In a 1999 study funded by Microsoft, National Software Testing Laboratories (NSTL) found that listeners preferred WMA at 64 kbit/s to MP3 at 128 kbit/s (as encoded by MusicMatch Jukebox). Both MP3 and WMA encoders have undergone active development and improvement for many years, so their relative quality may change over time. Players Apart from Windows Media Player, most of the WMA compression formats can be played using ALLPlayer, VLC media player, Media Player Classic, MPlayer, RealPlayer, Winamp, Zune Software (with certain limitations—DSP plugin support and DirectSound output is disabled using the default WMA plugin), and many other software media players. The Microsoft Zune media management software supports most WMA codecs, but uses a variation of Windows Media DRM which is used by PlaysForSure. The FFmpeg project has reverse-engineered and re-implemented the WMA codecs to allow their use on POSIX-compliant operating systems such as Linux. The Rockbox project further extended this codec to be suitable for embedded cores, allowing playback on portable MP3 players and cell phones running open source software. RealNetworks has announced plans to support playback of DRM-free WMA files in RealPlayer for Linux. On the Macintosh platform, Microsoft released a PowerPC version of Windows Media Player for Mac OS X in 2003, but further development of the software has ceased. Microsoft currently endorses the third-party Flip4Mac WMA, a QuickTime component that allows Macintosh users to play WMA files in any player that uses the QuickTime framework. Flip4Mac, however, does not currently support the Windows Media Audio Voice codec. Not all Android devices have native support for WMA files because the core Android platform doesn't support this format, but third-party software that supports it also exists. WMA format can be played in almost all Windows Mobile and later Windows Phone devices. Encoders Software that can export audio in WMA format include Windows Media Player, Windows Movie Maker, Microsoft Expression Encoder, Sony Sound Forge, GOM Player, RealPlayer, Adobe Premiere Pro, Adobe Audition, and Adobe Soundbooth. Microsoft Office OneNote supports encoding in all WMA codecs, and Windows Media Encoder supports all available bit rate and resolution options as well. Open source players like VLC media player can also do some encoding. Digital rights management The WMA codecs are most often used with the ASF container format, which has an optional DRM facility. Windows Media DRM, which can be used in conjunction with WMA, supports time-limited music subscription services such as