Audacity: A Free, Cross-Platform Digital Audio Editor Version 1.3.0 (beta) For changelog, see the bottom of this document. WWW: http://audacity.sourceforge.net/ Email: audacity-help@lists.sourceforge.net Lead Developers: Dominic Mazzoni (project leader) Matt Brubeck James Crook Vaughan Johnson Markus Meyer Developers: Joshua Haberman Monty Montgomery Shane Mueller Contributors: Lynn Allan (CleanSpeech) William Bland (Time Tracks) Roger Dannenberg Brian Gunlogson Greg Mekkes Abe Milde Paul Nasca Tony Oetzmann Augustus Saunders Martyn Shaw Mike Underwood Tom Woodhams Wing Yu The Audacity Logo: Harvey Lubin http://www.agrapha.com/ Audacity is based on code from the following projects:: expat FLAC LAME libmad libsndfile Nyquist Ogg Vorbis PortAudio Resample SoundTouch wxWidgets Special Thanks: Richard Ash Dave Beydler Jason Cohen Dave Fancella Steve Harris Daniel James Daniil Kolpakov Robert Leidle Logan Lewis David Luff Jason Pepas Mark Phillips Jonathan Ryshpan Patrick Shirkey David R. Sky Tuomas Suutari Mark Tomlinson David Topper Rudy Trubitt StreetIQ.com Verilogix, Inc. ------------------------------------------------------------- This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program (in a file called LICENSE.txt); if not, go to http://www.gnu.org/copyleft/gpl.html or write to Free Software Foundation, Inc. 59 Temple Place - Suite 330 Boston, MA 02111-1307 USA ------------------------------------------------------------- Source code to this program is always available; for more information visit our website at: http://audacity.sourceforge.net/ Audacity is built upon other free libraries; some of these libraries may have come with Audacity in the lib-src directory. Others you are expected to install first if you want Audacity to have certain capabilities. Most of these libraries are not distributed under the terms of the GPL, but rather some other free, GPL-compatible license. Specifically: wxWidgets: LGPL Cross-platform GUI library - must be downloaded and compiled separately. expat: BSD-like license. Provides XML parsing. Included with Audacity iAVC: LGPL Part of the code to the AVC Compressor effect. Included with Audacity. libid3tag: GPL Reads/writes ID3 tags in MP3 files. Optional separate download as part of libmad. libmad: GPL Decodes MP3 files. Optional separate download. libnyquist: BSD-like license. Functional language for manipulating audio; available within Audacity for effects processing. libogg: BSD-like license. Optional separate download, along with libvorbis. libsndfile: LGPL Reads and writes uncompressed PCM audio files. Included with Audacity. libvorbis: BSD-like license. Decodes and encodes Ogg Vorbis files. Optional separate download. For more information, see the documentation inside each library's source code directory. ------------------------------------------------------------------------- Additional copyright information: ------------------------------------------------------------------------- Nyquist Copyright (c) 2000-2002, by Roger B. Dannenberg All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions of source code must retain the copyright notice, the list of conditions, and the disclaimer, all three of which appear below under "COPYRIGHT AND LICENSE INFORMATION FOR XLISP." Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Redistributions in binary form must reproduce the copyright notice, the list of conditions, and the disclaimer, all three of which appear below under "COPYRIGHT AND LICENSE INFORMATION FOR XLISP," in the documentation and/or other materials provided with the distribution. Neither the name of Roger B. Dannenberg, Carnegie Mellon University, nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission. COPYRIGHT AND LICENSE INFORMATION FOR XLISP (part of Nyquist): Copyright (c) 1984-2002, by David Michael Betz All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of David Michael Betz nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ------------------------------------------------------------- Compilation instructions: First you must download wxWidgets from: http://www.wxWidgets.org/ If you install the RPM, make sure you install the devel RPM as well, otherwise, you won't be able to compile Audacity from source. To compile on Linux, Mac OS X, and other Unix systems, simply execute these commands: ./configure make make install # as root To see compile-time options you can set, you can type "./configure --help". If you want to do any development, you