Calibre is an e-book library management application, viewer and editor. It's also commonly used for e-book file format conversion and syncing to reader devices. Calibre also simplifies downloading news from the web and converting them into e-book form, and can act as content server for online access to your book collection.
Ardour is an audio processing and editing application. It integrates broad hardware support, JACK and ALSA backends, flexible recording features, multi-channel nesting, import and exporting various file formats, comes with ready to use samples from freesound.org. It has a pretty editing UI, mixing, routing, monitoring, panning. Ardour allows non-destructive and non-linear editing, can be used for augmenting audio layers in video files even. And comes with many effect, input and output plugins. I
The abcMIDI suite consists of programs for turning ABC music files into MIDI and vice versa, typesetting them as PostScript files, and manipulate them in several ways.
abcm2ps is a command-line program that converts ABC music notation files to sheet music in PostScript or SVG format.
Dateutils are a bunch of tools that revolve around fiddling with dates and times in the command line, with a strong focus on use cases that arise when dealing with large amounts of financial data. Their target market is shell scripts that need date calculations or calendar conversions, and as such they are highly pipe-able and modeled after their well-known cousins (e.g. dtest vs. test, or dgrep vs. grep).
HandBrake is a video file conversion tool. It supports nearly all formats, can transcode media files and codecs for various platforms, players and devices (includes a user-friendly target list to select from). It has an uncomplicated interface and is available cross-platform.
FFmpeg is the leading framework for decoding, encoding, transcoding, muxing, demuxing, streaming, filtering and playing pretty much any media format. It supports widespread and standardized, proprietary and fringe file formats and encodings. It's comprised of the ffmpeg, ffserver, ffplay and ffprobe utilities. But also provides libavcodec, libavutil, libavformat, libavfilter, libavdevice, libswscale and libswresample for application use. Its primary development attention is on security.
Frei0r is a minimalistic plugin API for video effects. The main emphasis is on simplicity for an API that rounds up the most common video effects into simple filters, sources and mixers that can be controlled by parameters. Thanks to the frei0r collection more than a 100 effects can be shared by any application, avoiding duplicate efforts.
LiVES is a video editing system, which provides realtime editing and mixing, can apply realtime rendering effects, or just perform format conversions. It's suitable both for newcomers and VJs, available cross-platform, runs even on low-end hardware, and is extensible per RFX plugins.
Crosti helps in creating custom cross-stitching schemes from image files / photographs. It supports all common raster and vector images, permits various colorizations and adaptions, resizing and rotating templates, adding lines or circles, and obviously printing them out.
MKVToolNix is a tool collection for manipulating Matroska video (MKV) files. It can mux/demuc, split/merge, edit, inspect or create them, or convert from AVI, MP4, OGM, Dirac, h264 fromats. It supports common encodings and subtitle formats, runs on Linux, Windows and Max OS X.
EasyABC is an open source ABC editor for Windows, OSX and Linux. It uses abcm2ps and abcMIDI for typesetting the score and playing the music.
FF Multi Converter is a GUI frontend for multimedia and document conversion tools. It utilizes FFmpeg for audio and video format recoding, ImageMagick for graphic files, and UnoConv for all office document formats. It's implemented in Python with Qt4.
tkffmpeg is a simple GUI for controlling ffmpeg/avconv media file conversions. It's implemented as simple Tcl/Tk script. Generic audio and video encoding parameters can be set, such as DVD conversion options, and a progressbar is displayed.
Galapagos provides static PHP 5.4 code transformation onto 5.3 compatibility syntax constructs. It's easily run on a whole vendor/ codebase, and obviously meant for backwards compatibility depending on environment constraints.
Oggify is a command-line tool to convert between different audio formats. It's foremost intended to manage OGG Vorbis based collections, but also supports FLAC, or MP3 for older players, ALAC and MP4 on Mac OS X.
phptags automates the normalization of PHP script enclosure tokens. It can alternate between <?php long and <? short tags, add missing close tags, or dislodge them, and clean up whitespace and Unicode markers surrounding them.
Alien is a Linux software package conversion tool. It transforms between Debian (.deb), Red Had (.rpm), Solaris (.pkg) and Slackware (.tgz/txz) archives. After transforming meta data and contained installation scripts, it can even install them right away. It runs most robustly on Debian-based systems, but also works with less frequently used RPM distros.
Hasciicam makes it possible to have live ASCII video on the Web. It captures video from a TV card and renders it into ASCII, formatting the output into an HTML page with a refresh tag or in a live ASCII window or in a simple text file as well, giving anyone that has a bttv card, a Linux box, and a cheap modem line the ability to show a live asciivideo feed that can be browsable without any need for a plugin, Java, etc.
HtmlToText is a small PHP utility class to convert HTML into plain text, but preserving links in MarkDown format.