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    1 -------------------------------------------------------------------------
    2              The Xiph.org Foundation's libtheora 1.2
    3 -------------------------------------------------------------------------
    4 
    5 *** What is Theora?
    6 
    7 Theora is Xiph.Org's first publicly released video codec, intended
    8 for use within the Foundation's Ogg multimedia streaming system.
    9 Theora is derived directly from On2's VP3 codec, adds new features
   10 while allow it a longer useful lifetime as an competitive codec.
   11 
   12 The 1.0 release decoder supported all the new features, but the
   13 encoder is nearly identical to the VP3 code.
   14 
   15 The 1.1 release featured a completely rewritten encoder, offering
   16 better performance and compression, and making more complete use
   17 of the format's feature set.
   18 
   19 The 1.2 release features significant additional improvements in
   20 compression and performance. Files produced by newer encoders can
   21 be decoded by earlier releases.
   22 
   23 *** Where is Theora?
   24 
   25 Theora's main site is www.theora.org.  Theora and related libraries
   26 can be gotten from www.theora.org or the main Xiph.Org site at
   27 www.xiph.org.  Development source is kept in an open subversion 
   28 repository, see http://theora.org/svn/ for instructions.
   29 
   30 -------------------------------------------------------------------------
   31 Getting started with the code
   32 -------------------------------------------------------------------------
   33 
   34 *** What do I need to build the source?
   35 
   36 Requirements summary:
   37 
   38   For libtheora:
   39 
   40       libogg 1.1 or newer.
   41 
   42   For example encoder:
   43 
   44       as above,
   45 
   46       libvorbis and libvorbisenc 1.0.1 or newer.
   47       (libvorbis 1.3.1 or newer for 5.1 audio)
   48 
   49   For creating a source distribution package:
   50 
   51       as above,
   52 
   53       Doxygen to build the API documentation,
   54       pdflatex and fig2dev to build the format specification
   55         (transfig package in Ubuntu).
   56 
   57   For the player only:
   58 
   59       as above,
   60 
   61       SDL (Simple Direct media Layer) libraries and headers,
   62       OSS audio driver and development headers.
   63 
   64 The provided build system is the GNU automake/autoconf system, and
   65 the main library, libtheora, should already build smoothly on any
   66 system.  Failure of libtheora to build on a GNU-enabled system is
   67 considered a bug; please report problems to theora-dev@xiph.org.
   68 
   69 Windows build support is included in the win32 directory.
   70 
   71 Project files for Apple XCode are included in the macosx directory.
   72 
   73 There is also a more limited scons build.
   74 
   75 *** How do I use the sample encoder?
   76 
   77 The sample encoder takes raw video in YUV4MPEG2 format, as used by
   78 lavtools, mjpeg-tools and other packages. The encoder expects audio,
   79 if any, in a separate wave WAV file. Try 'encoder_example -h' for a 
   80 complete list of options.
   81 
   82 An easy way to get raw video and audio files is to use MPlayer as an
   83 export utility.  The options " -ao pcm -vo yuv4mpeg " will export a
   84 wav file named audiodump.wav and a YUV video file in the correct
   85 format for encoder_example as stream.yuv.  Be careful when exporting
   86 video alone; MPlayer may drop frames to 'keep up' with the audio
   87 timer.  The example encoder can't properly synchronize input audio and
   88 video file that aren't in sync to begin with.  
   89 
   90 The encoder will also take video or audio on stdin if '-' is specified
   91 as the input file name.
   92 
   93 There is also a 'png2theora' example which accepts a set of image
   94 files in that format.
   95 
   96 *** How do I use the sample player?
   97 
   98 The sample player takes an Ogg file on standard in; the file may be
   99 audio alone, video alone or video with audio.
  100 
  101 *** What other tools are available?
  102 
  103 The programs in the examples directory are intended as tutorial source 
  104 for developers using the library. As such they sacrifice features and 
  105 robustness in the interests of comprehension and should not be 
  106 considered serious applications.
  107 
  108 If you're wanting to just use theora, consider the programs linked
  109 from http://www.theora.org/. There is playback support in a number
  110 of common free players, and plugins for major media frameworks.
  111 Jan Gerber's ffmpeg2theora is an excellent encoding front end.
  112 
  113 -------------------------------------------------------------------------
  114 Troubleshooting the build process
  115 -------------------------------------------------------------------------
  116 
  117 *** Compile error, such as:
  118 
  119 encoder_internal.h:664: parse error before `ogg_uint16_t'
  120 
  121 This means you have version of libogg prior to 1.1. A *complete* new Ogg 
  122 install, libs and headers is needed.
  123 
  124 Also be sure that there aren't multiple copies of Ogg installed in
  125 /usr and /usr/local; an older one might be first on the search path
  126 for libs and headers.
  127 
  128 *** Link error, such as:
  129 
  130 undefined reference to `oggpackB_stream'
  131 
  132 See above; you need libogg 1.1 or later.
  133 
  134 *** Link error, such as:
  135 
  136 undefined reference to `vorbis_granule_time'
  137 
  138 You need libvorbis and libvorbisenc from the 1.0.1 release or later.
  139 
  140 *** Link error, such as:
  141 
  142 /usr/lib/libSDL.a(SDL_esdaudio.lo): In function `ESD_OpenAudio':
  143 SDL_esdaudio.lo(.text+0x25d): undefined reference to `esd_play_stream'
  144 
  145 Be sure to use an SDL that's built to work with OSS.  If you use an
  146 SDL that is also built with ESD and/or ALSA support, it will try to
  147 suck in all those extra libraries at link time too.  That will only
  148 work if the extra libraries are also installed.
  149 
  150 *** Link warning, such as:
  151 
  152 libtool: link: warning: library `/usr/lib/libogg.la' was moved.
  153 libtool: link: warning: library `/usr/lib/libogg.la' was moved.
  154 
  155 Re-run theora/autogen.sh after an Ogg or Vorbis rebuild/reinstall
  156