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What is Ogg Vorbis?
Ogg Vorbis is a new audio compression format. It is roughly comparable to other
formats used to store and play digital music, such as MP3, VQF, AAC, and other
digital audio formats. It is different from these other formats because it is
completely free, open, and unpatented.
What do all the names mean?
Vorbis is the name for the specific audio compression scheme used to create Ogg
Vorbis files. It is part of the Ogg project, which is a blanket project designed
to create a fully open multimedia system. Right now, Ogg Vorbis is the only
functional part of the Ogg project which is anywhere near completion.
Where do the names come from? What does the logo mean?
Xiph.org has a page explaining the sources and meanings of the names and logos.
What is the file extension for Ogg Vorbis?
Since it is part of the Ogg project, Vorbis files have the extension .ogg.
Does Vorbis completely replace MP3, or is it just a complementary codec?
Ogg Vorbis has been designed to completely replace all proprietary, patented
audio formats. That means that you can encode all your music or audio content in
Vorbis and never look back.
When will Ogg Vorbis be done?
There are stable reference implementations available now, and the file
format has been finished for some time. A Vorbis file created today will still
be compatible with future decoders for years to come. The format has been
designed to be flexible, so that the developers can continue to improve file
size and sound quality without "breaking" older encoders and players.
I'm an artist. Why should I be interested?
There are a couple of reasons:
Although not all artists realize it, MP3 is what is known as a "lossy" format.
Thus, much of the sound data is removed when MP3 files are created. This results
in a file with inferior sound quality to a CD. Vorbis is also a "lossy" format,
but uses superior acoustic models to reduce the damage. Thus, music released in
Vorbis will sound better than a comparably sized MP3 file.
Also, artists should be concerned about licensing terms for formats. If you
decide to sell your music in MP3 format, you are responsible for paying
Fraunhofer a percentage of each sale because you are using their patents. Vorbis
is patent and license-free, so you will never need to pay anyone in order to
sell, give away, or stream your own music.
I'm a music fan. Why should I be interested?
For one, Vorbis provides a high-quality format for you to
listen to your music. For a given file size, Vorbis sounds better than MP3, and
is getting better as development continues. Vorbis already enjoys widespread
player support and should be compatible with several major hardware players
soon. With Vorbis, you can listen to your music with higher quality in less
space. Also, using Vorbis means your player and encoder choices aren't bound by
licensing terms. Right now, you can only choose from a few encoders to create
your MP3 files, because most companies won't or can't pay the licensing terms
for encoders. Using Vorbis lets you choose from a wide variety of encoders.
I'm a developer. Why should I be interested?
If you develop hardware or software audio players, you cannot
distribute your work without being affected by proprietary audio patent
licensing terms. With Vorbis, you can create hardware or software products to
encode or decode music files without restrictions, royalty payments, or limits
on distribution. Vorbis also provides a flexible, high-quality format that is of
great interest to all the audio geeks out there. For more developer information,
please refer to our developer site.
I run a music company. Why should I be interested?
Music companies should be very interested in the Ogg Vorbis
format. Other technologies require large financial investments to get started,
but Vorbis offers a unique platform that is easily reachable for growing
companies and a money saver for established businesses. Because of its wide
player support and its open nature, your customers and clients will not be
plagued by incompatibilities and they will appreciate the higher sound quality
as well.
What licensing applies to the Ogg Vorbis format?
The Ogg Vorbis specification is in the public domain. It is completely free
for commercial or noncommercial use. That means that commercial developers may
independently write Ogg Vorbis software which is compatible with the
specification for no charge and without restrictions of any kind. However,
developers that wish to use the open source software we have written must adhere
to certain rules.
What licensing applies to the included Ogg Vorbis software?
The bundled Ogg Vorbis utility software is released under the terms of the
GNU GPL, or GNU General Public License. The details can be found at www.gnu.org.
The libraries and SDKs are released under the more business-friendly BSD
license. Please note that developers are still free to use the specification to
independently write closed-source implementations of Ogg Vorbis which are not
bound by these licenses.
We make commercial, closed source software. Can I use Ogg Vorbis at all? What
licensing do I need to pay?
Again, there are no licensing fees for ANY use of the Ogg Vorbis specification.
As a commercial developer, you are free to create and sell (or give away) open
or closed source implementations of Vorbis encoders, decoders, or other tools.
