def add_libav_on_win(ext):
    """ no pkg-config on windows, simply assume these libs are available """
    ext.libraries += ['avformat', 'avutil', 'avcodec', 'swresample']
    for define_macro in ['HAVE_LIBAV', 'HAVE_SWRESAMPLE']:
        ext.define_macros += [(define_macro, 1)]
