XiphWiki - User contributions [en]

Bounties

2005-09-14T06:02:53Z

Tesseract:

These are proposed bounty projects, similar to http://gnome.org/bounties/
or the [http://ghostscript.com/article/58.html Ghostscript bug bounty] program.
We don't have the same level of funding but could start a pot with $10-$100 and
let people contribute to specific bounties through paypal.

It would be helpful to list $ amounts which have been donated for each bounty, even if the foundation hasn't decided how much extra (if any) to allocate. --Tesseract

=== OggVorbis 5.1 ===
5.1 Sound encoding in Ogg Vorbis.

There are two steps here. Simple coupling and lowpass for the .1 channel, and a full set of tuned modes.
They should be separate bounties.

:This should be implemented with ambisonics as the internally coupled channels, and then use ambisonic g-format filters for en/dec coding from and to 5.1. This will allow correct playback on many different speaker layouts and an easy path to headphone support.

=== Xiph Quicktime Plugin ===
You have to write a Quicktime Plugin for the Ogg container and the Xiph Codec Family.
[http://qtcomponents.sf.net qtcomponents] provides support for Ogg Vorbis and MNG. This could be used as start.
Xiph Quicktime Plugin has to support encoding/decoding for:
* Ogg Media container
**[http://qtcomponents.sf.net qtcomponents] ''has an operational pluggable API for import, it needs some work to be long term supportable. It does not have a pluggable API for exporting at this time.''
* Support for Chained Ogg Streams
**[http://qtcomponents.sf.net qtcomponents] ''imports chained files as multiple tracks in QuickTime. It does not create chained files during export.''
* Support for Icecast Streams (sending is optional)
**[http://qtcomponents.sf.net qtcomponents] ''implements nothing towards this item. First up is a reverse-engineering effort, as the specifications for a streaming media handler have not been published.''
* Support for Xiph Codec Family: Vorbis, Theora, FLAC, Speex, Writ
**[http://qtcomponents.sf.net qtcomponents] ''has code for Vorbis and Speex (not working at the moment) and there is code at [http://damien.drix.free.fr/qtflac/ Damien Drix's site] for FLAC (decode only).''
It must also be possible to use the Xiph codecs in .mov files in combination with other quicktime codecs.
*[http://qtcomponents.sf.net qtcomponents] ''supports embedding media encoded with Xiph codes into .mov files.''
The plugin should work with at least QuickTime 6.x and 7.x on Mac OS X and Windows. (Mac OS 9 would be nice but probably isn't as important.)

All work must be released under the GPL.

=== Aggressive low-bitrate libvorbis encoding improvements for Vorbis I ===
libvorbis has a lot of room for improvement in all quality/bitrate departments, particularly at the lower quality levels / bitrates. There are many directions to approach this problem from.
To claim this bounty, the following criteria would have to be met:
* A 25%-or-better reduction in bitrate for quality levels -1, 0, 1 on a reasonable testsuite while maintaining qualitative equivilence (or improvement) in community testing.
* No overall qualitative/bitrate regressions in quality levels 2 upwards
* Output ogg files compatible with Vorbis I spec
* Changes under suitable license for re-integration with Xiph.Org libvorbis

=== iPod playback support ===
The [http://ipodlinux.sourceforge.net/ Linux on iPod] project has vorbis decode working (with alternate firmware) at a good fraction of realtime. It should be a small matter of optimization to get it working
for useful playback.

=== FLAC support in libfishsound ===
[http://annodex.net/software/libfishsound/ libfishsound] currently only supports Ogg Vorbis and Ogg Speex. It should be extended to support FLAC to complete the set of Xiph audio codecs.

=== Ogg Vorbis Bitrate Peeling ===
Ogg Vorbis bitrate peeling has been a topic brought up time and again to combat MP3 enthusiasts. But this feature does not actually exist, only the mere possibility abounds. This bounty is set to change that.
The peeler must meet the following criteria:
* Any (optionally transcoded) Vorbis stream can be losslessly re-encoded to a lower quality setting
* Resulting streams would be identical or nearly identical to a stream generated by encoding the original source to the selected quality
* This process is reasonably fast (that is, signifigantly faster than re-encoding from source)
The following must also be accomplished to claim this bounty:
* The encoding libraries must be updated to create peelable Vorbis streams natively
* Old Vorbis streams must be peelable already, or convertable with a utility in order to be made peelable
* If older streams are not natively peelable, old unpeelable Vorbis streams must be identifiable and discernable from peelable streams in such a way as to facilitate transcoding streams from the old format
* All work submitted must be licenced under the GPL or compatible licence (excepting circumstances where other licences conflict) ''[Note: In the GPL-alike case the contribution couldn't be re-integrated with the reference Vorbis encoder/decoder... do we need to stipulate a libvorbis-compatible license like the BSD/X11?]''

Main Page

2005-06-14T12:39:45Z

Tesseract: delete spam

= Projects/Formats =

In an effort to bring open-source ideals to the world of multimedia The Xiph.org Foundation ([[XiphOrg]]) develops a multitude of amazing products.

== Container Formats ==

* [[Ogg]]: Media container. This is our native format and the recommeded container for Xiph codecs.
* [[OggSkeleton]]: Skeleton information on all logical content bitstreams in Ogg

* [[SpeexRTP]]: RTP payload format for voice
* [[VorbisRTP]]: RTP payload format for general audio
* [[TheoraRTP]]: RTP payload format for video

== Codecs ==

* [[Vorbis]]: Audio codec
* [[Tremor]]: Fixed-point decoder
* [[Theora]]: Video codec
* [[FLAC]]: Free Lossless Audio Codec
* [[Speex]]: Speech codec
* [[Ogg Writ]]: Text phrase codec (e.g. subtitles)
* [[Metadata]]: Arbitrary metadata stream format (vapourware so far)
* [[OggMNG]]: A mapping for encapsulating the MNG animation format in Ogg

== Software for distributing media ==

* [[Icecast]]: Streaming server
* [[Ices]]: Source client for Icecast servers
* [[IceShare]]: P2P content distribution

= Demonstrations =

Want to hear Xiph in action? These projects are using our codecs, formats, or libraries.