might want to generate a configure cache and header dependencies: ./configure -C make dep To compile on Windows using MSVC++, please follow the instructions found in compile.txt in the "win" subdirectory. For more information on compilation (CodeWarrior for Mac is also supported) please email audacity-help@lists.sourceforge.net ------------------------------------------------------------- Known issues/problems: * Audacity can import and display MIDI files, but they cannot be played or edited. * Recording in full duplex (play existing tracks while recording) on some Linux systems causes the recording to sound slowed-down. * MacOS X only: Audacity cannot work with files or folders that are contained inside folders with international characters (accent marks, etc.) in their names. Note that files with accented characters work, and Audacity projects with accented characters work. Only files inside of folders with accented characters in their names will cause problems. * Windows only: Audacity is incompatible with some professional sound cards and may crash if one of these cards is the default when you open Audacity. As a workaround, make a different sound card your default when using Audacity, but please let us know if this affects you so that we can track down and solve the problem. Also note that the Windows installer will replace 1.0.0 installations, but not the 1.1.x beta installations. ------------------------------------------------------------- Changes in 1.3.0: Beta warning Audacity 1.3 is an unstable, beta version of Audacity. Users who want a completely stable, finished program should be using Audacity 1.2. Audacity 1.3 has hundreds of new features, but some features may be incomplete or confusing, it is more likely to crash, and you are more likely to lose data. You can install both Audacity 1.2 and 1.3 on the same machine. When this branch of Audacity is finished, it will be released as version 1.4, which will be stable and complete. Audacity 1.3.0 is currently only available in English. Future Audacity 1.3 releases will be translated into many other languages. New features The new features in Audacity 1.3 have been grouped into the following six major categories. 1. Collapse/Expand Tracks In Audacity 1.3, every track has an upward-pointing triangle at the bottom of the label area on the left side of the track. 2. Multiple clips per track In Audacity 1.2, there is one audio 'clip' per track. There is no easy way to time-shift part of a track without moving the rest. In Audacity 1.3, you can split a single track into multiple clips. You can move these clips around between different tracks, making it easy to construct complex compositions out of hundreds of smaller audio samples. 3. Selection Bar In Audacity 1.2, the current selection is contained in a status bar at the bottom of the window. In Audacity 1.3, this is replaced by a fully functional Selection Bar, which displays and controls the current selection (your choice of Start and End, or Start and Length), and the current audio position. The selection bar is fully editable - just click in any field and type to change the current selection precisely. In addition, many formatting options allow you to view times in different units, such as samples, CD frames, or NTSC video frames. 4. Improved Label Tracks Label Tracks are Audacity's way for you to create markings 3 and annotations within your project. In Audacity 1.3, Label Tracks are much improved, with support for overlapping labels, and support for modifying both the left and right edge of the label region just by clicking and dragging. 5. QuickTime and Audio Units on Mac OS X On Mac OS X, Audacity can now import and audio file supported by Apple's QuickTime technology. This includes .MOV and .MP4 (AAC) files. Unfortunately encrypted audio files (such as those from the iTunes Music Store) cannot be imported directly into Audacity - Apple does not allow this to be done easily because it would be too easy to circumvent the encryption this way. Also on Mac OS X, Audacity now supports Audio Unit plug-ins. Audacity searches for Audio Units in the usual location, in the system or user's Library folder. 