share/media/youtube.lua

   1 -- libquvi-scripts
   2 -- Copyright (C) 2010-2013  Toni Gundogdu <legatvs@gmail.com>
   3 --
   4 -- This file is part of libquvi-scripts <http://quvi.sourceforge.net/>.
   5 --
   6 -- This program is free software: you can redistribute it and/or
   7 -- modify it under the terms of the GNU Affero General Public
   8 -- License as published by the Free Software Foundation, either
   9 -- version 3 of the License, or (at your option) any later version.
  10 --
  11 -- This program 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
  14 -- GNU Affero General Public License for more details.
  15 --
  16 -- You should have received a copy of the GNU Affero General
  17 -- Public License along with this program.  If not, see
  18 -- <http://www.gnu.org/licenses/>.
  19 --
  20
  21 local YouTube = {} -- Utility functions unique to this script
  22
  23 -- <http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs>
  24
  25 -- Identify the script.
  26 function ident(qargs)
  27   local Y = require 'quvi/youtube'
  28   return Y.ident(qargs)
  29 end
  30
  31 -- Parse media properties.
  32 function parse(qargs)
  33   return YouTube.parse_properties(qargs)
  34 end
  35
  36 --
  37 -- Utility functions
  38 --
  39
  40 -- Parses the video info from the server.
  41 function YouTube.parse_properties(qargs)
  42   local c, U = YouTube.get_data(qargs)
  43
  44   qargs.duration_ms = (c['length_seconds'] or 0)*1000 -- to ms
  45   qargs.thumb_url = U.unescape(c['thumbnail_url'] or '')
  46   qargs.title = U.unescape(c['title'] or '')
  47   qargs.streams = YouTube.iter_streams(c, U)
  48   YouTube.append_begin_param(qargs)
  49
  50   return qargs
  51 end
  52
  53 -- Queries the video data from the server.
  54 function YouTube.get_data(qargs)
  55   local Y = require 'quvi/youtube'
  56   local u = Y.normalize(qargs.input_url)
  57
  58   qargs.id = u:match('v=([%w-_]+)')
  59               or error('no match: media ID')
  60
  61   local U = require 'socket.url'
  62   local u = U.parse(u)
  63   local s = u.scheme or error('no match: scheme')
  64
  65   local s_fmt = '%s://www.youtube.com/get_video_info?&video_id=%s'
  66                   .. '&el=detailpage&ps=default&eurl=&gl=US&hl=en'
  67   local u = string.format(s_fmt, s, qargs.id)
  68
  69   local C = require 'quvi/const'
  70   local U = require 'quvi/util'
  71
  72   local o = { [C.qfo_type] = C.qft_config }
  73   local c = U.decode(quvi.http.fetch(u,o).data)
  74
  75   if c['reason'] then
  76     local reason = U.unescape(c['reason'])
  77     local code = c['errorcode']
  78     error(string.format("%s (code=%s)", reason, code))
  79   end
  80
  81   return c, U
  82 end
  83
  84 -- Appends the &begin parameter to the media stream URL.
  85 function YouTube.append_begin_param(qargs)
  86   local m,s = qargs.input_url:match('t=(%d?%d?m?)(%d%d)s')
  87   m = tonumber(((m or ''):gsub('%a',''))) or 0
  88   s = tonumber(((s or ''):gsub('%a',''))) or 0
  89   local ms = (m*60000) + (s*1000)
  90   if ms >0 then
  91     for i,v in ipairs(qargs.streams) do
  92       local url = qargs.streams[i].url
  93       qargs.streams[i].url = url .."&begin=".. ms
  94     end
  95     qargs.start_time_ms = ms
  96   end
  97 end
  98
  99 -- Iterates the available streams.
 100 function YouTube.iter_streams(config, U)
 101
 102   -- Stream map. Holds many of the essential properties,
 103   -- e.g. the media stream URL.
 104
 105   local stream_map = U.unescape(config['url_encoded_fmt_stream_map']
 106                       or error('no match: url_encoded_fmt_stream_map'))
 107                         .. ','
 108
 109   local smr = {}
 110   for d in stream_map:gmatch('([^,]*),') do
 111     local d = U.decode(d)
 112     if d['url'] then
 113       local ct = U.unescape(d['type'])
 114       local v_enc,a_enc = ct:match('codecs="([%w.]+),%s+([%w.]+)"')
 115       local itag = d['itag']
 116       local cnt = (ct:match('/([%w-]+)')):gsub('x%-', '')
 117       local t = {
 118         url = U.unescape(d['url']) -- d['sig'] ? "&signature=val" : ""
 119               .. (d['sig'] and ('&signature='..d['sig']) or ''),
 120         quality = d['quality'],
 121         container = cnt,
 122         v_enc = v_enc,
 123         a_enc = a_enc
 124       }
 125       smr[itag] = t
 126     end
 127   end
 128
 129   -- Format list. Combined with the above properties. This list is used
 130   -- for collecting the video resolution.
 131
 132   local fmtl = U.unescape(config['fmt_list'] or error('no match: fmt_list'))
 133   local S = require 'quvi/stream'
 134   local r = {}
 135
 136   for itag,w,h in fmtl:gmatch('(%d+)/(%d+)x(%d+)') do
 137     local smri = smr[itag]
 138     local t = S.stream_new(smri.url)
 139
 140     t.video.encoding = smri.v_enc or ''
 141     t.audio.encoding = smri.a_enc or ''
 142     t.container = smri.container or ''
 143     t.video.height = tonumber(h)
 144     t.video.width = tonumber(w)
 145
 146     -- Do this after we have the video resolution, as the to_id
 147     -- function uses the height property.
 148     t.id = YouTube.to_id(t, itag, smri)
 149
 150     table.insert(r, t)
 151   end
 152
 153   if #r >1 then
 154     YouTube.ch_best(S, r) -- Pick one stream as the 'best' quality.
 155   end
 156
 157   return r
 158 end
 159
 160 -- Picks the stream with the highest video height property
 161 -- as the best in quality.
 162 function YouTube.ch_best(S, t)
 163   local r = t[1] -- Make the first one the 'best' by default.
 164   r.flags.best = true
 165   for _,v in pairs(t) do
 166     if v.video.height > r.video.height then
 167       r = S.swap_best(r, v)
 168     end
 169   end
 170 end
 171
 172 -- Return an ID for a stream.
 173 function YouTube.to_id(t, itag, smri)
 174   return string.format("%s_%s_i%02d_%sp",
 175           smri.quality, t.container, itag, t.video.height)
 176 end
 177
 178 -- vim: set ts=2 sw=2 tw=72 expandtab: