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About .MOGG File Format

A .MOGG file is basically a variant of the “OggVorbis” file format.

According to Wikipedia,

Ogg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format state that it is unrestricted by software patents[4] and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.

The Ogg container format can multiplex a number of independent streams for audio, video, text (such as subtitles), and metadata.

Vorbis is a free software / open source project headed by the Xiph.Org Foundation (formerly Xiphophorus company). The project produces an audio format specification and software implementation (codec) for lossy audio compression. Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis.

Vorbis is a continuation of audio compression development started in 1993 by Chris Montgomery. Intensive development began following a September 1998 letter from the Fraunhofer Society announcing plans to charge licensing fees for the MP3 audio format. Vorbis project started as part of the Xiphophorus company’s Ogg project (also known as OggSquish multimedia project). Chris Montgomery began work on the project and was assisted by a growing number of other developers. They continued refining the source code until the Vorbis file format was frozen for 1.0 in May 2000 and a stable version (1.0) of the reference software was released on July 19, 2002.

The Xiph.Org Foundation maintains a reference implementation, libvorbis, the latest official version of which is 1.3.2, released on November 1, 2010. There are also some fine-tuned forks, most notably aoTuV, that offer better audio quality, particularly at low bitrates. These improvements are periodically merged back into the reference codebase.

The Vorbis format has proven popular among supporters of free software. They argue that its higher fidelity and completely free nature, unencumbered by patents, make it a well-suited replacement for patented and restricted formats like MP3.

Vorbis has different uses for consumer products. Many video game titles such as 18 Wheels of Steel, Halo, Unreal Tournament 2004, Unreal Tournament 3, Mafia: The City of Lost Heaven, Jets ‘n’ guns, Grand Theft Auto: San Andreas, Crimsonland, Devil May Cry 3, Live For Speed and Guitar Hero: On Tour store in-game audio as Vorbis. Popular software players support Vorbis playback either natively or through an external plugin. A number of Web sites, including Wikipedia, use it. Others include Jamendo and Mindawn, as well as several national radio stations like JazzRadio, Absolute Radio, NPR, Radio New Zealand and Deutschlandradio. The Spotify audio streaming service uses Vorbis for its audio streams.

Quality: Codec comparisons

For many applications, Vorbis has clear advantages over other lossy audio codecs in that it is patent-free and has free and open-source implementations and therefore is free to use, implement, or modify as one sees fit, yet produces smaller files than most other codecs at equivalent or higher quality while retaining computational complexity comparable to other MDCT codecs such as AAC or Windows Media Audio.

Listening tests have attempted to find the best quality lossy audio codecs at certain bitrates. Some conclusions made by listening tests:

* Low bitrate (less than 64 kbit/s): the most recent public multiformat test at 48 kbit/s shows that aoTuV Vorbis has a better quality than WMA and LC-AAC, the same quality as WMA Professional, and a lower quality than HE-AAC.

* Mid to low bitrates (less than 128 kbit/s down to 64 kbit/s): private tests at 80 kbit/s and 96 kbit/s shows that aoTuV Vorbis has a better quality than other lossy audio codecs (LC-AAC, HE-AAC, MP3, MPC, WMA).

* High bitrates (more than 128 kbit/s): most people do not hear significant differences. However, trained listeners can often hear significant differences between codecs at identical bitrates, and aoTuV Vorbis performs better than LC-AAC, MP3, and MPC.

Many of these results, however, are difficult to keep up to date due to the ever-evolving nature of the codecs.

Listening tests

Listening tests are normally carried out as ABX tests, i.e., the listener has to identify an unknown sample X as being A or B, with A (the original) and B (the encoded version) available for reference. The outcome of a test must be statistically significant. This setup ensures that the listener is not biased by his/her expectations, and that the outcome is very unlikely to be the result of chance. If sample X can be identified reliably, the listener can assign a score as a subjective judgement of the quality. Otherwise, the encoded version is considered to be transparent.

* 2005, July comparison – AAC vs MP3 vs Vorbis vs WMA at 80 kbit/s. States that aoTuV beta 4 is the best encoder for either classical or various music in this bitrate, and that its quality is comparable to the LAME ABR MP3 at 128 kbit/s.

* 2005, August comparison – AAC vs MP3 vs Vorbis vs WMA at 96 kbit/s. States that aoTuV beta 4 and AAC are tied as the best encoders for classical music in this bitrate, while aoTuV beta 4 is the best encoder for pop music, even better than LAME at 128 kbit/s.[30]

* 2005, August comparison – MPC vs Vorbis vs MP3 vs AAC at 180 kbit/s. An audiophile listening test, which states that, for classical music, aoTuV beta 4 has 93% percent probability of being the best encoder, tied with MPC. MPC is tied with both Vorbis, in the first place, and LAME in the second.


One response

  1. samenezes

    Excelent work on all pages.

    It is the one, or the only, complete reference about Mogg files and its production and concepts.


    Artur Sá Menezes

    May 11, 2011 at 3:54 pm

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