$(".prev").hide();

var btnNext = $('.next'),
    btnPrev = $('.prev'),
    tv_main_channel_mp4 = $('#mp4source'),
    tv_main_channel_ogv = $('#ogvsource'),
    tv_main_channel_webm = $('#webmsource'),
    d_program_source_mp4 = ("landing.mp4"),
    d_program_source_ogv = ("landing.ogv"),
    d_program_source_webm = ("landing.webm"),
    video_block = $('#video_background');

$(btnNext, btnPrev).on('click', function () {
    tv_main_channel_mp4.attr('src', d_program_source_mp4);
    tv_main_channel_ogv.attr('src', d_program_source_ogv);
    tv_main_channel_webm.attr('src', d_program_source_webm);

    video_block.load();

    $(btnNext, btnPrev).toggle();
});