6. Other features Better performance with large projects Project integrity check on open Transcription toolbar Upload Batch Cut lines CleanSpeech Changes in 1.2.4: * The File menu now includes a list of recent files. * The "Generate Silence" effect now prompts for a length. * Audacity is now built with Vorbis 1.1, which features better encoding quality and file compression. * Dragging sound files into the Audacity window now works on Mac OS X and Linux, as well as Windows. (Before, it worked only on Windows.) * The "View History" window can now discard old undo levels to save disk space on Windows. (This previously worked only on Linux and Mac.) * "Preferences" command is now in Edit menu. * "Plot Spectrum" command is now in Analyze menu. * Opening a project file saved by a later version of Audacity displays an intelligent error message. Also, trying to import a project file (instead of open it) displays an intelligent error message. * Audacity now compiles in Visual C++ .NET 2003. * Other minor bug fixes. * New or updated translations: Arabic (ar), Czech (cs), Finnish (fi), Hungarian (hu), Japanese (ja), Norwegian (nb), Slovenian (sl), Simplified Chinese (zh_CN), Traditional Chinese (zh_TW). Changes in 1.2.3: * Fixed a bug that caused recording to stop or display incorrectly after about 50 minutes on some Windows systems. (This was partly fixed in Audacity 1.2.2, but still didn't work on some systems.) * The Change Pitch and Change Tempo effects have been upgraded to use a new version of the SoundTouch library by Olli Parviainen, with better speed and higher quality. * libsndfile has been upgraded to version 1.0.11. * Fixed a bug that caused the program to run slowly when using the Envelope tool. * Shift-clicking on a mute or solo button now un-mutes (or un-solos) all other tracks. * Nyquist plug-ins can now accept strings as input. Also, a "Debug" button has been added to Nyquist effect dialogs, which allows you to see all of the output produced by Nyquist, for aid in debugging. * When the audio file referenced ("aliased") by an Audacity project is missing, Audacity will now always play silence. Before, Audacity would sometimes repeat the most recent audio that was played previously. * VU Meters will now always reset when audio I/O has stopped. * Fixed a major Mac-only bug that was causing Audacity to crash at seemingly random times, but especially during audio playback and recording. * New or updated translations: Italian (it), Hungarian (hu), Ukrainian (uk), Spanish (es). Polish (pl), Simplified Chinese (zh), Norsk-Bokmal (nb), French (fr). Changes in 1.2.2: * VU Meters added for both playback and recording. Click on the recording meter to monitor the input without recording. * Export Multiple - new feature that lets you export multiple files at once, either by track, or split based on labels. * Attempt to automatically correct latency in full-duplex recordings. (This does not work perfectly, and is not yet supported on all systems. It will improve in future versions.) * Fixed a serious bug that could cause data loss when you save and then reload and re-edit an Audacity project containing repeated or duplicate data. * MP3 tags dialog will only pop up the first time you export as MP3; after that it will not pop up again as long as you have filled in at least one tag. * You can now add a label at the current playback position - in the Project menu, with a shortcut of Ctrl+M. * Clicking on a label now selects all of the tracks, making it easier to use the label track to recall selections. * Windows: Fixed a crash in the Time Track "Set Rate" command. * Fixed a bug that caused problems with recordings over 45 minutes on some Windows systems. * Mac OS X: Improved support for the Griffin iMic by fixing a bug that was causing it to always record in mono instead of stereo. * Added support for Software Playthrough (listen to what you're recording while recording it, or while monitoring using a VU meter) - this makes it possible, for example, to record using one audio device while listening to it play through a separate device. * Unix/Linux: Fixed freeze caused by captured mouse when audio device hangs. (Audacity may not respond, but it will no longer freeze all of X.) * Fixed a cosmetic bug that caused improper waveform display if you tried to open an Audacity project saved on a different platform (e.g., copying a project from a Mac to a PC). * Fixed bug that could cause instability when pasting, splitting, or duplicating a label track. * You can now change the font of a label track by choosing "Font..." from the label track's pop-up menu. * Basic printing support has been added. Currently it scales the entire project to fit exactly on one page. Try printing in landscape orientation for best results. * Mac OS X and Windows: Audacity ships with a newer version (1.0.1) of the Ogg Vorbis encoder. Vorbis compression will now have higher quality and smaller file sizes. * Fix a bug that occasionally caused crashes when applying effects to split tracks. * Zoom In / Zoom Out now properly disable when they're not available. * Fixed disk memory leak in Preview * Other minor bug fixes and performance improvements. Changes in 1.2.1: * The following translations have been added or updated: Finnish, French, Hungarian, Italian, Japanese, Norwegian, Polish, Russian. * Fix a bug that could cause data to be lost when pasting audio from one project into another, after the first project has been saved and closed. * Fix a possible crash when opening or resizing the Equalization window, especially when using large system fonts. * Don't allow percentages less than -100% in Change Pitch/Speed/Tempo effects (fixes a possible crash). * Fix a crash when the temporary directory is not available on startup. * Correctly load ID3 tags saved in Audacity project files. * On Linux and OS X, store lockfiles in the temp directory instead of the user's home directory. This fixes problems in lab environments where users have restricted or network-mounted home directories. * Fix a bug that prevented Nyquist effects from running when certain regional settings were activated. * Fix a bug in the Quick Mix command that could cause old temporary files to not be deleted. * Linux: Fix endianness problems in playback on PowerPC. * Linux: Fix compilation problem in Nyquist on MIPS. * Linux: Include a more recent PortAudio v19 snapshot (fixes compilation problems when building with the --with-portaudio=v19 option). * Two new Nyquist plug-ins: "Cross Fade In" and "Cross Fade Out." * Other minor bug-fixes. Changes in 1.2.0: * New cross-fade effects. * Fix problem where samples were drawn in the wrong position when zoomed all the way in. This caused the drawing tool to move a different sample than the one under the cursor. * Don't use id3v2.4 tags, which are not yet supported by most players. (This was fixed in 1.2.0-pre2, but appeared again by accident in 1.2.0-pre3.) * Correctly display translated messages in the status bar. * When the cursor is on-screen, the Zoom In button now zooms to the area around the cursor. * Mac OS X: Fixed audio problems on the Apple PowerMac G5. * Linux/ALSA: Work around a bug in ALSA's OSS emulation that caused Audacity's playback cursor to move too quickly. * Microsoft Windows: The Audacity source code should now compile out of the box on Windows. * Many new/updated translations. Changes in 1.2.0-pre4: * Fixed problems that could occur when importing certain non-seekable PCM audio files, such as GSM610. * Fixed bug that was causing the samples to shift off-screen horizonally when zoomed in very far and the track had a time-shift offset. * Fixed bugs in the new resampler that added noise to resampled audio on some systems. If you experienced noise when exporting to a WAV, MP3 or OGG file you may have been bitten by this bug. * Fixed bug that led to occasional crashes when using the time-shift tool in conjunction with high zoom factors. * Dithering is now only applied on export when it is really necessary (e.g. when converting float samples to 16-bit). * Files that only contain mono tracks are now automatically exported to stereo files when they contain tracks which are panned to the left or the right. * The Delete key can now be used to delete the current selection, in addition to the Backspace key. * Fixed bug where Audacity didn't ask whether to save changes if you close the project or exit while recording. * Mac OS X: Supports Playthrough (listen to what you're recording while recording it) if your hardware device supports it. * Mac OS X: Audacity is now a package (you can right-click on Audacity.app and select 'Show Package Contents'). Launch time has improved significantly. * MS Windows: Fixed problem that caused Windows XP to use the short name of a file ("TESTFI~1.AUP"), which led to problems when the file was later opened again using the long file name. * MS Windows: Fixed bug that caused file exports to fail if the destination directory was the root folder of a Windows drive. * MS Windows: Audacity's application information which is written to the Windows registry now always contains the full path to the executable. * MS Windows: Fixed problems in trying to set the Windows registry as non-admin user, for file-type associations. * Make sure the "Save" command is enabled after changing gain and pan sliders. * Updated translations. Added translator credits to the "About" window in localized versions. Changes in 1.2.0-pre3: * Fixed bug where Export is grayed out when nothing is selected. * Fixed crash caused by opening Audacity on a computer with a high-end sound card with no mixer support. * Fixed crash in Import Raw. * Fixed New Stereo Track. * Cosmetic fixes for Mac OS X. * Support for the VST Enabler on Windows added. * Fixed crash if you close Audacity while the Preferences dialog is open. * Fixed duplicate-character bug in Mac OS X Label Tracks. * The recording level control on Linux now adjusts the IGAIN, rather than the playthrough level of the recording source. * Fixed bug that caused corruption to 16-bit stereo recordings. * Fixed bug that caused data loss if you deleted all tracks in a saved project and then open a new file into the same window. * Added support for alternate audio button order (in Interface preferences) * Added preliminary support for wxX11 * Added fully transparent Windows XP icon * Fixed crash if you try to record (or play) and no audio devices exist, or if the audio device doesn't support the mode you selected. * Audacity no longer sets the process priority to high while recording on Windows. Users can still do this manually using the Task Manager. * Fixed bug that caused last ~100 ms of the selection to get cut off on Windows. * Fixed FFT Filter and Equalization effects dialogs. * Fixed bugs in Unix build system (DESTDIR in locale directory, choosing libsamplerate instead of libresample) * Support for LADSPA plug-ins on Windows added, and three open source LADSPA plug-ins ported to Windows (GVerb reverb, SC4 compressor, and Hard Limiter) Changes in 1.2.0-pre2: * Online help completed. The full manual is nearly complete and will be posted to the website for online browsing shortly. * Audacity will no longer let you do unsafe editing operations while playing or recording. This eliminates many potential crashes. * Fixed ability to cancel Quit button. * New resampling library, with no restrictions on the maximum or minimum rate of resampling. * Audacity now supports LADSPA plug-ins on all platforms, and supports VST plug-ins through an optional LADSPA plug-in called the "VST Enabler", which you can download separately. Because of licensing issues, Audacity cannot be distributed with VST support built-in. * Mac OS X keyboard shortcut problems have been fixed. * Mac OS X audio muting problems have been fixed. * Mac OS X playback/recording cursor sync problems have been fixed. * Silence now displays a straight line again, instead of nothing. * Added a vertical ruler to the Waveform dB display. * Fixed crash in Change Pitch. * You can now Paste if nothing is selected. * Canceling an Import operation doesn't cause an extra error dialog to appear. * Audacity now handles filenames with international characters correctly. * Now outputs ID3v2.3 tags (instead of ID3v2.4), to be compatible with more MP3 players. * Minor improvements to build system on Unix systems. New features in Audacity 1.2: * User Interface - Vertical zooming of tracks. - Improved look and placement of toolbars. - New custom mouse cursors. - Complete implementation of editable keyboard shortcuts. - Find zero-crossings. - Mouse wheel can be used to zoom in and out. - Multi-Tool mode. - Amplify using envelope. - Labels can store selections (like Audacity 1.0.0). * Effects - Repeat Last Effect command - Improved VST plug-in support - Most effects now have a Preview button - Compressor (Dynamic Range Compressor) - Change Pitch (without changing tempo) - Change Tempo (without changing pitch) - Change Speed (changing both pitch and tempo) - Repeat (useful for creating loops) - Normalize (adjust volume and DC bias) * Audio I/O - 1-second preview command. - Looped play. * File I/O - Audacity 1.2.0 opens project files from all previous versions of Audacity from 0.98 through 1.1.3. - Open multiple files from the same dialog. - Use a text file to specify a list of audio files to open with offsets. * Updated user manual * Bug fixes - Project files with special characters are no longer invalid. - "Scratchy" noises caused by bad clipping are fixed. - Audacity no longer exports invalid Ogg files, and does not cut off the last few seconds of exported Ogg files. - Mono MP3 files now export at the correct speed. - Many incorrect results from the Envelope tool have been fixed. - The "Export Labels" command now overwrites existing files correctly. - The "Plot Spectrum" window displays the correct octave numbers for notes. - Several memory leaks are fixed. New features in Audacity 1.1.3: * User Interface - New Mixer toolbar allows you to control the output volume, input volume, and input source directly from Audacity. - Every track now has its own gain and pan controls. * File I/O - Uses improved project file format. (Unfortunately reading previous formats, including 1.1.1, is not supported.) - Block files (stored in Audacity project directories) now use the standard AU format. Though some Audacity meta-information is in these files, they can now be read by many other popular audio programs as well. - Fixed some bugs relating to reading/writing audio files with more than 16 bits per sample. - Import RAW is functional again, with a simpler GUI but support for far more file formats. The autodetection algorithms are much more accurate than in 1.0. * Audio I/O - Completely rewritten audio I/O, with lower latency and minimal chance of buffer underruns while recording. * Resampling - Using high quality resampling algorithms, with the option of better quality for mixing than for real-time playback - Preliminary support for Time Tracks, for changing playback speed over time. * Many more bug fixes and new features New features in Audacity 1.1.2: * User Interface - Fixed bug in Windows version, for track menu commands "Name..." and "Split Stereo Track"/"Make Stereo Track". * Effects - Nyquist support on Windows (supports plug-ins written in Nyquist, an interpreted functional language based on Lisp). New features in Audacity 1.1.1: * User Interface - Tooltips appear in Statusbar. - Vertical cursor follows play/record - Pause button - Drawing tool (with three different modes) - Vertical Resizing of stereo tracks is more fun. - Adjust selection by click-dragging selection boundary - Toolbar button context-sensitive enabling/disabling - Better zooming functionality (centers region) - Multiple ways to display the cursor position and selection - Snap-to selection mode - Drag tracks up and down - Align and group align functions - Cursor save/restore - Working history window * Effects - Effects broken down into three menus: Generate, Effect, and Analyze - Generate menu lets you generate silence, noise, or a tone - Nyquist support (supports plug-ins written in Nyquist, an interpreted functional language based on Lisp) * Localization - Improved localization support - More languages available - Language selection dialog on startup * Mac OS X - Support for more audio hardware - Support for full-duplex (play while recording) - Support for MP3 exporting using LameLib Carbon * Unix - Audacity now has a man page (it describes command-line options and how to set the search path) * File Formats - Uses libsndfile 1.0, which fixes some bugs and improves performance * Searching for Files: - On Windows and Mac OS, Audacity now looks for translations in the "Languages" folder and all plug-ins in the "Plug-ins" folder, relative to the program. - On Unix, Audacity looks for translations in /share/locale and looks for everything else in /share/audacity and also in any paths in the AUDACITY_PATH environment variable New features in Audacity 1.1.0: * Core audio processing: - Support for 24-bit and 32-bit sample formats - Automatic real-time resampling (using linear interpolation) * Effects: - Support LADSPA plugins on Linux / Unix * File formats: - New XML-based Audacity project format - Full Ogg Vorbis support now (importing and exporting) - Export to any command-line programs on Unix - Support for reading and writing many more types of uncompressed audio files, including ADPCM WAV files. * Toolbars - New toolbar drawing code; automatically adopts your operating system's colors - New toolbar buttons (Skip to Start, Skip to End) - New Edit toolbar - Toolbar buttons disable when they're not available * User Interface - Fully customizable keyboard commands - Autoscroll while playing or recording - New Ruler, used in main view and in FFT Filter effect - The waveform now displays the average value in a lighter color inside the peak values * Localization - Audacity can now be localized to different foreign languages. New libraries in Audacity 1.1: * libmad for fast MP3 importing * libid3tag for editing MP3 file information * libsndfile to read and write more audio file formats * PortAudio for cross-platform audio playing and recording