GSoC Ideas 2008

GSoC Ideas
This page represents the pick of our current project ideas.

Subheadings for each idea:

Label Track Enhancements (done 2008)
Possible Mentors:
 * James Crook, Federico Grau

Description: Audacity has flexible Label tracks for annotating sections of the audio. The method for positioning and dragging the labels allows the same kind of labels to easily be used to label points, ranges, and also maintain boundaries between regions by dragging two end points at the same time.

We're looking for proposals for the next stage of enhancements, that integrate them more into the audio editing process. Possibilities to consider include:


 * More operations on labels, such as 'apply effect at labels'.
 * Visual enhancements, such as different icons and colours associated with different kinds of labels.
 * Handling of very large numbers of labels. This requires both optimisations and new visual options.
 * Snapping of labels, so that they position at specified time intervals.
 * New ways to automatically compute labels.

A detailed proposal should make clear the Use Cases for the enhanced labels that are motivating the changes.

Skills:
 * wxWidgets and C++

Difficulty:
 * Easy. Improvements can be made in small steps.

Notes:


 * There is a discussion of labelling implementation and the features it might contain at Label Track.

Early spinoff from this work:
 * Label tracks to stick to the track above, so that they edit together.

Playback Enhancements
Possible Mentors:
 * Dominic Mazzoni, Vaughan Johnson

Description: Audacity lags behind commercial audio software in a number of details of its playback behaviour. Specific enhancements we would like a summer student to provide are:


 * No 'click' on start/stop/loop; At the moment there usually is an audible click when Audacity starts or stops playing a sound, or in iterations of playing a loop. A very short fade-in and fade-out applied only to playback should fix this.
 * Loop play adjusts dynamically to boundaries being moved; Finding the precise boundaries of a sound, for example an unwanted sound to be fixed, can be difficult with Audacity as it currently is.  The location of the sound isn't obvious from the waveform.  The new option would allow playing the sound in a loop, adjusting the boundaries to find out exactly where it starts and stops.
 * Vari-speed playback; Fast playback of sound allows sections of audio to be located more rapidly. Slow playback allows precise location (on timeline) of sound to be determined more accurately.  There is a crude version of this on the 'Transcription Toolbar' - refining it would include allowing the speed to vary during playback without starting and stopping.
 * Drag-playback-cursor whilst playing; This requires changes to both playback and GUI. It is an extension of vari-speed playback and would make locating sound more rapid.
 * Play all 'labels' on the selected label tracks; Labels can be placed on the audio both manually and automatically. This has many uses, one being the possibility of previewing a recording whilst skipping over periods of silence.

Skills:
 * wxWidgets and C++

Difficulty:
 * Moderate. Easy to vary the difficulty in either direction through choice of what to implement.

Early spinoffs from this work:
 * The schedule should plan to have some features complete to the 'release candidate' phase by the half way point. This is more useful than progressing all of the features in tandem, and perhaps completing none of them if time runs out.

Bridges
Possible Mentors:
 * Federico Grau (for Rivendell); Bartek Golenzo (Octave).

Description: One way to grow the feature set of Audacity and at the same time to avoid re-inventing the wheel is to build compatibility 'bridges' between Audacity and other Open Source programs. This is an example of making Connected Open Source a reality. Two examples of bridges for Audacity are:
 * Bridge to Octave - Octave is an Open Source program for mathematical analysis and is useful in digital signal processing (DSP). Audacity could have a bridge to Octave that allows Octave to apply effects to Audacity waveforms and to annotate Audacity waveforms with labels.
 * Bridge to Rivendell - Rivendell is an Open Source program for radio station management. The Rivendell bridges already allows Audacity and Rivendell to exchange playlists.  Work on it would improve the integration.

A proposal for a new bridge should go into some detail as to what features of the other program will be bridged. Generally the plan should avoid extensive work on the other program, since the point of the project is to extend Audacity.

This is part of the Connected Open Source initiative, aiming to build more bridges between Open Source projects.

Skills:
 * wxWidgets and C++
 * Familiarity with Octave or Rivendell or other software being bridged to.

Difficulty:
 * Moderate to Hard. Student has to get familiar with two programs.

Notes:
 * The Octave bridge is probably too difficult to do without a mentor who is very familiar with Octave, and so now unlikely to go ahead unless we find a mentor for it in the time.
 * As we already have active development on the Rivendell bridge, and a mentor committed to it, the focus on the Rivendell bridge will be making it more flexible and a cleaner separation. Talk with Federico for details.  Done well this will be a model for other future bridges.

Early spinoff from this work:
 * A restricted bridge which exposes a smaller part of the functionality.

FFmpeg integration (done 2008)
Possible Mentors:
 * Richard Ash, Dominic Mazzoni, Vaughan Johnson, Federico Grau

Description: A patch has been produced in the past to use FFmpeg libraries for importing and exporting audio files in a wide variety of audio formats. This however was against 1.2.x and will require considerable changes to integrate it with current Audacity code. There will also be issues surrounding the build system and ensuring license requirements are met when distributing the resulting program.
 * Import needs to decode the imported files into Audacity, handling varying channel counts sensibly.
 * Metadata in imported files should be fed into the Audacity meta-data handling so it can be stored, edited and used for exported files.
 * A decision is needed on what to do if video files (with and without sound tracks) are presented.
 * Export will need to work out how to provide a user interface to handle choice of codec and container formats.
 * Export should cater for multi-channel output where applicable with more than 2 output channels, using the export routing code already in place.
 * Export needs to write relevant metadata to the exported file from the available Audacity metadata and user interface.

