Nullsoft Winamp is a fast, flexible, high-fidelity media player for Windows. Winamp supports playback of many audio (MP3, OGG, AAC, WAV, MOD, XM, S3M, IT, MIDI, etc) and video types (AVI, ASF, MPEG, NSV), custom appearances called skins (supporting both classic Winamp 1.x/2.x skins and Winamp 3 freeform skins), audio visualization and audio effect plug-ins (including two industry dominating visualization plug-ins), an advanced media library, Internet radio and TV support, CD ripping, and CD burning.

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