Fig2dev is a set of tools for creating TeX documents with graphics which are portable, in the sense that they can be printed in a wide variety of environments.

Xfig is an interactive drawing tool which runs under X Window System. In xfig, figures may be drawn using objects such as circles, boxes, lines, spline curves, text, etc. It is also possible to import images in formats such as GIF, JPEG, EPSF (PostScript), etc. Those objects can be created, deleted, moved or modified. Attributes such as colors or line styles can be selected in various ways. For text, 35 fonts are available.

FLAC stands for Free Lossless Audio Codec, an audio format that is lossless, meaning that audio is compressed in FLAC without any loss in quality.

Libshout is a library for communicating with and sending data to an icecast server. It handles the socket connection, the timing of the data, and prevents bad data from getting to the icecast server.

Opus is a royalty-free, highly versatile audio codec. Opus-tools provide command line utilities for creating, inspecting and decoding .opus files.

The libogg library manipulates the ogg multimedia container format, which encapsulates raw compressed data and allows the interleaving of audio and video data. In addition to encapsulation and interleaving of multiple data streams, ogg provides packet framing, error detection, and periodic timestamps for seeking.

Icecast is a streaming media server which currently supports Ogg (Vorbis and Theora), Opus, WebM and MP3 audio streams. It can be used to create an Internet radio station or a privately running jukebox and many things in between.

Opus is a totally open, royalty-free, highly versatile audio codec. Opus is unmatched for interactive speech and music transmission over the Internet, but is also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716 which incorporated technology from Skype's SILK codec and Xiph.Org's CELT codec.

Libao is a cross-platform audio library that allows programs to output audio using a simple API on a wide variety of platforms. It currently supports:

1. Null output (handy for testing without a sound device),

2. WAV files,

3. AU files,

4. RAW files,

5. OSS (Open Sound System, used on Linux and FreeBSD),

6. ALSA (Advanced Linux Sound Architecture),

7. aRts (Analog RealTime Synth, used by KDE),

8. PulseAudio (next generation GNOME sound server),

9. esd (EsounD or Enlightened Sound Daemon),

10. Mac OS X,

11. Windows (98 and later),

12. AIX,

13. Sun/NetBSD/OpenBSD,

14. IRIX,

15. NAS (Network Audio Server),

16. RoarAudio (Modern, multi-OS, networked Sound System),

17. OpenBSD's sndio.

GNU Speex is a patent-free audio compression codec specially designed for speech. It is well-adapted to internet applications, such as VoIP. It features compression of different bands in the same bitstream, intensity stereo encoding, and voice activity detection.

The libopusenc libraries provide a high-level API for encoding Opus files and streams.

The libvorbis library implements the ogg vorbis audio format, a fully open, non-proprietary, patent-and-royalty-free, general-purpose compressed audio format for mid to high quality (8kHz-48.0kHz, 16+ bit, polyphonic) audio and music at fixed and variable bitrates from 16 to 128 kbps/channel.

SpeexDSP is a DSP (Digital Signal Processing) library based on work from the speex codec.

Kate is an overlay codec, originally designed for karaoke and text, that can be multiplixed in Ogg. Text and images can be carried by a Kate stream, and animated. Most of the time, this would be multiplexed with audio/video to carry subtitles, song lyrics (with or without karaoke data), etc., but doesn't have to be.

Series of curves (splines, segments, etc.) may be attached to various properties (text position, font size, etc.) to create animated overlays. This allows scrolling or fading text to be defined. This can even be used to draw arbitrary shapes, so hand drawing can also be represented by a Kate stream.

The libtheora library implements the ogg theora video format, a fully open, non-proprietary, patent-and-royalty-free, general-purpose compressed video format.

The opusfile library provides seeking, decode, and playback of Opus streams in the Ogg container (.opus files) including over http(s) on posix and windows systems.

RNNoise is a noise suppression library based on a recurrent neural network. The algorithm is described in Jean-Marc Valin's paper A Hybrid DSP/Deep Learning Approach to Real-Time Full-Band Speech Enhancement.

Ogg vorbis is a non-proprietary, patent-and-royalty-free, general-purpose compressed audio format.

The package vorbis-tools contains ogg123, an ogg vorbis command line audio player; oggenc, the ogg vorbis encoder; oggdec, a simple, portable command line decoder (to wav and raw); ogginfo, to obtain information (tags, bitrate, length, etc.) about an ogg vorbis file.

XML::TokeParser provides a procedural ("pull mode") interface to XML::Parser in much the same way that Gisle Aas' HTML::TokeParser provides a procedural interface to HTML::Parser. XML::TokeParser splits its XML input up into "tokens", each corresponding to an XML::Parser event.

The xmlschema library is an implementation of XML Schema for Python. It has full support for the XSD 1.0 and 1.1 standards, an XPath-based API for finding schema's elements and attributes; and can encode and decode XML data to JSON and other formats.

XML::Compile can be used to translate a Perl data-structure into XML or XML into a Perl data-structure, both directions under rigid control by a schema.

This package provides methods to cache compiled XML translators.

The XML Security Library is a C library based on Libxml2. It supports XML security standards such as XML Signature, XML Encryption, Canonical XML (part of Libxml2) and Exclusive Canonical XML (part of Libxml2).

The conventional models for parsing XML are either DOM (a data structure representing the entire document tree is created) or SAX (callbacks are issued for each element in the XML).

XML grammar is recursive - so it's nice to be able to write recursive parsers for it. XML::Descent allows such parsers to be created.