Winamp Highlights:
* New portable device features - transcoding, new sync options, USB thumbdrive player support, video sync, direct-from-device playback
* Faster ripping
* Improved AAC and aacPlus encoding
* Unicode metadata, filename, and title support
* iTunes-compatible gapless playback (MP3/M4A) and encoding (M4A)
* Optional 24bit playback
* ReplayGain support

Winamp Player Features:
- Plays Music and Video Files (aacPlus, MP3, AAC, WMA and more!)
- Compatible with Winamp 2 Plug-ins
- Full Support for Classic and Modern Skins
- Plays Videos (NSV, WMV, and more!)
- Powerful Media Library
- Browse SHOUTcast Radio & TV Stations
- Browse Winamp Music Videos & Songs
- Integrated AOL Video Content (News, Sports, Movies & more)
- AOL Radio Featuring XM
- SHOUTcast Wire (podcast directory)
- Predixis MusicMagic (dynamic playlisting)
- Bundled Visualizations
- Burn CDs (Limited to 2x - 48x in Pro!)
- Rips CDs (Limited to 8x aacPlus, AAC, WMA - Unlimited aacPlus, AAC, WMA and MP3 in Pro!)
- 50 free mp3s from Emusic
- Includes Winner of the Internet
- Surround Music Project!
- Includes an MP3 of ‘Mercy Me’ by Alkaline Trio
- Rip/Encode music into aacPlus, AAC, WMA, or MP3!
- Burn CDs up to 48x!

Changes in Winamp 5.5 :
* New: Bento SingleUI Skin
* New: Auto-Tagger in File Info dialog (powered by Gracenote)
* New: Album Art support, including new window for Winamp Modern skin
* New: Fully translatable Localization support
* New: WLZ (Winamp Language Zip) filetype support
* New: Global ‘playback thread priority’ setting for decoders
* New: Media Monitor and MP3 Blog site scraper (in Bento browser)
* New: Option to set the number of lines to scroll in the Playlist
* New: Option to not show playlist item number in classic songticker
* New: Option to not show the playlist number in the Windows taskbar
* New: Redesigned Installer
* New: Run Setup switch, winamp.exe /REG=S
* New: Unified File Editor, with Artwork tab (for mp3, m4a, wma, ogg, flac)
* New: Version History drop-down selector and Search (in About dialog)
* New: Winamp Toolbar for Internet Explorer (optional)
* New: %family% ATF string for identifying filetypes
* New: $split() ATF function for splitting x/y disc & track strings
* New: [in_mp3] Multi-channel mp3surround support
* New: [gen_ml] Tree Options tab in Media Library Preferences
* New: [ml_autotag] Mass Auto-Tagger in Send-To menu (powered by Gracenote)
* New: [ml_local] 3 pane view options in ‘Add/Edit View’ dialog
* New: [ml_local] Smart View Presets
* New: [ml_local] Album Art support/pane and retrieval service
* New: [ml_local] Toolbar buttons to control view options
* New: [ml_plg] Winamp Playlist Generator (powered by Gracenote MusicID)
* New: [ml_pmp] New fields, configurable filter panes & columns, 3 pane view
* New: [ml_pmp] Album Art view & support for iPod and P4S Devices
* New: [ml_pmp] Separate view for video files
* New: [vis_milk2] Milkdrop2 Visualizer
* Improved: General misc UI/Dialog tweaks & improvements
* Improved: Re-tuned and optimized classic Spectrum Analyzer
* Improved: Surround indicator in Winamp Modern skin for multi-channel files
* Improved: Classic Songticker option for Winamp Modern skin (via Config drawer)
* Improved: [in_cdda] Conductor metadata support
* Improved: [in_cdda] Handling of multiple discs
* Improved: [in_flac/in_vorbis] ALBUM ARTIST & ENSEMBLE read support
* Improved: [in_flac] Advanced Editor mode
* Improved: [in_mod] Added support for more than 256 samples
* Improved: [in_mp3] Faster metadata gathering (also speeds up ReplayGain scan)
* Improved: [in_mp4] Smoother data sent to vis & other minor tweaks
* Improved: [in_wm] Faster WMA/WMV metadata gathering
* Improved: [gen_ff] General freeform skinning engine optimizations
* Improved: [gen_ml] Collapsed/expanded state of treeview items now remembered
* Improved: [gen_ml] Skinned scrollbars in Media Library for newer Modern skins
* Improved: [gen_ml] Reordering of treeview items (via drag+drop)
* Improved: [ml_disc] Better Unicode support & other misc tweaks
* Improved: [ml_history] Unicode support
* Improved: [ml_local] Customize Columns menu for top filter panes
* Improved: [ml_local] Option to show horizontal scrollbar for top panes
* Improved: [ml_local] New ‘Podcasts’ view (appears after downloading a podcast)
* Improved: [ml_local] Added ISPODCAST and PODCASTCHANNEL field names
* Improved: [ml_local] Added BEGINSLIKE comparison operator
* Improved: [ml_local] Dragging of headers to sort column order
* Improved: [ml_local] Redesigned Smart View Editor
* Improved: [ml_local] Star Rating display and selection
* Improved: [ml_pmp] ‘Copy to Local Media’ config separated from CD Ripping settings
* Improved: [ml_pmp] Portables “Sync” can now keep podcasts updated
* Improved: [ml_rg] ReplayGain calculation support for 64, 88.2 & 96 KHz samplerates
* Improved: [ml_wire] Optional automatic downloading of new podcast episodes
* Improved: [ml_wire] Multi-select, ‘Send To’ menu and other general enhancements
* Improved: [ml_wire] Podcast downloads now saved in channel subfolders
* Improved: [ml_wire] Updated podcast directory
* Improved: [pmp_ipod] Now uses the iPod’s podcast menu for podcasts
* Fixed: ‘All supported files’ showing all filetypes in Open Files dialog
* Fixed: Esc key not working in Credits & Winamp tabs of About Box
* Fixed: Long filepaths corrupted when opening Winamp via Explorer context menu
* Fixed: Oversized preference pages with large DPI setting
* Fixed: Recurrence of multiple instances bug (previously fixed in 5.3)
* Fixed: Selecting ‘No’ for ‘Physically Remove’ prompt removes playlist/mldb item
* Fixed: TV button in video window not working
* Fixed: Windows showing if switching from modern to classic skin in minimized state
* Fixed: [ASX Loader] Recursive playlist loading & case-insensitive element matching
* Fixed: [ASX Loader] Handling of entries embedded within a REPEAT tag
* Fixed: [dsp_sps] DEP incompatibility
* Fixed: [gen_ff] “Can’t unload script while in script” error when switching skins
* Fixed: [gen_ff] Remember ML size when switching between Modern & Classic skins
* Fixed: [gen_ff] Transparent docked toolbars for skins using alpha-blending
* Fixed: [gen_ff] 10% opacity not applying on skins that add items to rt-click menu
* Fixed: [gen_jumpex] Crash when loading multiple files via Explorer context menu
* Fixed: [gen_jumpex] Remove Duplicate Entries action broken in pledit
* Fixed: [gen_ml] %playcount% returning Comment on drag+drop from ML to pledit
* Fixed: [gen_ml] Shift+Insert (New Playlist) and F1 (Help) keyboard shortcuts
* Fixed: [in_cdda] CDDB crash when attempting to rip a CD in a 2nd instance of Winamp
* Fixed: [in_flac] General FLAC Editor quirks (Comments field, Enter key, etc)
* Fixed: [in_flac] 24bit files don’t play when ‘Allow 24bit’ setting is disabled
* Fixed: [in_mod] Fadeout value goes below 0.0 sec in in_mod config
* Fixed: [in_mod] Interpolator ‘division by zero’ crash bug
* Fixed: [in_mp3] Crash on some mp3’s with corrupt ID3v2 extended headers (rare)
* Fixed: [in_mp3] Crash on loading corrupt id3v2.3 tags of a later revision
* Fixed: [in_mp3] Negative bitrate in File Info for long mp3’s
* Fixed: [in_mp4] Glitch when modifying metadata on playing track
* Fixed: [in_mp4/libmp4v2] Memory leaks
* Fixed: [in_wave/libsndfile] Crash on invalid .au files
* Fixed: [in_wm] Garbage characters when editing filetypes in config
* Fixed: [in_wm] Potential DRM lockup issue
* Fixed: [ml_disc] 0 byte temp files not deleted after ripping
* Fixed: [ml_disc] Double-click drive icon in Rip & Burn not selecting tree item
* Fixed: [ml_disc] Crash when using in playlist filename generation
* Fixed: [ml_disc] Drag+drop from Audio CD view to Playlist Editor
* Fixed: [ml_local] (no album) items adding to Album count in Artist pane
* Fixed: [ml_local] isempty and =0 queries now return same results
* Fixed: [ml_local] Add dir to ‘Watch Folders’ path truncated to 64 characters
* Fixed: [ml_pmp] Inserting extra period in filename when transcoding to mp4/aac
* Fixed: [ml_pmp] Sending ansi-converted titles instead of Unicode
* Fixed: [ml_pmp] Transfer caption building when Artist metadata is empty
* Fixed: [ml_wire] Subscription Updates setting always resets to ‘Never’
* Fixed: [pmp_ipod] Potential incompatability issues with latest version of iTunes
* Fixed: [pmp_p4s] ‘Error In Insert’ when transferring to some P4S devices
* Fixed: [pmp_usb] Slow Winamp startup when external usb drive connected
* Fixed: [vis_milk] Milkdrop DEP incompatibility
* Misc: Winamp Remote is now an installer option (ml_orb.dll)
* Misc: Moved drawing engine out of gen_ff to tataki.dll
* Misc: Moved freetype font renderer out of gen_ff to freetype.wac
* Misc: Removed deprecated .LNG Language file support
* Misc: Removed db.w5s (replaced by new Gracenote database system)
* Misc: Removed Station Info window and Prefs page
* Misc: Removed unicows.lib/dll as we have officially dropped support for Win9x
* Updated: Gracenote MusicID/CDDB v2.5
* Updated: libpng 1.2.20
* Updated: [enc_aacplus] Coding Technologies aacPlus Encoder v8.1.0
* Updated: [gen_jumpex] JTFE v0.99.2
* Updated: [in_flac] FLAC 1.2.1
* Updated: [in_mp3] FhG Decoder v4.10
* Updated: [in_vorbis] libvorbis 1.2.0