Skills:
 * wxWidgets and C++
 * Must be prepared to work on both Windows and Linux and ideally Mac OS X too.

Difficulty:
 * Moderate. (Assuming nothing is done with video and the interface is kept simple).

Notes:
 * This is proving far and away the most popular option at the moment. Unlike audio-diff we can't run more than one of these.  There is a second 'integrating a library' project, the Nyquist one (below).  So far no one has applied for it.  Students may want to consider making at least a place-holder application for the Nyquist project too.  Then they have the option of beefing it up later through adding / modifying the comments.
 * For students interested in working on the Codecs rather than on directly progressing Audacity, FFMPEG have projects proposals, and so do Xiph for Speex and Ogg.

Early spinoffs from this work:
 * Importer is probably easier to do and independent of export. Adding an importer should not be terribly hard to do, at least for mono and stereo files which covers most use cases. No interface modifications needed to do this, and enabling / disabling it at build time is clean and follows other importers.
 * Metadata support can be implemented after other parts are complete / working.

Nyquist (Lisp) update
Possible Mentors:
 * Roger Dannenberg

Description: Upgrade Nyquist support in Audacity to the latest version.

Nyquist is a version of the Lisp language built into Audacity.

Skills:
 * C++.
 * Developing on Linux and Windows.

Difficulty:
 * Moderate.

Notes:
 * We will also consider other proposals for Lisp work using Nyquist, especially if they will help popularise Lisp and the Nyquist extensions in Audacity. If you choose that route, please contact the  before putting significant work into your proposal.

Early spinoff from this work:
 * Demonstrate the upgrade on one of the two platforms.
 * If there are no unanticipated hitches, the project will be easily achievable in the 8 weeks. A good project proposal based on this idea should include other improvements for the Audacity Nyquist user too.  For inspiration look at the archives of the audacity-nyquist list at Sourceforge.  These would happen in the second half of the project after the basic upgrade.

Intuitive cross-fading
Possible Mentors:
 * Vaughan Johnson, Dominic Mazzoni, Federico Grau

Description: One of the most common operations people want to do when mixing audio is to smoothly transition between two sound clips. This is commonly called a cross-fade. This operation is technically possible in Audacity now, but it is very clunky, requiring multiple steps and no editability short of undoing the actions and starting again. We are looking for someone to implement a clean, intuitive, nondestructive cross-fade for Audacity. Audacity already has all of the infrastructure necessary to support implementing this operation nondestructively and we already have a clear plan for how it should work. The following web page has a mock-up of what we think the GUI might look like:

This feature, while seemingly small, would represent a huge boost in usability for Audacity. This feature is intimately related to several other UI enhancements that we have proposed: for example, one element of this proposed GUI is that clips "stick" to each other or "snap" into place when you push them together. Such a snap-to behavior would be great in several other circumstances, for example having a track stick to t=0, or to a point that lines up with another track.

Skills:
 * wxWidgets and C++

Difficulty:
 * Moderate.

Early spinoffs from this work:
 * Ability for all effects to be faded in/out automatically. This can avoid clicks in some circumstances.

Bugfix Ninja
Possible Mentors:
 * Richard Ash, Dominic Mazzoni, Vaughan Johnson, Leland Lucius, Federico Grau, James Crook

Description: We have several pesky bugs that have been preventing us getting a new stable release out, and many more details of lesser importance that make the program less good than it might be. We could very much use help vanquishing these. Have a look at the priorities on our Release Checklist and our list of "aim to's" which we currently aren't able to progress.

This project would have a GSoC student working just on clearing issues, helping us to produce a high quality release. This is how established Open Source developers work when they are not adding major new features. You'll learn a great deal about working on Open Source, and particularly the way people collaborate to solve problems. This is a very different project idea to most of the others.

The difficulties for this proposal for GSoC are:


 * The 'plan' showing what you intend to do - particularly so we can assess whether you have done it and you can get paid. Sometimes an apparently small issue actually opens up a big can of worms.  The plan needs to have flexibility in it.  One way to do that is with a 'points system' for the issues, where you say something like 'I plan to have 60 points worth of issues tackled by the half way stage, and 100 points worth by completion'.  This allows you to move on from an issue if it turns out to be way harder than was thought.


 * The second difficulty is convincing us that you can work in this way. You'll need to convince us that you've understood some of the issues on our lists and that you can tackle them.  Show you've understood both the issue and the code involved.

The reward is that you would help Audacity tremendously, and be a hero to us!

Skills:
 * wxWidgets and C++
 * A knack for asking the right questions.
 * Comfortable with visiting many different pieces of code in a large project.

Difficulty:
 * Moderate to Hard.

Early spinoffs from this work:
 * At least one of the meatier 'P1 or P2 issues' solved.
 * At least five smaller 'P3 to P5 issues' finally closed.

More ideas
There are further ideas on our More GSoC Ideas page. Also see our Use Cases and Feature Requests pages (over 200 requests), which may suggest ideas for a project proposal.