How to upload image or video or Document in asset library using Server Object Model SharePoint?

using (SPSite site = new SPSite(SPContext.Current.Site.Url))
{
using (SPWeb web = site.OpenWeb())
{ web.AllowUnsafeUpdates = true;
string value = ddlformat.SelectedItem.Text;
web.AllowUnsafeUpdates = false;
Stream StreamImage = null;
if (uploader.HasFile)
{
StreamImage = uploader.PostedFile.InputStream;
}
SPList pics = web.Lists.TryGetList("AudioLibrary");
string fileExt = Convert.ToString(uploader.FileName);
fileExt = fileExt.Split('.')[0];
fileExt= fileExt + value;
if (pics != null)
{
SPListItem picItem = pics.Items.Add();
if (pics != null)
{
web.AllowUnsafeUpdates = true;
// Stream ggg=new Stream();
SPFile ofile = pics.RootFolder.Files.Add(fileExt, StreamImage, true);
ofile.Update();
web.AllowUnsafeUpdates = false;
}
}
}
}