* [[VorbisStreams]]: Stations streaming with the Vorbis codec
* [[Games that use Vorbis]]: Games using the Vorbis codec for music or sound effects
* [[VorbisHardware]]: Hardware players using the Vorbis codec
* [http://www.tversity.com TVersity Media Server]: A UPNP/AV compliant media server that uses the Ogg Vorbis libraries to transcode audio files to the Ogg Vorbis format.

= Project management =

* [[MonthlyMeeting]]
* [[MailingLists]]
* [[Bounties]]
* [[HyperFish]]

= Wiki internal =
* [[Sandbox]]: Testbed for testing editing skills.
* [[Translations]]: What about some translation work

Bounties

2005-05-13T13:25:13Z

Tesseract: /* Xiph Quicktime Plugin */

These are proposed bounty projects, similar to http://gnome.org/bounties/
or the [http://ghostscript.com/article/58.html Ghostscript bug bounty] program.
We don't have the same level of funding but could start a pot with $10-$100 and
let people contribute to specific bounties through paypal.

=== OggVorbis 5.1 ===
5.1 Sound encoding in Ogg Vorbis.

There are two steps here. Simple coupling and lowpass for the .1 channel, and a full set of tuned modes.
They should be separate bounties.

=== Xiph Quicktime Plugin ===
You have to write a Quicktime Plugin for the Ogg container and the Xiph Codec Family.
[http://qtcomponents.sf.net qtcomponents] provides support for Ogg Vorbis and MNG. This could be used as start.
Xiph Quicktime Plugin has to support encoding/decoding for:
* Ogg Media container
**[http://qtcomponents.sf.net qtcomponents] ''has an operational pluggable API for import, it needs some work to be long term supportable. It does not have a pluggable API for exporting at this time.''
* Support for Chained Ogg Streams
**[http://qtcomponents.sf.net qtcomponents] ''imports chained files as multiple tracks in QuickTime. It does not create chained files during export.''
* Support for Icecast Streams (sending is optional)
**[http://qtcomponents.sf.net qtcomponents] ''implements nothing towards this item. First up is a reverse-engineering effort, as the specifications for a streaming media handler have not been published.''
* Support for Xiph Codec Family: Vorbis, Theora, FLAC, Speex, Writ
**[http://qtcomponents.sf.net qtcomponents] ''has code for Vorbis and Speex (not working at the moment) and there is code at [http://damien.drix.free.fr/qtflac/ Damien Drix's site] for FLAC (decode only).''
It must also be possible to use the Xiph codecs in .mov files in combination with other quicktime codecs.
*[http://qtcomponents.sf.net qtcomponents] ''supports embedding media encoded with Xiph codes into .mov files.''
The plugin should work with at least QuickTime 6.x and 7.x on Mac OS X and Windows. (Mac OS 9 would be nice but probably isn't as important.)

=== Aggressive low-bitrate libvorbis encoding improvements for Vorbis I ===
libvorbis has a lot of room for improvement in all quality/bitrate departments, particularly at the lower quality levels / bitrates. There are many directions to approach this problem from.
To claim this bounty, the following criteria would have to be met:
* A 25%-or-better reduction in bitrate for quality levels -1, 0, 1 on a reasonable testsuite while maintaining qualitative equivilence (or improvement) in community testing.
* No overall qualitative/bitrate regressions in quality levels 2 upwards
* Output ogg files compatible with Vorbis I spec
* Changes under suitable license for re-integration with Xiph.Org libvorbis

=== iPod playback support ===
The [http://ipodlinux.sourceforge.net/ Linux on iPod] project has vorbis decode working (with alternate firmware) at a good fraction of realtime. It should be a small matter of optimization to get it working
for useful playback.

=== FLAC support in libfishsound ===
[http://annodex.net/software/libfishsound/ libfishsound] currently only supports Ogg Vorbis and Ogg Speex. It should be extended to support FLAC to complete the set of Xiph audio codecs.

=== Ogg Vorbis Bitrate Peeling ===
Ogg Vorbis bitrate peeling has been a topic brought up time and again to combat MP3 enthusiasts. But this feature does not actually exist, only the mere possibility abounds. This bounty is set to change that.
The peeler must meet the following criteria:
* Any (optionally transcoded) Vorbis stream can be losslessly re-encoded to a lower quality setting
* Resulting streams would be identical or nearly identical to a stream generated by encoding the original source to the selected quality
* This process is reasonably fast (that is, signifigantly faster than re-encoding from source)
The following must also be accomplished to claim this bounty:
* The encoding libraries must be updated to create peelable Vorbis streams natively
* Old Vorbis streams must be peelable already, or convertable with a utility in order to be made peelable
* If older streams are not natively peelable, old unpeelable Vorbis streams must be identifiable and discernable from peelable streams in such a way as to facilitate transcoding streams from the old format
* All work submitted must be licenced under the GPL or compatible licence (excepting circumstances where other licences conflict) ''[Note: In the GPL-alike case the contribution couldn't be re-integrated with the reference Vorbis encoder/decoder... do we need to stipulate a libvorbis-compatible license like the BSD/X11?]''