WMA File (.wma): What It Is and How to Open It

The basics

What is a WMA file?

WMA was Microsoft's answer to MP3. It arrived in 1999, when Microsoft claimed CD-quality sound at about half the size of competing formats, and Windows Media Player could rip CDs to it by default for years. Online music stores, portable players and Windows PCs all used it through the 2000s, so music collections and voice recordings from that time are often WMA.

A .wma file is an ASF file, the same Advanced Systems Format container used by WMV video, holding one audio stream encoded with a Windows Media Audio codec. The name covers four different codecs, from low-bit-rate speech to bit-perfect lossless, so two WMA files can have very little in common.

In short

WMA still plays on Windows and in VLC, but no browser supports it, and most music services and devices have moved to MP3, AAC and FLAC. Convert WMA files you want to keep using: lossy ones to MP3 or M4A, lossless ones to FLAC.

Anatomy

What's inside a WMA file

A WMA file is an ASF file with a single audio stream. Like every ASF file it's built from objects, each a 16-byte GUID, an 8-byte size and the contents, with numbers stored little-endian. Here is the full layout of a 2-second stereo WMA we made for this page with FFmpeg, read from the file. It isn't offered for download.

tiny.wma (layout, with key bytes in hex)

tiny.wma: 2 s, WMA Standard, stereo, 44.1 kHz, 64 kbps, 19,904 bytes

offset   object / field                    size     contents
0        Header Object                     654      6 child objects
         30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C
         8E 02 00 00 00 00 00 00 · 06 00 00 00 · 01 02
30         File Properties                 104      6 packets of 3,200 bytes,
                                                    preroll 3,100 ms
134        Header Extension                46       empty here
180        Content Description             78       title "Test tone",
                                                    author "Ada Example"
258        Extended Content Description    182      WM/… name/value tags
440        Stream Properties               114      stream 1:
             40 9E 69 F8 4D 5B CF 11 …              type: audio
             50 CD C3 BF 8F 61 CF 11 …              error correction: audio spread
             61 01                                  format tag 0x0161: WMA Standard
             02 00 · 44 AC 00 00                    2 channels, 44,100 Hz
             40 1F 00 00                            8,000 bytes/s = 64 kbps
             73 01 · 10 00                          371-byte blocks, 16-bit
             0A 00 · 00 00 00 00 01 00 …            10 bytes of codec settings
554        Codec List                      100      "Windows Media Audio V8"
654      Data Object                       19,250   6 packets
         36 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C
704        packet 1                        3,200
             82 00 00 · 09 5D · 53                  flags; 83 bytes of padding
             00 00 00 00 · 45 01                    send at 0 ms, lasts 325 ms
             88                                     8 payloads follow
             01 01 00 00 00 00 08                   stream 1, block 1, offset 0
             73 01 00 00 1C 0C 00 00                371 bytes, play at 3,100 ms
             73 01 F1 BF D0 …                       the compressed audio
…        end of file at 19,904 bytes: no index

130 26 B2 75 8E 66 CF 11 …
Same start as a WMV
The ASF Header Object GUID. WMA, WMV and ASF files all begin with it, so the first bytes can't tell audio from video; a tool has to read on to the stream types.
28E 02 00 00 … · 06 00 00 00 · 01 02
Header size and contents
The header is 654 bytes (0x28E) and holds 6 objects. The 01 02 that ends this part is fixed by the specification.
3Content Description, Extended Content Description
Tags
Title and author sit in fixed UTF-16 fields; album, genre, track number and cover art go in the extended object as named attributes such as WM/AlbumTitle, WM/Genre, WM/TrackNumber and WM/Picture.
440 9E 69 F8 …
An audio stream
The stream type GUID F8699E40-5B4D-11CF-A8FD-00805F5C442B marks audio. A WMA file normally has exactly one such stream and no video.
550 CD C3 BF …
Audio spread
An error-correction method for streaming: blocks of audio are scattered over several packets, so one lost packet costs a few short gaps instead of a long dropout.
661 01 · 02 00 · 44 AC 00 00
The format tag
A Windows WAVEFORMATEX structure. Its first two bytes say which WMA this is: 0x0161 Standard, 0x0162 Pro, 0x0163 Lossless. Then channels and sample rate.
740 1F 00 00 · 73 01
Bit rate and block size
8,000 bytes a second (64 kbps) in blocks of 371 bytes. Each block is a media object that packets carry as payloads.
882 00 00 · 09 5D · 53
A data packet
Flags, then 83 bytes of padding to fill the packet to its fixed 3,200 bytes, a send time and a duration. 88 says 8 payloads follow.
91C 0C 00 00
Timestamps with preroll
The first block plays at 3,100 ms, not 0: the preroll from the File Properties object is added to every timestamp. Players subtract it, which is why the audio still starts at zero.

