help with rewrite_tag and rewrite_rule for custom page GET variables [duplicate]

You should use get_query_var rather than $_GET. But you will need to register you custom variables, for instance:

add_filter('query_vars', 'register_my_query_vars' );
function register_my_query_vars( $qvars ){
    //Add these query variables
    $qvars[] = 'video_id';
    $qvars[] = 'vide_title';
    $qvars[] = 'venue_src';

    return $qvars;
}

Then you should be able to use get_query_var('venue_id').