share/lua/media/youtube.lua

   1 -- libquvi-scripts
   2 -- Copyright (C) 2010-2012  Toni Gundogdu <legatvs@gmail.com>
   3 --
   4 -- This file is part of libquvi-scripts <http://quvi.sourceforge.net/>.
   5 --
   6 -- This library is free software; you can redistribute it and/or
   7 -- modify it under the terms of the GNU Lesser General Public
   8 -- License as published by the Free Software Foundation; either
   9 -- version 2.1 of the License, or (at your option) any later version.
  10 --
  11 -- This library is distributed in the hope that it will be useful,
  12 -- but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 -- Lesser General Public License for more details.
  15 --
  16 -- You should have received a copy of the GNU Lesser General Public
  17 -- License along with this library; if not, write to the Free Software
  18 -- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 -- 02110-1301  USA
  20 --
  21
  22 local YouTube = {} -- Utility functions unique to this script
  23
  24 -- <http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs>
  25
  26 -- Identify the script.
  27 function ident(qargs)
  28   local A = require 'quvi/accepts'
  29   local Y = require 'quvi/youtube'
  30   local C = require 'quvi/const'
  31   local u = Y.normalize(qargs.input_url)
  32   local r = {
  33     accepts = A.accepts(u, {"youtube%.com"}, {"/watch"}, {"v=[%w-_]+"}),
  34     categories = C.qmspc_http
  35   }
  36   return r
  37 end
  38
  39 -- Parse media properties.
  40 function parse(qargs)
  41   local Y = require 'quvi/youtube'
  42   return YouTube.parse_properties(qargs, Y)
  43 end
  44
  45 --
  46 -- Utility functions
  47 --
  48
  49 -- Parses the video info from the server.
  50 function YouTube.parse_properties(qargs, Y)
  51   local c, U = YouTube.get_data(qargs, Y)
  52
  53   qargs.duration_ms = (c['length_seconds'] or 0)*1000 -- to ms
  54   qargs.thumb_url = U.unescape(c['thumbnail_url'] or '')
  55   qargs.title = U.unescape(c['title'] or '')
  56   qargs.streams = YouTube.iter_streams(c, U)
  57   YouTube.append_begin_param(qargs)
  58
  59   return qargs
  60 end
  61
  62 -- Queries the video data from the server.
  63 function YouTube.get_data(qargs, Y)
  64   local u = Y.normalize(qargs.input_url)
  65
  66   qargs.id = u:match('v=([%w-_]+)')
  67               or error('no match: media ID')
  68
  69   local U = require 'quvi/url'
  70   local u = U.parse(u)
  71   local s = u.scheme or error('no match: scheme')
  72
  73   local s_fmt = '%s://www.youtube.com/get_video_info?&video_id=%s'
  74                   .. '&el=detailpage&ps=default&eurl=&gl=US&hl=en'
  75   local u = string.format(s_fmt, s, qargs.id)
  76
  77   local C = require 'quvi/const'
  78   local U = require 'quvi/util'
  79
  80   local o = { [C.qfo_type] = C.qft_config }
  81   local c = U.decode(quvi.fetch(u, o))
  82
  83   if c['reason'] then
  84     local reason = U.unescape(c['reason'])
  85     local code = c['errorcode']
  86     error(string.format("%s (code=%s)", reason, code))
  87   end
  88
  89   return c, U
  90 end
  91
  92 -- Appends the &begin parameter to the media stream URL.
  93 function YouTube.append_begin_param(qargs)
  94   local m,s = qargs.input_url:match('t=(%d?%d?m?)(%d%d)s')
  95   m = tonumber(((m or ''):gsub('%a',''))) or 0
  96   s = tonumber(((s or ''):gsub('%a',''))) or 0
  97   local ms = (m*60000) + (s*1000)
  98   if ms >0 then
  99     for i,v in ipairs(qargs.streams) do
 100       local url = qargs.streams[i].url
 101       qargs.streams[i].url = url .."&begin=".. ms
 102     end
 103     qargs.start_time_ms = ms
 104   end
 105 end
 106
 107 -- Iterates the available streams.
 108 function YouTube.iter_streams(config, U)
 109
 110   -- Stream map. Holds many of the essential properties,
 111   -- e.g. the media stream URL.
 112
 113   local stream_map = U.unescape(config['url_encoded_fmt_stream_map']
 114                       or error('no match: url_encoded_fmt_stream_map'))
 115                         .. ','
 116
 117   local smr = {}
 118   for d in stream_map:gmatch('([^,]*),') do
 119     local d = U.decode(d)
 120     if d['url'] then
 121       local ct = U.unescape(d['type'])
 122       local v_enc,a_enc = ct:match('codecs="([%w.]+),%s+([%w.]+)"')
 123       local itag = d['itag']
 124       local cnt = (ct:match('/([%w-]+)')):gsub('x%-', '')
 125       local t = {
 126         url = U.unescape(d['url']),
 127         quality = d['quality'],
 128         container = cnt,
 129         v_enc = v_enc,
 130         a_enc = a_enc
 131       }
 132       smr[itag] = t
 133     end
 134   end
 135
 136   -- Format list. Combined with the above properties. This list is used
 137   -- for collecting the video resolution.
 138
 139   local fmtl = U.unescape(config['fmt_list'] or error('no match: fmt_list'))
 140   local S = require 'quvi/stream'
 141   local r = {}
 142
 143   for itag,w,h in fmtl:gmatch('(%d+)/(%d+)x(%d+)') do
 144     local smri = smr[itag]
 145     local t = S.stream_new(smri.url)
 146
 147     t.video.encoding = smri.v_enc or ''
 148     t.audio.encoding = smri.a_enc or ''
 149     t.container = smri.container or ''
 150     t.video.height = tonumber(h)
 151     t.video.width = tonumber(w)
 152
 153     -- Do this after we have the video resolution, as the to_id
 154     -- function uses the height property.
 155     t.id = YouTube.to_id(t, itag, smri)
 156
 157     table.insert(r, t)
 158   end
 159
 160   if #r >1 then
 161     YouTube.ch_best(S, r) -- Pick one stream as the 'best' quality.
 162   end
 163
 164   return r
 165 end
 166
 167 -- Picks the stream with the highest video height property
 168 -- as the best in quality.
 169 function YouTube.ch_best(S, t)
 170   local r = t[1] -- Make the first one the 'best' by default.
 171   r.flags.best = true
 172   for _,v in pairs(t) do
 173     if v.video.height > r.video.height then
 174       r = S.swap_best(r, v)
 175     end
 176   end
 177 end
 178
 179 -- Return an ID for a stream.
 180 function YouTube.to_id(t, itag, smri)
 181   return string.format("%s_%s_i%02d_%sp",
 182           smri.quality, t.container, itag, t.video.height)
 183 end
 184
 185 -- vim: set ts=2 sw=2 tw=72 expandtab: