error on uploading video

I get an error message that my file size is too large. My test file is less than 3kb, but upload_max_file size is 20M. Checked my php.ini file for PHP5 and it shows 20M; post_max_size shows 8M. Don’t know where else to look. Help please.

I’m not a tech person, know just enough to be dangerous–so I tread very, very carefully when looking through files and triple check before changing anything.