Получить содержимое attachments -> video [JSON] Java

Имеется следующая структура JSON:

{
"response": {
"count": 10,
"items": [{
"id": 104755,
"from_id": -80682837,
"owner_id": -80682837,
"date": 1483803000,
"marked_as_ads": 0,
"post_type": "postpone",
"text": "#cool@anicoubs.
ReIN ✸ Mercy Me ✸ VIP ✸",
"can_edit": 1,
"created_by": 61357957,
"can_publish": 1,
"can_delete": 1,
"attachments": [{
"type": "video",
"video": {
"id": 456243897,
"owner_id": -127727878,
"title": "ReIN ✸ Mercy Me ✸ VIP ✸",
"duration": 6,
"description": "Самые крутые и короткие ролики из аниме только у нас!
- - - - - - - - - - - -
Присоединяйся! [[club80682837|AC]] [club80682837|Anime Coubs] | [club80682837|アニメコーブ]
Автор: ReIN Coub 
Теги: #anime, #amv, #coub, #acc_team, #coubamv, #coubamv, #video, #2017, #edm, #edm, #electronic, #electronicdance, #rein, #reincoub, #reincoub, #foolzeet, #5ghtthepower, #salismoondust, #venomortex, #miracle, #op, #2017, #top, #hot, #epic, #recordfm, #animevideo, #animevideo, #animevideo, #animevideo, #sonyvegaspro, #sonyvegaspro14, #ae, #adobeaftereffect, #tokyoghoul, #tokyoghoulamv, #mercyme, #vip, #xviimercymevip, #xvii, #аниме, #музыка, #амв.",
"date": 1483801275,
"comments": 0,
"views": 17,
"photo_130": "https://pp.vk.me/...ideo/s_84ca8f4e.jpg",
"photo_320": "https://pp.vk.me/...ideo/l_90217297.jpg",
"photo_640": "https://pp.vk.me/...ideo/y_7c611865.jpg",
"access_key": "43cbb785c00ac1bb0f",
"platform": "Coub",
"can_edit": 1,
"can_add": 1
}
}],
"post_source": {
"type": "api"
},
"comments": {
"count": 0,
"can_post": 0
}
}],
"profiles": [],
"groups": [{
"id": 80682837,
"name": "[AC] Anime Coubs | アニメコーブ",
"screen_name": "anicoubs",
"is_closed": 0,
"type": "page",
"is_admin": 1,
"admin_level": 3,
"is_member": 1,
"photo_50": "https://pp.vk.me/...4ea/bZj_J5bL_EM.jpg",
"photo_100": "https://pp.vk.me/...4e9/55T6C3xKJkA.jpg",
"photo_200": "https://pp.vk.me/...4e8/a_soitbpt3g.jpg"
}, {
"id": 127727878,
"name": "[AC] Anime Coubs | Repository 2",
"screen_name": "club127727878",
"is_closed": 0,
"type": "group",
"is_admin": 1,
"admin_level": 3,
"is_member": 1,
"photo_50": "https://pp.vk.me/...500/k6TkTmhCSiA.jpg",
"photo_100": "https://pp.vk.me/...4ff/Cb8hMKo9nSU.jpg",
"photo_200": "https://pp.vk.me/...4fe/6jafptAHifc.jpg"
}]
}
}

Не могу подобраться к значению в "items": [{"attachments": [{"video": {"photo_640"}}]}].
Объясните пожалуйста, как добраться то до него?

try {
    JSONObject jsonObject = (JSONObject) response.json.get("response");
    JSONArray jsonArray = (JSONArray) jsonObject.get("items");
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject post = (JSONObject) jsonArray.get(i);
        //
        Posts mv = new Posts(post.getString("text").substring(post.getString("text").indexOf('\n') + 1), GetUTC(Long.parseLong(post.getString("date"))), post.getString("id"), "photo_640.jpg");
        mvList.add(mv);
    }
    mAdapter.notifyDataSetChanged();
} catch (JSONException e) {
    e.printStackTrace();
}