You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: get_video_file_writer.m
    path of file: ./repos/flow_registration/util/io
    
    the code of the file until where you have to start completion: % Author   : Philipp Flotho
% Copyright 2021 by Philipp Flot
    
function video_writer = get_video_file_writer(filename, ...
    output_format, varargin)
%GET_VIDEO_FILE_WRITER constructs video file writers

    if (nargin < 3)
        ds_name = [];
    end