagari/Devanagari.ttf', 'TrueTypeUnicode', "", 32);
// ---------------------------------------------------------

// set default font subsetting mode
$pdf->setFontSubsetting(true);

// Set font
// dejavusans is a UTF-8 Unicode font, if you only need to
// print standard ASCII chars, you can use core fonts like
// helvetica or times to reduce file size.
$pdf->SetFont('Devanagari', '', 14, '', true);

// Add a page
// This method has several options, check the source code documentation for more information.
$pdf->AddPage();

// set text shadow effect
$pdf->setTextShadow(array('enabled'=>true, 'depth_w'=>0.2, 'depth_h'=>0.2, 'color'=>array(196,196,196), 'opacity'=>1, 'blend_mode'=>'Normal'));

// Set some content to print
$html = "प्रविष्टि कर कुल बिक्री मूल्य वेट के साथ
भार(ग्रा) टिन मात्रा(सं) भुगतान का प्रकार विवरण जारीकर्ता कार्ड";

// Print text using writeHTMLCell()
$pdf->writeHTMLCell(0, 0, '', '', $html, 0, 1, 0, true, '', true);

// ---------------------------------------------------------

// Close and output PDF document
// This method has several options, check the source code documentation for more information.
$pdf->Output('example_001.pdf', 'I');

//============================================================+
// END OF FILE
//============================================================+

please help to solve my issue.

Try this:

$pdf->writeHTMLCell(0, 0, '', '', utf8_encode($html), 0, 1, 0, true, '', true);