Variants

WMA Standard, Pro, Lossless and Voice

Codec	Format tag	What it's for
WMA Standard	`0x0161`	Ordinary music and audio at typical bit rates, mostly stereo. By far the most common: CD rips, music stores, podcasts.
WMA Pro	`0x0162`	Higher quality and surround: up to 24-bit, 96 kHz, in stereo, 5.1 or 7.1 channels, with download bit rates of about 128 to 768 kbps.
WMA Lossless	`0x0163`	Exact copies of the original, usually compressed to between a half and a third of the uncompressed size. Used for archiving CDs.
WMA Voice	Its own tag	Speech at very high compression, for spoken-word streams and recordings at low bit rates.

Microsoft's codec version numbers (WMA 7, 8, 9, 9.1) refer to encoder releases. WMA 9 Standard files stay readable by older WMA decoders. Some tools use a different numbering: VLC lists WMA 1/2 and WMA 3, and FFmpeg calls the codecs wmav1, wmav2 and wmapro. Those names come from the internal format tags, where Microsoft's constant for Standard is WAVE_FORMAT_WMAUDIO2 and for Pro WAVE_FORMAT_WMAUDIO3. So "WMA 3" means WMA Pro, not an old version.

Which one do I have?

Run ffprobe song.wma: it reports wmav2 (Standard), wmapro, wmalossless or wmavoice. In VLC, Tools → Codec Information shows the same, and on Windows the file's Properties → Details tab shows the bit rate.

Under the hood

How WMA uses the ASF container

Compared with an MP3, which is little more than a run of audio frames with tags at the ends, a WMA file is heavily structured:

A header first, with the stream description, the tags, the duration and the bit rate. A player knows the duration and bit rate before it reads any audio, where an MP3 player sometimes has to guess.
Fixed-size packets, each holding pieces of one or more audio blocks with a timestamp. The design comes from streaming over unreliable connections; it costs a little space for padding.
An optional index at the end for seeking. Audio-only files often leave it out: with packets of equal size, a player can estimate where any moment is.
Room for DRM. Encryption objects in the header mark a protected file (see below).

Tags in WMA work differently from MP3's ID3: there's no tag block bolted onto the file, just attributes in the header. Most tag editors handle both, but a converter that copies the audio without its header metadata will lose the tags.

Protection

Protected WMA files and the music-store era

Many music stores and subscription services of the 2000s sold WMA files protected with Windows Media DRM. The audio is encrypted; the key comes in a separate licence from the seller, which the player stores on the computer that obtained it. The licence also holds the rights: how many computers or devices, whether you may burn a CD, sometimes an expiry date for subscription music. Windows Media Player could also copy-protect the files it ripped from your own CDs, if that option was switched on.

Those files only play where a valid licence is present. Move them to a new PC, reinstall Windows or let a subscription lapse, and they stop. When a store closed, it could no longer issue licences. In September 2024 Microsoft announced it was deprecating its legacy DRM services; when they're fully retired, protected content will no longer play in Windows Media Player on Windows 7, in Silverlight or on Windows 8, and protected rips of personal CDs on Windows 7 stop working too. Microsoft recommends PlayReady for new protected content.

What you can do

Play protected files on the computer where they're licensed while you still can, and for music you want to keep, buy or download it again in an unprotected format. VLC and other players don't play protected WMA. Avoid tools that promise to remove the protection: many bundle malware.

To spot a protected file, run ffprobe file.wma: FFmpeg prints DRM protected stream detected, decoding will likely fail!. Unprotected WMA files, including most CD rips, play anywhere VLC does.

Related formats

WMA vs MP3, AAC and FLAC

	WMA	MP3	AAC (M4A)	FLAC
Owner	Microsoft	ISO/IEC (MPEG)	ISO/IEC (MPEG)	IETF standard (RFC 9639), Xiph.Org
Lossless option	WMA Lossless	No	No (ALAC is Apple's lossless format in M4A)	Always lossless
Plays in browsers	No	Yes	Yes	Yes
Apple devices	Only with VLC or similar	Yes	Yes	Yes
Good for today	Reading old files	Compatibility everywhere	Better quality per bit, the web	Archiving and lossless listening

At the bit rates people actually used, WMA Standard sounded about as good as MP3 and was soon matched by AAC. What decided the format's fate wasn't sound quality but support: Apple's iPod didn't support WMA, browsers never added it, and music stores moved to unprotected MP3 and AAC.

