share/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 u = Y.normalize(qargs.input_url)
  31   local r = {
  32     accepts = A.accepts(u, {"youtube%.com"}, {"/watch"}, {"v=[%w-_]+"})
  33   }
  34   return r
  35 end
  36
  37 -- Parse media properties.
  38 function parse(qargs)
  39   local Y = require 'quvi/youtube'
  40   return YouTube.parse_properties(qargs, Y)
  41 end
  42
  43 --
  44 -- Utility functions
  45 --
  46
  47 -- Parses the video info from the server.
  48 function YouTube.parse_properties(qargs, Y)
  49   local c, U = YouTube.get_data(qargs, Y)
  50
  51   qargs.duration_ms = (c['length_seconds'] or 0)*1000 -- to ms
  52   qargs.thumb_url = U.unescape(c['thumbnail_url'] or '')
  53   qargs.title = U.unescape(c['title'] or '')
  54   qargs.streams = YouTube.iter_streams(c, U)
  55   YouTube.append_begin_param(qargs)
  56
  57   return qargs
  58 end
  59
  60 -- Queries the video data from the server.
  61 function YouTube.get_data(qargs, Y)
  62   local u = Y.normalize(qargs.input_url)
  63
  64   qargs.id = u:match('v=([%w-_]+)')
  65               or error('no match: media ID')
  66
  67   local U = require 'quvi/url'
  68   local u = U.parse(u)
  69   local s = u.scheme or error('no match: scheme')
  70
  71   local s_fmt = '%s://www.youtube.com/get_video_info?&video_id=%s'
  72                   .. '&el=detailpage&ps=default&eurl=&gl=US&hl=en'
  73   local u = string.format(s_fmt, s, qargs.id)
  74
  75   local C = require 'quvi/const'
  76   local U = require 'quvi/util'
  77
  78   local o = { [C.qfo_type] = C.qft_config }
  79   local c = U.decode(quvi.fetch(u, o))
  80
  81   if c['reason'] then
  82     local reason = U.unescape(c['reason'])
  83     local code = c['errorcode']
  84     error(string.format("%s (code=%s)", reason, code))
  85   end
  86
  87   return c, U
  88 end
  89
  90 -- Appends the &begin parameter to the media stream URL.
  91 function YouTube.append_begin_param(qargs)
  92   local m,s = qargs.input_url:match('t=(%d?%d?m?)(%d%d)s')
  93   m = tonumber(((m or ''):gsub('%a',''))) or 0
  94   s = tonumber(((s or ''):gsub('%a',''))) or 0
  95   local ms = (m*60000) + (s*1000)
  96   if ms >0 then
  97     for i,v in ipairs(qargs.streams) do
  98       local url = qargs.streams[i].url
  99       qargs.streams[i].url = url .."&begin=".. ms
 100     end
 101     qargs.start_time_ms = ms
 102   end
 103 end
 104
 105 -- Iterates the available streams.
 106 function YouTube.iter_streams(config, U)
 107
 108   -- Stream map. Holds many of the essential properties,
 109   -- e.g. the media stream URL.
 110
 111   local stream_map = U.unescape(config['url_encoded_fmt_stream_map']
 112                       or error('no match: url_encoded_fmt_stream_map'))
 113                         .. ','
 114
 115   local smr = {}
 116   for d in stream_map:gmatch('([^,]*),') do
 117     local d = U.decode(d)
 118     if d['url'] then
 119       local ct = U.unescape(d['type'])
 120       local v_enc,a_enc = ct:match('codecs="([%w.]+),%s+([%w.]+)"')
 121       local itag = d['itag']
 122       local cnt = (ct:match('/([%w-]+)')):gsub('x%-', '')
 123       local t = {
 124         url = U.unescape(d['url']),
 125         quality = d['quality'],
 126         container = cnt,
 127         v_enc = v_enc,
 128         a_enc = a_enc
 129       }
 130       smr[itag] = t
 131     end
 132   end
 133
 134   -- Format list. Combined with the above properties. This list is used
 135   -- for collecting the video resolution.
 136
 137   local fmtl = U.unescape(config['fmt_list'] or error('no match: fmt_list'))
 138   local S = require 'quvi/stream'
 139   local r = {}
 140
 141   for itag,w,h in fmtl:gmatch('(%d+)/(%d+)x(%d+)') do
 142     local smri = smr[itag]
 143     local t = S.stream_new(smri.url)
 144
 145     t.video.encoding = smri.v_enc or ''
 146     t.audio.encoding = smri.a_enc or ''
 147     t.container = smri.container or ''
 148     t.video.height = tonumber(h)
 149     t.video.width = tonumber(w)
 150
 151     -- Do this after we have the video resolution, as the to_id
 152     -- function uses the height property.
 153     t.id = YouTube.to_id(t, itag, smri)
 154
 155     table.insert(r, t)
 156   end
 157
 158   if #r >1 then
 159     YouTube.ch_best(S, r) -- Pick one stream as the 'best' quality.
 160   end
 161
 162   return r
 163 end
 164
 165 -- Picks the stream with the highest video height property
 166 -- as the best in quality.
 167 function YouTube.ch_best(S, t)
 168   local r = t[1] -- Make the first one the 'best' by default.
 169   r.flags.best = true
 170   for _,v in pairs(t) do
 171     if v.video.height > r.video.height then
 172       r = S.swap_best(r, v)
 173     end
 174   end
 175 end
 176
 177 -- Return an ID for a stream.
 178 function YouTube.to_id(t, itag, smri)
 179   return string.format("%s_%s_i%02d_%sp",
 180           smri.quality, t.container, itag, t.video.height)
 181 end
 182
 183 -- vim: set ts=2 sw=2 tw=72 expandtab: