I got plupload working directly to Amazon S3 with this sample code.I got the Direct Browser to S3 Upload using temporary credentials.
Now I need to generate expiring Amazon S3 Link and using those temporary credentials need to implement the Plupload. ie I need to mix both the cases mentioned above.So I generate the url and put it as the url in the following code.
<script type="text/javascript">
$(function() {
$("#uploader").plupload({
    runtimes : 'flash,silverlight',
    url : 'TEMPORARY URL',
    max_file_size : '10mb',
    multipart: true,
    multipart_params: {
        'key': '${filename}', 
        'Filename': '${filename}',
        'acl': 'public-read',
        'Content-Type': 'image/jpeg',
        'success_action_status': '201'
    },
    file_data_name: 'file',
    multiple_queues: true,
    filters : [
        {title : "JPEG files", extensions : "jpg"}
    ],
    flash_swf_url : '../../js/plupload.flash.swf',
    silverlight_xap_url : '../../js/plupload.silverlight.xap'
});
});
</script>
Generate Expiring Amazon S3 Link
<?php 
$S3_KEY='S3 Key Here';
$S3_SECRET='S3 Secret Here';
$S3_BUCKET='/uploadtestbucket';
$EXPIRE_TIME=(60 * 5); // 5 minutes
$S3_URL='http://s3.amazonaws.com';
$objectName='/' . $_GET['name'];
$mimeType=$_GET['type'];
$expires = time() + $EXPIRE_TIME;
$amzHeaders= "x-amz-acl:public-read";
$stringToSign = "PUT\n\n$mimeType\n$expires\n$amzHeaders\n$S3_BUCKET$objectName";
$sig = urlencode(base64_encode(hash_hmac('sha1', $stringToSign, $S3_SECRET, true)));
$url = urlencode("$S3_URL$S3_BUCKET$objectName?    AWSAccessKeyId=$S3_KEY&Expires=$expires&Signature=$sig");
echo $url;
?>
But I am getting this error
IO error. Error #2032
My reference links are
- How do I make Plupload upload directly to Amazon S3?
 - Upload directly to Amazon S3 using Plupload HTML5 runtime
 
What is the mistake in my code??