Ogg
What is Ogg
The name ‘Ogg’ refers to the file format which can multiplex a number of separate independent free and open source codecs for audio, video, text (such as subtitles), and metadata. The term ‘Ogg’ is often used to refer to audio file format Ogg Vorbis, that is, Vorbis-encoded audio in the Ogg container. Other prominent Xiph codecs that are often encapsulated in Ogg are the video codec Theora, and the human speech audio compression format Speex.
Previously, the .ogg file extension was used for any content distributed within Ogg, but as of 2007, the Xiph.Org Foundation requests that .ogg be used only for Vorbis due to backwards-compatibility concerns. The Xiph.Org Foundation decided to create a new set of file extensions and media types to describe different types of content such as .oga for audio, .ogv for video (including Theora), and .ogx for applications.1
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Because the format is free, Ogg's various codecs have been incorporated into a number of different free and proprietary media players, both commercial and non-commercial, as well as portable media players from different manufacturers.This article contains content from a Wikipedia article which is licensed under the GNU Free Documentation License.
Why OGG?
OGG is free (as in beer) and OGG is free (as in speech). This fits in with the OLPC's goals far better than the proprietary and sometimes costly .wma or .mp3. OGG is also highly compressible, meaning you can achieve high quality at the same or smaller filesizes. OGG is also very well supported in Gstreamer which most of the media on the XO is ran by.
What Flavor? Theora, Vorbis, FLAC, Speex ...
OGG is only a container format, there are various types of media that can be stored inside of a .ogg file. Video is encoded in Theora, general audio (music) is encoded in Vorbis, human speech is recorded in Speex and lossless audio is encoded in FLAC.
Theora
Vorbis
Speex
In particular, the ability to record OGG/Speex files would allow the OLPC to be used for taking voice notes of classroom sessions. These can be used in two ways. One is for the student to review again at home if they have had difficulty in understanding it all the first time. The second is to send these files to students who were unable to participate in the classroom. These may be students who are ill or they may be students who live too far from the class to travel there daily. In such situations there are generally adults who are able to travel back and forth on a daily basis using some means of transportation (animal-drawn cart, bicycle, scooter).
Speex recording would also allow students to create their own audiobooks ala Librivox. Speex would also be an ideal vocal track for stop motion Animation.
FLAC
The OLPC project needs to leverage these travelers, following the example of the Motoman project, to distribute content more widely and OGG recording capability will help in that effort.