PowerPoint Automation Service Application - SharePoint 2013 - Timeout Error

I am using PowerPoint Automation Service application to convert .pptx to JPEG files.  The service application is throwing error after 5 mins of execution.  The following code has been used in the function.  

AsyncResult operation exceeded timeout of 00:05:00

 byte[] byteArray = filename.OpenBinary();

using (MemoryStream mem = new MemoryStream())
 {
                            mem.Write(byteArray, 0, (int)byteArray.Length);
                            SPFileStream stream = new SPFileStream(web, 0x1000);

                            PictureRequest imagesRequest = new PictureRequest(mem, ".pptx", Microsoft.Office.Server.PowerPoint.Conversion.PictureFormat.Png, stream);

                            IAsyncResult result = imagesRequest.BeginConvert(
                                SPServiceContext.GetContext(site), null, null);

 


                            imagesRequest.EndConvert(result);

}