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OGG Vorbis FAQ

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.

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 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 supported by many portable players and mobile phonws running Symbian OS. A list of suported hardware and software may be found at OggHelp.com.

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: www.vorbis.com