When will Audacity support AC3 ?

pstein · January 4, 2008, 11:04am

Without that AC3 feature Audacity is not very useful for me and for all other users who deal with AVIs
and video material.

Is this a technical or license problem?

steve · January 8, 2008, 7:48pm

It’s probably a licensing issue since AC-3 is a proprietary format of Dolby Digital.

For editing purposes it’s much better to use a lossless format, such as wav or aiff than using a lossy compression such as AC-3, which is why both audio and video editing programs use uncompressed audio during editing.

Some editors will support importing/exporting of AC-3, simply by decoding it on import and re-compressing it on export, but internally they will be using an uncompressed format, just the same as Audacity.

If you need to convert to or from AC-3, you can use a standalone format converter such as SUPER.

pstein · January 9, 2008, 8:16am

“Reading” should never be a problem. RAR archiving format license for example is also protected by RarLabs
but DE-compressing is always allowed. You need only a license for using the compressig algorithm.

Same with AC3.

For AC3 I need only de-compressing. Similarly to GoldWave I just want to drag & drop
an AVI onto Audacity and it should decompress it internally to another format XXX.
At the end (after cut/paste/volume change) I want to have the option to save it as WAV, LameMP3, or another format.

This should all be possible without license…

audacity · January 9, 2008, 2:50pm

good point, the same would apply to WMA.

steve · January 9, 2008, 8:19pm

It’s not necessarily that simple. Since Audacity is open source, all the code that is in it must be freely available for redistribution both as source code and in the compiled form. Although specific utilities may be available for free use, they may be subject to license restriction that prevent them from being distributed in these forms. One example of this is ASIO support. Audacity can legally support ASIO, but can not be distributed with ASIO support, therefore ASIO is only available for individuals who are prepared to compile Audacity from source code with the optional Steinberg ASIO SDK . This support is provided strictly on the basis that it is NON-DISTRIBUTABLE i.e. you may NOT copy or distribute builds including ASIO support to any third parties. http://audacityteam.org/wiki/index.php?title=ASIO_Audio_Interface

The Audacity development team must decide whether to include proprietary technologies and restrict the license, or to keep the program fully open source. The decision so far has been to keep Audacity fully open source under GPL.
http://audacityteam.org/about/license

Goldwave is closed source, non-free software.

pstein · January 11, 2008, 9:01am

Why not putting the license protected parts in a pre-compiled DLL and keep only the remaining “Main” source open source ?

steve · January 11, 2008, 4:08pm

In the case of ASIO - because Audacity would be sued by Steinberg.

audacity · January 15, 2008, 7:52am

The freeware JetAudio(http://www.jetaudio.com) supports ogg, FLAC, WMA7 & WMA9.

The commercial version supports MP3 and mp3PRO.

Here under the licences agreement quotes on version 7.0.2.3010 Basic (freeware):
MPEG Layer-3 audio compression technology licensed by
Fraunhofer IIS and THOMPSON multimedia.
(http://www.iis.fhg.de/amm)

Microsoft, Windows Media, and the Windows Logo are
trademarks or registered trademarks of Microsoft Corporation
in the United States and/or other countries.

FLAC audio file format
Copyright (C) by Josh Coalson

RealSystem(r) technology is provided under license from RealNetworks, Inc., copyright (c) 1995-2001 RealNetworks, Inc. and/or its suppliers. 2601 Elliott Avenue, Suite 1000, Seattle, Washington 98121, U.S.A. Patents Pending. All rights reserved.
RealNetworks and RealSystem are registered trademarks of RealNetworks, Inc.

audacity · January 16, 2008, 5:55pm

My previous post was to illustrate that there migth be a way for audacity to import corporate formats (like AAC, WMA, etc.) and export to a free one.

today, I discover a wonderful freeware “Super” (http://www.erightsoft.com) :

SUPER © IS UNIVERSAL as it supports a wide variety of input/source file format to play
or encode (to & from) without any additional third party software.
Supported input source file formats are:

Video format: 3gp/3g2(Nokia,Siemens,Sony,Ericsson) asf, avi (DivX,H263,H263+,H264,XviD,MPEG4,MSmpeg4 etc…), dat,
fli, flc, flv (used in Flash), mkv, mpg (Mpeg I,Mpeg II), mov(H263,H263+,H264,MPEG4 etc…), mp4(H263,H263+,H264,MPEG4), ogg,
qt, rm, ram, rmvb, str (Play Station), swf (Flash), ts (HDTV), viv, vob, wmv
Audio format: aac, ac3, amr, mmf, mp2, mp3, mp4, mpc, ogg, ra, wav, wma
AviSynth Script Files: avs. Let you specify advanced encoding commands using AviSynth scripts!
SUPER © supports the conversion (encoding both ways, to & from ) of ALL the listed formats.