How to

How to play a WMA file

Windows 10 and 11: double-click it. Windows includes the WMA decoders, so the Media Player app plays it. Windows Media Player Legacy is an optional feature in some editions of Windows 11 and is the one that handles old protected files.
macOS: VLC or IINA. Music and QuickTime Player can't open WMA.
Linux: VLC, mpv or any player built on FFmpeg or GStreamer with the FFmpeg plug-in.
iPhone and Android: VLC plays WMA on both. Some Android music apps handle WMA Standard; iPhone apps other than VLC rarely do.
Car stereos and portable players: many from the 2000s and 2010s play WMA Standard but not Pro, Lossless or protected files. Check the manual; if in doubt, convert to MP3.

How to

How to convert WMA to MP3, M4A or FLAC

Which target to pick depends on what's inside. Converting lossy WMA to another lossy format loses a little more quality, so use a generous bit rate. Converting WMA Lossless to FLAC loses nothing.

terminal

# check which WMA codec it is
ffprobe song.wma

# lossy WMA to MP3 (VBR, LAME's -V 2 setting)
ffmpeg -i song.wma -c:a libmp3lame -q:a 2 song.mp3

# lossy WMA to AAC in M4A
ffmpeg -i song.wma -c:a aac -b:a 192k song.m4a

# WMA Lossless to FLAC, bit for bit
ffmpeg -i song.wma -c:a flac song.flac

Without the command line: VLC's Media → Convert/Save converts WMA to MP3 and other formats, and so do most desktop audio converters. Windows Media Player Legacy rips CDs but can't convert files.
Tags: FFmpeg copies title, artist and album across; check cover art and track numbers in the result.
Many files: a shell loop or foobar2000's batch converter handles a whole library in one go.

Troubleshooting

Why won't my WMA play? Common problems and fixes

Symptom	Usual cause	Fix
Asks for a licence, or says you don't have rights	Windows Media DRM, and no valid licence on this computer.	Play it where it was licensed, or get the music again in an unprotected format.
Won't open on a Mac or iPhone	Apple's apps don't support WMA.	Use VLC or IINA, or convert to M4A or MP3.
Plays on the PC but not in the car	The file is WMA Pro or Lossless, or protected; many devices only handle Standard.	Convert to MP3.
Downloads instead of playing in the browser	No browser decodes WMA.	Convert to MP3 or M4A for the web.
A rip from years ago won't play on a new PC	It was ripped with copy protection switched on.	Rip the CD again without protection.

Sample files

There are no sample WMA files on this page. To make one for testing, run ffmpeg -f lavfi -i sine=frequency=440 -t 5 -c:a wmav2 -b:a 128k test.wma, which writes a 5-second WMA Standard file; FFmpeg can read WMA Pro, Lossless and Voice but can't write them.

Put it online

Have a WMA file? Give it a link.

Drop a WMA on 99helpers and it gets its own address to send instead of an attachment. Browsers can't play WMA, so the file downloads when the link is opened; for audio that plays in the browser, convert it to MP3 or M4A first.

Put a WMA online

Questions

WMA files, frequently asked

What is a WMA file?

A Windows Media Audio file: sound compressed with one of Microsoft's WMA codecs in the ASF container. It was common in the 2000s for CD rips, music stores and portable players.

How do I play a WMA file on a Mac or iPhone?

Use VLC, which is free on macOS and iOS, or IINA on a Mac. Apple's Music app and QuickTime Player don't support WMA.

How do I convert WMA to MP3?

Run ffmpeg -i song.wma -c:a libmp3lame -q:a 2 song.mp3, or use VLC's Media → Convert/Save option. Protected WMA files can't be converted without a licence.

Is WMA better than MP3?

At the same bit rate, WMA Standard is roughly comparable to MP3. MP3 plays on far more devices and in every browser, which matters more today.

Is WMA lossless?

Only WMA Lossless is. WMA Standard, Pro and Voice are lossy. ffprobe reports wmalossless for the lossless kind.

Why do my old WMA songs say I need a licence?

They're protected with Windows Media DRM, usually because they came from a music store or were ripped with copy protection on. The licence isn't on this computer, and only the store that sold them can issue a new one.

Can browsers play WMA?

No. No current browser supports WMA, so a WMA link downloads the file. Convert to MP3 or M4A to play audio on a web page.

What's the difference between WMA and WMV?

Both are ASF files. WMA holds only audio; WMV holds video, usually with WMA audio alongside.

Related formats

Other file types explained

MP3 file M4A file AAC file FLAC file WAV file WMV file All file types

Keep going

Host a WMA file

Put a WMA online at its own address for others to download.

Share a WMA file

Send audio as a link instead of an attachment.

Hosting guides

How to put different kinds of files online.

Sources

Last reviewed 27 October 2026.