There are two variables which restrict the maximum media upload size to wordpress. There are PHP variables.
upload_max_filesize post_max_size
Assuming that you are using Ubuntu and Apache then you should create a .ini file in the conf.d directory. Don’t edit the default php.ini file because this is sometimes updated by the package maintainer and there is a chance that any changed you make to might be lost. So create a file called:
/etc/php5/apache2/conf.d/wordpress.ini
I wanted up be able to upload 30 megabyte files and so put:
upload_max_filesize = 30M post_max_size = 30M
Then restart Apache:
apache2ctl restart
I hope this helps someone.