However, if you use our software rather than writing an independent
implementation, you must respect the terms of the license. Our libraries
(available under the BSD license) can be used whole or in part by closed source
applications.
Are there licensing fees for distributing, selling, or streaming media in the
Ogg Vorbis format like there are in other formats, such as MP3?
No.
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Software currently available that offers OGG converter
functionality:
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I've heard that Vorbis is a "lossy" codec. What does this mean?
There are two broad classes of compression algorithms: lossless and lossy.
Lossless compression algorithms produce compressed data that can be decoded to
output that is identical to the original. Zip is a very common example of a
lossless compression format. FLAC is a lossless compression format that is
specifically designed for audio.
The other type of compression algorithm is called lossy. This form of
compression is very popular with multimedia data, like pictures, movies, and
sound. Since these types of information are perceived by humans with imperfect
senses, the original data does not have to be reproduced exactly. Some of the
information in the original file can actually be discarded because we wouldn't
notice it even if it was there. Lossy codecs can achieve much higher compression
than lossless codecs by intelligently discarding unneeded information. In most
cases, some loss of quality can be tolerated, so even more data can be
discarded, further increasing compression. MP3, RealAudio, and Vorbis all use
lossy audio compression. This means that a Vorbis file, for example, will decode
to a WAV file that is different than the original. The differences may or may
not be noticable, depending upon the quality selected during compression.
Will Ogg Vorbis audio quality improve?
Yes. Vorbis has a flexible format which allows significant tuning of sound
quality and training of the algorithms even after the file format is frozen.
Vorbis sounds very good today, and will continue to sound better every day.
Why is Ogg Vorbis better than the other "New MP3" codecs that are available?
Vorbis sounds better. Vorbis is open, so you're free to use it on your favorite
platform. Vorbis doesn't have intellectual property restrictions to get in the
way. And Vorbis doesn't just try to sound better, it tries to do things
fundamentally better in all the ways that it can.
Can I convert my MP3 collection to the Ogg Vorbis format?
You can convert any audio format to Ogg Vorbis. However, converting from one
lossy format, like MP3, to another lossy format, like Vorbis, is generally a bad
idea. Both MP3 and Vorbis encoders achieve high compression ratios by throwing
away parts of the audio waveform that you probably won't hear. However, the MP3
and Vorbis codecs are very different, so they each will throw away different
parts of the audio, although there certainly is some overlap. Converting a MP3
to Vorbis involves decoding the MP3 file back to an uncompressed format, like
WAV, and recompressing it using the Ogg Vorbis encoder. The decoded MP3 will be
missing the parts of the original audio that the MP3 encoder chose to discard.
The Ogg Vorbis encoder will then discard other audio components when it
compresses the data. At best, the result will be an Ogg file that sounds the
same as your original MP3, but it is most likely that the resulting file will
sound worse than your original MP3. In no case will you get a file that sounds
better than the original MP3.
Since many music players can play both MP3 and Ogg files, there is no reason
that you should have to switch all of your files to one format or the other. If
you like Ogg Vorbis, then we would encourage you to use it when you encode from
original, lossless audio sources (like CDs). When encoding from originals, you
will find that you can make Ogg files that are both smaller and better quality
than MP3.
(If you must absolutely must convert from MP3 to Ogg, there are several
conversion scripts available on Freshmeat.)
What does the "Quality" setting mean?
Beginning with libvorbis 1.0rc3, audio quality is no longer measured in kilobits
per second, but on an arbitrary scale of 0 to 10, called "quality." This change
in terminology was brought about by a tuning of the variable-bitrate algorithm
that produces better sound quality for a given average bitrate, but which does
not adhere as strictly to that average as a target.
This new scale of measurement is not tied to a quantifiable characteristic of
the stream, like bitrate, so it's a fairly subjective metric, but provides a
more stable basis of comparison to other codecs and is relatively future-proof.
As Segher Boessenkool <segher@xiph.org> explained, "if you upgrade to a new
vorbis encoder, and you keep the same quality setting, you will get smaller
files which sound the same. If you keep the same nominal bitrate, you get about
the same size files, which sound somewhat better." The former behavior is the
aim of the quality metric, so encoding to a target bitrate is now officially
deprecated for all uses except streaming over bandwidth-critical connections.
For now, quality 0 is roughly equivalent to 64kbps average, 5 is roughly
160kbps, and 10 gives about 400kbps. Most people seeking very-near-CD-quality
audio encode at a quality of 5 or, for lossless stereo coupling, 6. The default
setting is quality 3, which at approximately 110kbps gives a smaller filesize
and significantly better fidelity than .mp3 compression at 128kbps.
