Features We Can't Implement
There are a number of features that users regularly request for Audacity, but which we are prevented from adding because of the restrictions placed on us by (Commercial) third parties. Unless they change their licensing conditions, we cannot add these features to audacity.
- VST GUI support. We cannot implement this because the VST interface is owned by Steinberg (now part of Yamaha). The license for the tools needed to support VST GUIs forbbids anyone from distributing the source code used to display the interface. Audacity's license (the GPL) requires that the full source code is made available to everyone, so we cannot use anything which we are not permitted to distribute to others.
- ASIO Support This is subject to the same restrictions as the VST interface above. We could create an ASIO version of Audacity quite easily, but if we distributed it with its source code, we would be breaking the Steinberg license agreement, and if we distributed it without the source code we would be breaking the licenses for Audacity and all the other libraries it relies on. Note that Audacity 1.3.3 can be compiled from source code on Windows with the ASIO SDK to give ASIO support, but this is on the strict understanding that this ASIO enabled build must not be distributed in any way. Our inability to distribute pre-compiled versions of Audacity with ASIO support will remain until Steinberg relaxes licensing. See here for more information.
- Import/Export WMA files on Windows (Why only on Windows? On other platforms, you could have the option of using different (e.g. mplayer) libraries.) The WMA format is protected by Microsoft patents, which means that regardless of the libraries used, there are restrictions on what you can do with the format. That's the whole point of software patents, and for WMV (video) files, they have already been enforced against another Open Source project, Mplayer seems to get away with distributing the Win32 DLLs and using them in a way Microsoft never intended, but their only download sites are in Eastern Europe, where the patents (probably) don't hold.
- is a proprietary technology owned by Propellerheads Software AB that permits real-time streaming of audio data between applications, typically between Propellerheads' Reason sequencing software and a mixer application such as Cubase. As in the above cases, the Rewire licensing agreement requires non-disclosure of their software code, which is contrary to the open-source licence that Audacity is distributed under. As a result Audacity cannot implement Rewire support.