vk.com - big Russian social network.
Including videos from there should also be possible by video_filter
Thanks for nice hooks, it did not make much time to write a hook adding this functionality:

function customsite_codec_info() {
    $codecs = array();
    $codecs['vk'] = array(
        'name' => t('VK'),
        'callback' => 'customsite_vk',
        'regexp' => '/vk\.com\/video([0-9]+)\_([0-9]+)\?hash=([a-z0-9]+)/i',
        'ratio' => 607 / 360,
    );
    return $codecs;
}
function customsite_vk($video) {
    $video['source'] = 'http://vk.com/video_ext.php?oid='.$video['codec']['matches'][1]."&id=".$video['codec']['matches'][2]."&hash=".$video['codec']['matches'][3]."&hd=1";
    return video_filter_iframe($video);
}

Transformation:
http://vk.com/video92267979_164947616?hash=bb7c2f9646236401
->
http://vk.com/video_ext.php?oid=92267979&id=164947616&hash=bb7c2f9646236...

However, I think this could be added to the main branch.