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2 The Xiph.org Foundation's libtheora 1.0alpha7 release
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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; Currently the two are
10 nearly identical, varying only in encapsulating decoder tables in the
11 bitstream headers, but Theora will make use of this extra freedom
12 in the future to improve over what is possible with VP3.
16 Theora's main site is www.theora.org. Theora and related libraries
17 can be gotten from www.theora.org or the main Xiph.Org site at
18 www.xiph.org. Development source is kept in an open subversion
19 repository, see http://theora.org/svn.html for instructions.
21 *** What is the goal of this alpha release?
23 The Theora bitstream format was frozen after the alpha3 release. This
24 means that files produced by the alpha3 encoder will always be playable
25 according to the Theora I specification.
27 Traditionally alpha mean proof of concept, not a production-ready
28 release. However the code is very robust, ready for and indeed
31 The purpose of this release is to provide an updated testing base for
32 those interested in theora and to dissiminate more widely the changes
33 we've made since the last alpha release. These include some helper
34 utility functions, a draft format specification and api documentation
35 located in the doc directory.
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38 Getting started with the code
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41 *** What do I need to build the source?
48 (there is optional support for libogg2, unreleased at this time)
54 libvorbis and libvorbisenc 1.0.1 or newer.
60 SDL (Simple Direct media Layer) libraries and headers
62 OSS audio driver and development headers
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.
69 Some windows build support is included in the win32 directory.
71 *** How do I use the sample encoder?
73 The sample encoder takes raw video in YUV4MPEG2 format, as used by
74 lavtools, mjpeg-tools and other packages. Snatch and MPlayer version
75 0.90 and later can also export in YUV4MPEG format (more on this
76 later). The encoder take audio as WAV files. encoder_example -h
77 lists options accepted by the encoder.
79 An easy way to get raw video and audio files is to use MPlayer as an
80 export utility. The options " -ao pcm -vo yuv4mpeg " will export a
81 wav file named audiodump.wav and a YUV video file in the correct
82 format for encoder_example as stream.yuv. Be careful when exporting
83 video alone; MPlayer may drop frames to 'keep up' with the audio
84 timer. The example encoder can't properly synchronize input audio and
85 video file that aren't in sync to begin with.
87 The encoder will also take video or audio on stdin if '-' is specified
88 as the input file name.
90 *** How do I use the sample player?
92 The sample player takes an Ogg file on standard in; the file may be
93 audio alone, video alone or video with audio.
95 *** What other tools are available?
97 If you're wanting to just use theora, consider the programs linked
98 from http://www.theora.org/. There is playback support in a number
99 of common free players, and Jan Gerber's ffmpeg2theora is an excellent
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103 Troubleshooting the build process
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106 *** Compile error, such as:
108 encoder_internal.h:664: parse error before `ogg_uint16_t'
110 This means you have version of libogg prior to 1.1. A *complete* new Ogg
111 install, libs and headers, from a new release or CVS is needed. Don't
112 forget to re-reun autogen.sh so that autoconf sucks in the new type
115 Also be sure that there aren't multiple copies of Ogg installed in
116 /usr and /usr/local; an older one might be first on the search path
117 for libs and headers.
119 *** Link error, such as:
121 undefined reference to `oggpackB_stream'
123 See above; you need libogg 1.1 or later.
125 *** Link error, such as:
127 undefined reference to `vorbis_granule_time'
129 You need libvorbis and libvorbisenc from the 1.0.1 release or later.
131 *** Link error, such as:
133 /usr/lib/libSDL.a(SDL_esdaudio.lo): In function `ESD_OpenAudio':
134 SDL_esdaudio.lo(.text+0x25d): undefined reference to `esd_play_stream'
136 Be sure to use an SDL that's built to work with OSS. If you use an
137 SDL that is also built with ESD and/or ALSA support, it will try to
138 suck in all those extra libraries at link time too. That will only
139 work if the extra libraries are also installed.
141 *** Link warning, such as:
143 libtool: link: warning: library `/usr/lib/libogg.la' was moved.
144 libtool: link: warning: library `/usr/lib/libogg.la' was moved.
146 Re-run theora/autogen.sh after an Ogg or Vorbis rebuild/reinstall