очень просто. Есть хороший сервис youtubex.com
На странице есть поле, куда вставляешь ссылку на youtube-видео, например _http://youtube.com/watch?v=Q275Qh4ESao, затем нажимаешь кнопку Get Video. Через некоторое время появляется прямая ссылка на флэш-ролик, который можно скачать как обычный файл.
Вообщето, keepvid.com тащит не только с youtube, но и с десятка других сервисов онлайн видео.
Посмотрел на самом сервисе(онлайн) видео полностью(чтобы закачалось), залез в кэш броузера(IE там или Firefox, или еще чего), нашел большой файл, скопировал куда-нить, добавил расширение .FLV если небыло у временного файла, и смотрю его локально.
И ничего никуда не надо лезть и повторно качать видео, но уже качалкой.
{"assets_hash":"a8b26fa7f6e768b07a72c8c9aadb9422","page_data":{"users":{"3fb510643df9550077795921":{"_id":"3fb510643df9550077795921","hid":2461,"name":"Сергей=","nick":"Сергей=","avatar_id":null,"css":""},"41fd41123df9550077792514":{"_id":"41fd41123df9550077792514","hid":5875,"name":"NailMan","nick":"NailMan","avatar_id":null,"css":""},"422c6c053df9550077791d3b":{"_id":"422c6c053df9550077791d3b","hid":6353,"name":"stanser","nick":"stanser","avatar_id":null,"css":""},"433a649a3df955007778f00f":{"_id":"433a649a3df955007778f00f","hid":9348,"name":"ivereninov","nick":"ivereninov","avatar_id":null,"css":""},"43c12b6b3df955007778d7f5":{"_id":"43c12b6b3df955007778d7f5","hid":11152,"name":"alkot","nick":"alkot","avatar_id":null,"css":""}},"settings":{"can_see_ip":false,"can_report_abuse":false,"can_see_hellbanned":false,"forum_can_view":true,"forum_can_reply":false,"forum_edit_max_time":30,"forum_can_close_topic":false,"forum_show_ignored":false,"forum_mod_can_delete_topics":false,"forum_mod_can_hard_delete_topics":false,"forum_mod_can_see_hard_deleted_topics":false,"forum_mod_can_edit_posts":false,"forum_mod_can_pin_topic":false,"forum_mod_can_edit_titles":false,"forum_mod_can_close_topic":false,"can_vote":false,"forum_mod_can_add_infractions":false,"forum_topic_title_min_length":10,"forum_reply_old_post_threshold":30,"votes_add_max_time":168,"forum_show_post_interval":7,"can_see_deleted_users":false},"section":{"_id":"61c9a54c3df9550077bb50ab","hid":6,"title":"Курилка","parent":"61c9a54c3df9550077bb5123","description":"Разговоры на общие околомодельные темы.","is_category":false,"is_votable":true,"is_writable":true,"cache":{"topic_count":8213,"post_count":312959,"last_post":"674a13ed6bffb2a544c258b5","last_topic":"672bdee8f9bb00ab89c25e0c","last_topic_hid":572564,"last_topic_title":"Уро......ы заблокировали форум!","last_ts":"2024-11-29T19:20:13.542Z","last_user":"4bf42ac43df9550077760b39"}},"topic":{"_id":"4607f5029970730077f54db1","hid":64102,"title":"Как скачать файлы с сервисов youtube и google video?","views_count":2854,"last_post_counter":5,"cache":{"post_count":5,"first_post":"4607f5029970730077f55812","first_ts":"2007-03-26T16:29:54.000Z","first_user":"433a649a3df955007778f00f","last_post":"4608e36c9970730077f5581a","last_post_hid":5,"last_ts":"2007-03-27T09:27:08.000Z","last_user":"41fd41123df9550077792514"},"st":1,"section":"61c9a54c3df9550077bb50ab"},"subscription":null,"pagination":{"total":5,"per_page":25,"chunk_offset":0},"posts_list_before_post":["paginator","datediff"]},"locale":"en-US","user_id":"000000000000000000000000","user_hid":0,"user_name":"","user_nick":"","user_avatar":null,"is_member":false,"settings":{"can_access_acp":false,"can_use_dialogs":false,"hide_heavy_content":false},"unread_dialogs":false,"footer":{"rules":{"to":"common.rules"},"contacts":{"to":"rco-nodeca.contacts"}},"navbar":{"tracker":{"to":"users.tracker","autoselect":false,"priority":10},"forum":{"to":"forum.index"},"blogs":{"to":"blogs.index"},"clubs":{"to":"clubs.index"},"market":{"to":"market.index.buy"}},"recaptcha":{"public_key":"6LcyTs0dAAAAADW_1wxPfl0IHuXxBG7vMSSX26Z4"},"layout":"common.layout"}