How does Vorbis fare for speech compression?
It works well, but is generally not the optimal solution. Vorbis is designed
for the compression of music and general purpose audio. Special purpose codecs
can achieve much greater compression of speech than Vorbis. Vorbis also tends to
have a latency that is too high for telephony, a common use of speech codecs.
Read the Speech Coding and Compression FAQ for more details. Those looking for
an open-source, patent-free speech codec should take a look at Speex.
How big are Ogg Vorbis files? How do they compare to MP3 files at similar
bitrates?
Two files encoded at the same bitrate, will always be the same size, if they
are both encoded with CBR (Constant Bitrate). The current Vorbis encoder can
encode files in VBR (Variable Bitrate) which can produce smaller files with
better quality, since it doesn't have to waste data for audio that is easy to
encode. Files produced by the Vorbis encoder at the default quality will be
similar in size to 110kbps MP3 files, but will sound better.
What is the maximum bitrate at which Vorbis can be encoded?
Theoretically, there isn't one. Vorbis is tuned for bitrates of 16kbps to
128kbps PER CHANNEL. But there's nothing in the spec that says you can't encode
a file at 512kbps or 8kbps. The current encoder supports the following bitrates:
64-500kbps stereo and 32-256kbps mono (at 44.1kHz sampling rate). Lower bitrates
will be officially available in future versions.
Does Ogg Vorbis have the capability to show song titles and artist
information when the file is played or streamed?
Yes, Vorbis includes a flexible, complete comment field for song and artist
info, as well as other track data. The official encoder, oggenc, allows you to
enter comment info at encode-time. Other 3rd-party encoding tools also let you
enter or edit track data.
How fast are the encoders/decoders?
Right now the encoder is about as fast as most commercial audio encoders (and
about twice as fast as beta 3), but not nearly as fast as some others. Since we
are using unoptimized beta code, this is to be expected. As the vorbis tools
mature they will become faster. The decoding is roughly the same complexity as
MP3 decoding, and once the Vorbis decoding tools are optimized, they should
decode at similar speeds. Decoding speed has increased 3-4x over the first beta
already, after the first stage of optimization.
Where's video?
If you're interested in our progress on a video codec, check out Theora at
http://www.theora.org. Theora's 1.0 release is scheduled for Summer of 2003.
What about streaming in Ogg Vorbis format?
Streaming is an important component of Vorbis. The format has been designed from
the ground-up to be easily streamable. The designers of Vorbis are working
alongside the creators of Icecast streaming media software to make Icecast
Vorbis-compatible. We are also working on player support for streaming Ogg
files. Streaming Ogg files from the web will be supported by the player plugins
at the 1.0 Vorbis release.
What software and hardware support Ogg Vorbis?
Ogg Vorbis encoding and/or playback is now native in a wide variety of popular
software. It's included in popular players such as WinAmp, Sonique, FreeAmp for
Windows, and Unsanity Echo for MacOS. It's also supported in popular audio
applications such as CDex, Siren Jukebox, and GoldWave. For a more complete
list, refer to our software page. Ogg Vorbis is not supported by any
publicly-available hardware yet, but portable playback is possible for Sharp
Zaurus owners by purchasing tkcPlayer software from TheKompany.
Can I bundle Vorbis and another media type (like text lyrics or pictures) in
the same file?
Yes. The Ogg container format was designed to allow different media types to be
multiplexed together. In the future, Ogg movies will most likely consist of a
Vorbis audio track and a video track (using Tarkin, VP3 or some other video
codec) inside of a single Ogg file. Some preliminary work has been done to put
MNG and MIDI content into Ogg files as well. Experimental code is available in
the ogg-tools module in the Xiph.org CVS repository. Programmers working on such
extensions can discuss issues and questions on the vorbis-dev mailing list.
What other unique features does Ogg Vorbis have?
Vorbis has a well defined comment header that is easy to use and extensible and
obviates the need for clunky hacks like ID3 tags. Vorbis has bitrate scaling - a
feature that lets you adjust the bitrate of a Vorbis file or stream without
reencoding; just chop the packets up in the sizes you want them. Vorbis files
can be sliced and edited with sample granularity. Vorbis has support for many
channels, not just 1 or 2. Vorbis files can be logically chained together.
Source: http://www.vorbis.com
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